STRESS CORROSION CRACKING STAINLESS STEELS A ...

STRESS CORROSION CRACKING

STAINLESS STEELS

A Bibliography

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'. '1

STRESS CORROSION CRACKINGOF

STAINLESS STEELS

A BibUography (1962-1971)

: . Stress corrosion clacking which can be rightly termed as the

cancer of metals, presents ma.jor problems with stainless steels in

applications where they are otherwise ideally suited. Hie significance

of this fact in nuclear industry, which uses these Stainless steels

in large quantities, is of no small importance* A thorough knowledge

of the mechanism of this detrimental process and the mitigation

procedures to be adopted to avert the occurrence of major mechanical

failures would be of great interest to the Corrosion Engineer. An

-exhaustive bibliography on the subject is presented here, embracing

all .aspects of the problem. Specific reference has been made on the

cracking of austenitic'stainless steels. Hie compilation coders the

period January 1962 - June 1971• The sources consulted are i-

(1) Nuclear Science Abstracts

(2) Chemical Abstracts" " ' • ' ,

(3) líe tal a Abstracts

(4) INIS Atomindex." . .

387 references have been cited and arranged alphabetically

by first author. E3ch entry is provided with an abstract. Author

and key word indexes are provided. "-'••'

,:' -if -. --• ',,-

• : • • *

)•• .~?V"

Bibliography '

Addendum

AuthortIndex';.

Keyword Index ••".".•

IS.

Page .

1

134

148

152

• ^ Tj - • '.<<« •

?•> \&-:i- A - ^c-

•BIBLIOGBAPHY

S. J

-. .1,422,764: ' 24 (Patent) . *'.-;.. ; "". . * , : . .

^ ; ^ p ^ 0.15,; Or."'15-22, Hi 3-8, Si 1»4,Mn 0-2¿5» Mo 2-4-, and óne, ór abré, elements such as Nb,/Ta,. and ; Ti1,5/wb¿?jtt, maxw;j the r e s t béin^FIy.possess high resis tance to ... •'.",.corrosion under" s t ress and to corrosion by p i t t i ng and are easi lyfpiked.and welded,.';;The-proportion--of elements in the alloy, i s dietd*

:by-the. formulas^Si ->¿-•"• 0.15Cr-i .# and'23*0;-'-2fc' Cr +3 Si +Mo+ÍOTi+4KtM.'2Ta-iri-r;oV5ll&i -20Ó-10IÍ ^i8.p, .where>the ;ph,eEi. symbols representC[uanti:ties in $1 in" order, that tile s tee l contains 40-95$ by vblf e r r i t e , the - res t being Pey and con-cg*'CTO-,044, IT 0.Q2Í, INb 0%67;^ :^ 0^Q5;; Si^ 1 ^ 9 i ^ i .83^ :Gr] Í8 .7 , .Ki 6*8, and^Mp.

resjb -being.;Pefi^ and dónrg.,7C^,^^r'Phase/and 3( 5 ^r-phase, . was v

^ 97 " " f Éj g ; f i ^ g ^ ^ ^ P ^

annealed for 3^2 h r . at-975° • and""-sfas^temperéd in É-fl.»^ The al loy liad^plnsv While i n catact fbr '7 daysvfith boi l ing 10^ oxalic api'dy.'.thealloy was not: affected. The alloy was al^o not affected by p i t t i ngcorrosion; inVá l ^ KCl'sólñ. liaving a ¿K of 3 or i n a 7.5^ KC1 spl^»:having a pH of ?,

y ^ y pKCl'sólñ. liaving a ¿K of 3 or in a 7.5^ KC1

'' ' l ' ' ' t 'Alekseenko, .'et.al

EPPEGT OP TÍMPERIHG TIMPÍEÁIURE, pCHAKICAL THEATI.1EÍIT, CIJA APPLIED .' S5HESSES;ON 37HE SÉNSIVITY OP CHHOMIüM-líICpÉ. STEEL, l?3il2N2VliPA TO.

i GOEBOSION OHACKIHG.; ( in Russian.) - y ; : : / \ i^ ';'']'":.•'.:*'";-/, " : 4

í ; - ; F i z v ^ i a i í ^ ••• "••:'' .•••"•• ';-•- : ; j : . . '

The .effect of tempering teirtp. and mechanical txeatraent on the sensivity%of CrrNi steel, 1EU2K27MPA to, corrosion *ab. studi ed.' The steel in thevas-'.q.u.enclieó; s t a t e was very l iable: ta.corrpsion cracking, bui on

; ¡raiding ftttíe tempering temp» 'this" t.enSiency dimináliéd, except in a f

(restriqiied tepp»\ range close r to 475CGJ. •' Steel par ís : to be used -in',;,.Contact-, witK seá-iraté^ required:higH : tempering in order to prevent :'

c r a c k i n g . ~"'i'- % i ";'•••.-''"-.''"%.' "~. ' ' ' ' ^ - ' : , v . ' : - ° ' r '.-,•"'; * "-•'"•••;-•"''• ":-" '-!. .-''' ••*'"5,-

-1. --

I. _* \

I-, - ^ -1

«>.'t¿S . ^--^

• I

$ < • '•>:• ' • '

3 .

•«»• . • • • • * " - : - .

tó

.' - . / ' ^ i - ' " ' - •

^ M . OP:

a- a •--.,•- "if:-::- -it

Tl-shispé .Mfd ilíé t rÍ3 p p e c i ^ i í - were then

and-:

csieaaed and:ooye|reá

-.OR-'-r- ':

fiiín oí;

• ¿ i i W ' 2 ^ ; ^ - - ^ l á l l o g r a p l ü q :abt3¿°f £ :

I,. .« •> •

¥f,;,^

STBJESS (jqÉííÓSXOH, CMCKIBG OP 18 r8^ Í SULFATE YE?SEL$;.. V y

I í '

but fcTCtm severely órackéd areas oícs^télülee3 s tee l ;¿Téfl=seIs°usect i ñ the áaímf» of (lK5¿)S>b¿ by.«tHe ^g^pstün ;

/ ¡ :''••'.j-p'róceSjs»'. ^ Filings^froiálthésé sáinplea were exantd, fy x2r^y, diffiactibtíw- •;í ; totrosion prMu^ :? * " " ^ >i

thés sfeel ±e°

• • : " g '• =' , . - '

J.effecti'

5.» Airad . jo ," J S .

' ' •". /INTERGRANDLAR STRESS CORRO SIOK. CRACKING' OP AUSTENITIC STAINLESS STEELSI B " OXYGENATED, HIGH-TEl/IPEEATURE WITER.

- ' " " ' » » •

Corrosion 24í10, 319-25; 1968* ' • .

•A bellows arrangement, for. controlling Jiigii teiap. f high pressure,stress corrosion tests of thick specimens.was used to study the

Vintergranular,stress corrosion cracking of type 304 stainless steeland Incoloy 80Ó in oxygenated (/-ylQOppm») 288° water, • Completeintergranular fracture of- sensitized type 304 stainless steels occurs

. . after 10*4 hrs» exposure at stress levels of 14,000-17 psi#• ,.. . Cracking of Incoloy 800 requires longer exposures at high stress»

.. Crevices are not necessary to initiate cracking of sensitized.. alljeys.. The effects of .dissolved corrosion products and soln» pH.must 'be detd» "before the intergranular" stress "corrosion cracking of

v áustenitic stainless steels in oxygenated high-temp* water can"be understood»" • ..

6» ¿ s a w a , M -• ' •. • . • . i •'

. . STRESS CORROSION CRACKING OP 18:8 AUSTENITIC STAINLESS STEEL INSULPHURIC ACID CONTAINING ..SODITJM CHLORIDE, ( in Japanese)

J, Japan Ins t . Metals, 34:8, 871-77; Aug» 1970;' •

18:8 aus teni t ic s ta in less steel, i n the form of U-shape specimens was: .. exposed to'EUSO,, contg. NaCl and 'Na^SO. and the effects of H. ions,

sulpliate ions , .and chloride ions oñ the corrosion a t temp» between/ . ,25 and 65°C was observed. • In the s.trong acid solut ions, the corrosion

re te was decreased, by the adsorption of chloride ions on the metal•surface. Stress corrosion cracking was produced, when dissolut ion, .

' accelerated by the in terac t ion between the stressed metal andchloride ions , was localized by the adsorption .of chloride ions andsulpliate; ions . 16 references. ,

7 » . A s h b a u g h j W ;G \ : .' . \ ,\ •-[, •' ' . ,

. ' . ; • STRESS CORHftSION CRACKING OP PROCESS E0IBEEM.Z ,r :- • "

Chem". Eng. Prdgr) 66:10, :44-7;. 1970, J •

Principles and ;páramet<jrsof;> stress,cracking fai lures in materials 'are reviewed» Exampleá^jPfehloricLe and caustic s t ress cracking In

.. Inconel, s ta in less s^teel, and carbon steel are discussed» -.

:" . - . , - * 3

• , ' / - • -

8 . B a b a k o v , A A e t a l '.--'_.-_"- r •_•.••/"-, • ' = .,_"''

. CORROSIÓN CRACKING.OF STAINLESS STEELS IN 42$ MAGNESIUM CHLORIDE*

. . Metal Sci. Heat Treat*j 11:12, 9£Í5-88|...Nov.-Dec. 1969. •

9,« Babakov, A A et al •'. • ' r .

STRESS CORROSION CRACKING. OF. STAIHLESS STEELS IN BOILING42$ ' \-MAG^ESITJM,CHLORIDE., (in Russian) ' .. - ;

Metalloved./Term. Obra"b. Metal. 12, 57-9; 1.969. • . .'••• ; ."

The resistance to corrosion cracking of various stainless steels in •; "boiling 42$ MgClg (b. Í54°) was, studied by plots of strength vs,. . time to cracking. Cr^Mh-Ni steels were not. as stable as Cr-Ni •

steels. In aiistenite-ferrite steels" the stability depended on the^-ferrite mau be as seed, with the fact that 2-pliase steels are

' • strcnger than puré austenitic steels.. Alloying with r^j B$> Mo" lowered-the stability. Tiae ratio of long term strength to th'e yield point

. may be used tó evaluate the stability of steels. Steels ,OKhl?T andKh25T of the ferrite class did not crack. \ "

10 , Babakov, A A. et al .; .' :' ,-

CORROSION'CRACKING OF STAINLESS STEELS IN B0ILI1Í& . .; CHLOBIDE. (In Russian) . . . • .•• •-.- \: ';.•/- ..

MáGFESIÜM

Metal lav edenie i Term,. Obrabot. Ifetallov, -/12, ,57-*59; 196.9.,'-;. ' . " . ' .

Tiie corrosion cracking "in boiling. 4?? ligOlg of a number of types of¡Cr-Ti and Cr-Ni stainless steeís was studied. oTwo= types of Cr-tisteel of the-ferritic class, in particular, were not susceptible tocorrosión cracking. For two-phase steels the resistance to corrosioncracking, increased considerably if 10-30$ a p-fe^?rite was. present -.ill t"".e steel» The presence- of Mo 2 $ reduced tí§5 resistance ofstainless steels to corrosion cracking, both in ^le/case of .aus.tenitic and.o ferritic-aijstenitic materials.-. 7 references. *•-

4 «,

11* Backensto, E B j Yurick, A If

STRESS-CORROSION CRACKING STUDIES OF AUSTENITIC STAINLESS STEELS IN!..;•> AQUEOUS AMMONIUM CHLORIDE SOLUTIONS.' .

Corrosion 18, 169t-175j 1962.

±2i Badartj A etal . .

STUDY OP STRESS CORROSION AND OP GENERAL CORROSION OP STAINLESS STEELSIN DILUTE SOLUTIONS OP CHLORIDES AT 350°C TO 360°C AND IN STEAM AT5P0°C« EVOLUTION OP THE MECHANICAL PROPERTIES AND OP THE STRUCTUREAT THESE TEMPERATURES POSSIBILITY OP MAKING USE OP PROTECTION BY

. SURFACE CHROMIZATIOH. (Plnal^Report)

EURAEC-194? (Pt,2) 71p. Oct. 1967. . •

Tests were performed on eight grades of stainless steel four with anaustenitic structure arid four with austeno-ferritic structure» Theinfluencie of molybdenum and/or silicon additions were, studied.Silicon steels display a certain tendency to embrittlement, toward300:to 400°C for austeno-ferritie steels and 500 to 6OOeC foraustenitic steels» The effect of silicon in stronger than that ofmolybdenum additions which produces also a certain embrittlement inthe case of austeno-ferritic steels, toward 350°0 to 400°C. Silicon-improves the mechanical characteristics and' the resistance to creepfor short himes. Molybdenum improves the resistances to creep. Thediminishing resistance to creep of silicaon steels, over longdurations', is probably due to structural transformations making ituseful to study these transformations by the technique used inphysica?. metallurgy..

13. Bade, -Jj Dodd,-R A . ..

- , CARBON-AND NITROGEN'EFFECTS IN THE STRESS CORROSION CRACKING'OFAUSTINITIC STAINLESS STEELS/ • ;

Proci Conf.,.Fundam. Aspects Space Corros. Cracking 342-51} 1967.

The effects of-N and C on the stress cracking of austenitic stainlesssteels in chloride environmenirs vary with the compn. of the steel. .Steele wliich intrinsically are either highly -crack-susceptible orhighly crack-resistant are little affected by higher-interstitialcontents. Steels of intrinsically moderate crack resistance,aremade'more crack-prone by N addns., and rather less crack-proiie bjiC addns. = • ''

" 5 - - , ' ' • • • - ' ' • ;

• - • - . ; . . .

. . . . Contd....

Transmission, electron metallography indicates that these interstitialsmay exert significant influences on the defect structure, dependingon the. initial stacking fault energy, but the overall correlationbetween defect atructur.e and stress cracking propensity is poor.Since C and N seem to exert their great-est effect in the regionof the Fe-Cr-Ni phase diagram where• aust-enite is unstable, these .elements may pláy some important role; in the structural stability."of alloy atoms at the crack tip. Changes from austenitic to ferricstructure are accompanied by a chem. change. This local chenu .change may provide a local dissoln. at.the crack* tip. '•,*,•

14. Báiley, S O

STRESS CORROSION CELL.

U.S. 3,449,232 5p. June 1969. (Patent).

The cell is designed to indicate'.effects of differential aerationon stress corrosion performance of metals. The mt-tal specimen isclamped over, an opening, from which a. pas-sage leads toa reservoirof electrolyte within the cell. A reference electrode, usuallyconsisting of a sep. specimen of the same metal, is clamped to an -inner support member at a level above that of the electrolyte.A strip of medical gauze or. capillary strip is placed over thereference electrode and dips into' the electrolyte which rises-."by

- capillary action to maintain a film-over the surface of the metalreference electrode. As the film is-thin and is exposed to the airwithin the. cells,, it remains satd. with" air, whereas the: electrolytein contact with the metal specimen under observation soon becomesdepleted in dissolved gases.. Provision is made for circulating air inthe chamber above the.electrolyte. The 2 electrodes are .connected to

"a suitable'circuit to measure potential- and current flowing. Theends of the test.specimen are accessible for"applying suitable -stress during the test. In this way corrosion generated by . .differential aeration can be .measured, and-the ..effects of stress on-their "magnitudes detd. . . :'•-:•. "

15, Baker^ E R ét al • .._..-"-'.-_-. ' ' '.

FILM AND pH EFFECTS IN THE STRESS CORROSION CRACKING. OF TIPE 304STAINLESS STEEL. - . ,. _-. ';:. '• -.. ' • ,: " "

Corrosion, 26:10/420-26; Oct. 1970. ,• ".< .

Rapid stress corrosion cracking of 304 stainless steel in MgClg- FeCl3solutions at 125°C occurred only when:the pH of the corrodent liquidwithin the crack lay "between7 1.2 and. 2.5 A film of more acidiccorrodent solution is raised to pHrl.2 by reaction with -the- metal withina few seconds after isolation in a pit, crack or crevice.

- 6 - Contd..._.

MgClp solutions of pH higher than 2 became moré acidic when thecontact wi-fch stainless steel as a result o.f corrosion processes.•The pH of small amounts of'such, solution isolated in pits or creviceseventually fell to near 1.5j where stress corrosion cracking couldoccur. This pH range is considered to he critical for stress^corrosion cracking of 304 stainless steel because it is the rangein which a corrosion resistant protective film is formed in thepresence of the corredent solution. This film is essential to crackpropagation» If there is added to a corrodent, solution in th^spH range an,organic cómplexing agent such as glycerine or glycol, -which prevents formation'of the protective oxide film, the generalcorrosion processrcontinues unchecked, but no stress corrosioncracking occurs. The data support a model in which stress corrosioncracking is driven by a highly localized galvanic cell within the .crack.- The cell'operates in such a way that there is no large changein p'H. of the Solution in the. crack» These results emphasize theimportance of the corrosion resistant film in the chemical aspect of thethe stress corrosion mechanism» 22- references. . . ,

16. .Baker, H R et-al

' FILM AND pH EF.FECTS tS THE STRESS CORROSION CRACKING (SCC) OP TYPE. . 304 STAINLESS STEEL. . • .

Coxrosion-26:10, 420-6; 1970. •

An exptl. study o"f the rapid SCO of TJ-bend specimens of 304 stainlesssteel in MgClg sblns. at" 125° showed that the pH-within an activestress fiorrogjnri rtraok was 1.2-2.0 .(.as measuxed-with indicator paper.in cooléd sóln.) Cracks were initiated in. the largest nos. when the pKof the main corrodent soln. ia 1.2-2.0. Under the conditions^studied the formation of a corrosion resistant film on the crack wallswas an invariable and probably" a. necessary feature of. the SCC process.

17. - Barnhartt, S^ • _.'..' '

SYMPOSIUM-ON CORROSION THEORY. GENERAL COHCEPTS OF STRESS-CORROSION.C R A C K I N G - . , . •-. •' V .'."--. : .•'-" • " * ' - . - . ' •

- /Corrosion 18, 322t-331; 1962.' ,,.'•/ I ';.'-' ' \ •

- •'=• The periodic ^electrochemical mechanism of cracking appears to be'' , generally applicable to and haá been confirmed with stainless steels

and copper- alloys. ° r „ ' s '•-"'".- ',,

".. •» ' 7 • «•

18. Barnwell, 7 1 . e . t a l . . . , . ' •'• •"-•} , - - ... ;•

: EFFECT -OF GBAIN SIZE ON STRESS CORROSION OF TYPE 302 ATJSTENITIC..STAINLESS. STEEL. . . : 'i • ' .: , " . " '• • " •'•'- - : . '

. Corrosion 22:9, 261-6.4; 1966. -

18:8 Type, s t a in less s teel 'gave decreased res is tance to cracking' forincreased grain s izes in boiling ^^MgClg: soln. This effect VB.3associated ten ta t ive ly with a décreased^inciibatlon period and i s

: , discussed in ' terms of a dislocation model for.crack i n i t i a t i o n with;gra in-s ize dependence». 15 references. ' • • ' " ,

19. Báruárt t , S et a l • - \ , ' . , . . • :

-. " •' STRESS CORROSIOF CRACKIMJ iáECHAKTSM IN PÜMFIÉD 16?o. Qv-2Qffo MSTAINLESS STEELS. ' . * " - • . ' • ' ,

Corrosion Sci.. 3 : 1 , 9-16; 1963. • /

Further data are. presented on the electrochem. behavior in .bo i l ingMgClo soln. an on the nature of cracking propagation and.s l ip in4 16$> Cr-20$ Ni s ta in less s t e e l s , with andwithout single-ele"mentaddns'. of l&i, Mo, and Ti a t the 1.5,1.5, ..and 0.5?é l e v e l s , ifesp.-'-' .Corrosión poténtis . curves were l i t t l e affected by applied s t r e s sup to 4 x 10^, l b . / s z . in-for the parent alloy, and that contg. Mn;

.'._ .. Ti and Mo imparted-süspect ibi l i ty, esp. the l a t t e r . A po ten t ios ta t i ct e s t a t -340 mv, produced no cracking in anjr of the 3 modified a l loys ;

. p i t t i n g at tack resul ted in. ultimate me t a l fracture* Crack propagation-. ;Ln .the Ti.and Mo alloys was similar;, d is locat ions appeared coned»

¿along pa ra l l e l s l i p planes in each a l loy , i n agr§ement with theory,and a low stacking-fault energy was indicated. Tlie>2 immune alloys

cwere- expected to sKow easy cross s l ip; this was confirmed, and the data Igenerally with, the restriéted-j3lip model of stress corrosion / ; . 1cracking. The general corrosion of stress cracking and stacking-fault energies of 25ergs/enu^ were deduced.for the basic alloyand i t s modification with Mh./ while values of 20 and 15 ergs/cm.^ .were given for the Ti-and Mo-Contg. corapns. 20 references* . .

20. Bates', E Fj Loginow, AW . . . " <v_," - • . < •] '/.., '

PRINCIPLES-OF; STRESS CORROSIÓN CRACKING AS RELATED'TO : STEELS. •

. Corrosion 2 9 : 6 , 1 8 9 t - l 9 7 t ; 1964¿ •» '\ \¿\'[••"-\ ~- '

, Tlie medhanism of stress corrosion, cracking1 in discussed with specialre-ferencesto Fe alloys! as well as the effects of^steel compn., stresslevel, cpld welding, ;and corrosion environment on susceptibility.Preventive measures, are reviewed. " 31 °references. \

.J

,21.; ¿ates, _ J F V •.,;, .. \ , .. .".'- " ' , . s .

THERMOMECHANICAL EFFECTS ON STRESS J CORROS ION CRACKING OP AUSTENITICSTAINLESS-STEELS, ". ../..' * ' '. ' - .' ' • . .

Proc. Conf.. Nat. Ass. Corros'. Eng. 320-6j 1970.=

Thermomech.- treatment bf.austenitic: stainless steels enhance mech. .properties and resistance to stress corrosion cracking» .The effects ofthis treatment are small but "real for stable austenite USS 18-18-^2

. and more.pronounced for metastable austenitic stainless steel.

22. Bate*, J F ' ' " . • , ; '

' THERMOMECHANICAL.EFFECTS OH. STRBSS CORROSIÓN CRACKING OF,AUSTENITICS T A I N L E S S S T E E L S * • _- '- ...•' '."'';•'•- ' .. ••

'- Mater. Proti Performance, 9:10j 27-32? Octi 1970Í

Variatidhs in cold reduction, refrigeration and annealing times and -téóp« can markedly affect resistance to stress corrosion cracking.In these studies, cold raductipn prior to the final annal wasbeneficial and low-temp, annealing.was" detrimental to a stable. austenite. Thermomechanical treatment of a metastable alloy affectedits resistance to stress corrosion* 21 references.

23. Bates, "f"F'"'"~~?'~ -:'~'"• =

EFFECT STRESS ON COREOS ION. , = -

> Ind. Íég«.chem*_ 58:2,918-29i 1966.; *. .- •. ' • i

— Á review of stress corrosion, and corrosion-fatigue phenomena in the1 press industries. 57 references¿

24.- Baumel, A, . : ,. ' . . T

"L VTRáSSCRYSTALLINE^STRESS^OSROSÍON CRACKING OF AUSTENITIC MANGANESE 'J 4 STEELS IN ¿MEDIA CQÑTA1NÍNG .CHLORIDE IONS. (lvt German) /

¡ =, Tests were carr ied out i n U-shapéd t e s t pieces of 0.5$-20$¿ ¿

¿í ;^ Mñf-Óí"2-2a.79é S r í l t e e l s xa sea water atsrpom temp* and b»p. , underI ' ; Ipacte of^30-45 fcg/inm2. The: electrochemical .behaviour of s t ee l s

; contgv *^-0,5^ C r a t room temp, i s the 3ámer as that--of f e r r i t i c' Shipbuilding s t e e l s . ^Addition of °Ni,Co, and Cu have - l i t t l e effect on

,the pqtential^behavLour. In boi l iag sea-water, tran&cryst%.lline: . * corrosiog, occurs, which i s accelerated by tension "and anodic6

t . polar izat ion,"and slowed by cathodic po la r iza t ion . . / \; r° '" " -- - C - ° = — 9 ~-~ ° - ' ° ' '"• ~' ' . = .-. ' ' " r' - ' '

- . " ° c = :„ •-.; = C o n t d * . . « '

I1 ,'-s

, -. I.

Co'and Ni, additions reduce specimen life. Át Cr contents ,1.7-2-..7$,intercrystalline corrosion supercedestranscrystalline crackingsusceptibility. There are parallels between the behaviour of ;.~-- -Cr-free austenitic." Mn steels in sea water, and 'that of -' austeniticstainless steels in CaGlg solutions.. 10 references^ \ ' - ' ".

25. Seek, F E et al . - ' . . ' - ' .

Á STUDY OF THÍ3 MECHANISM OF STRESS CORROSION CRACKXMJ IS THE IROST*. •• NICKEL. CHROMIUM ALLOY -SYSTEM. % ( Q u a r t e r l y R e p o r t , March. 1 7 - J u n e 16,

' " 1954) . . " • ; • -•• ' t j .

COO-1319-15 (1964) , " .• - * ' " ,

26. Beck, P E e t a l . ' • - "

A STUDY* OP. SHE MECHAUISM OF'STRESS CORROSION CRACKIiiG INTHElROH.HICKEL-GHROMUfM ALLOY SYSTEM. ( Q u a r t e r l y Repor t , S e c . 17 , 1963 -

* March 16 , 1964) . . . " ' • ' . .

' ' • •

000-1319-12- (Mar. .31,, 1964)

2 7 . B e i e r , E ' , . . .

CAUSES Aró CURES OF STRESS* CORROSION.• ' « • .

Blech Í 4 : i . 22-5Y 1967.

.(in!German)

sStress corrosion aay be due to unsuitable material^, specificenvironments,.tensile and residual stresses hardness differences,tensile and residua! stre'ssssjhardness differences., presence of; • <-•A$ferrite (in some ,.typessof AI8ir4iO), and differences in heattreatment* Specific, susceptible materials and susceptible ..#'matgrial&= and respective environments are: Al -in NaCl^dins, andseawater'J austenitic stainless steels, in acid chloride* so Ins .;= r-

(;E 1-5), seawater, caustic solns.; Pb in Fb acetate=solns.; mild,aiitd low alloy steels in NaOK-NagSiOg/and NaQH olns. f Intfonel incaustic sdlns., molten caustic soda;'Pb compels, in hot aeratedwater; Cu in MlL vapors and'Bolns.r amines, Hg salts; Mg in, NaCÍand K chromat'e soln., rural aiid: mariue átin.., distdy' water;Montel in Auorósilicírc. acid; Tia in= fuming red HITCOV Stress", ; '•corrosion susceptibility canp be decreased by substitute, materials,'

' working below dangeroud atrás levels, and. special heat"treatments. Suitable design includes,prevent!on exf stress buildup,formation of compressive stress" on meial ¿urfaces (e.°g. byblasting), prevention of poorly accessible^locations with atagmantliquids or^deposit formation, "and normal corrosion protection

measures.-.10" -

t

t e . Bellot, J et al .'

IBTERCBYSTALLIKB CORROSIOIT IN NITRATES AND MOBILITY OP INTERSTITIALELEMENTS IN FERRITE. THE CASE QE PLAIN-CARBON AHD LOW-ALLOY MELDSTEELS. (In French). .

Mein. Sel , Rev. Met. 65:9, 607-625^ Sept. 1968. ,

, . The corrosion behaviour of plain-C and low-alloy mild s t ee l s wasexamined in. n i t r a t e solut ions as a functions of metal composition,surface condition,, and solu t ion pur i ty , by potent ia l and po ten t io -

I k i n e t i c measurements. The mobility of i n t e r s t i t i a l elements

(C.Jand N)-in t e r r i t e was examined using i n t e r n a l - f r i c t i o n and_ : e l e c t r i c a l - r e s i s i v i t y measurements.-' Crack propagation under constant

s t r e s a or progressive deformation, i n a n i t r a t e solution,.-.wasexamined and the in te rp lay "of electrochemical and mechanical

v fac tor i s discussed. 23 references. '29 . . Eelous, T M" e t a l ..";

EFFECT OP OXIDIZING AGE15TS OH THE CORHOSIOli CSACEIIiG OF Hal8N10TSTEEL. . '

Pro t . -Metals, 5:2, 186-8?; Mar.rApr. 1969.. ' , - . ' •

50. Bergen, C R

STRESS CORROSIÓN CRACK IHEIEITORS. . - -

Ü^S. 3,378,411 Apr. 1968.- " (Pant) \

Streps corrosion cracking of austénitic stainl^sis steel? in. chlorineatm.,is inhibited by.partially electroplating the oxide-coatedsteels with 2 g*/cm. of Ag, Fb, or Co or by partiality burnishingwith Pb. or Ag» Tlius, 304 stainless steel U-shaped bodies arecoated with 1»5 g. Ag/cm.2 in Ag cyanide bath at 7 v. and refluxedin CaCl2 soln. at 132"., lío cracks appeared for 120 hrs* as „ ,compared to 8 hrs.^for unprotected specimens. The. proposed mechanismis based on the strong affinity of the impurity ions for chloride ions

• J= which cone, at points of high tensile stress.

3 1 . ! 'BergenjV'C í ;E

)F- STRESS CÜRROSIOF GRACKIHG: MIGRATION OF CHLORIDE:INÍ ,•OXIDE :FILMS OS AUSTINITIC STAIIJLESS STEELE ; ; ^ ' ' i - . / ••

Cor ros ion 2 0 : 9 , 269-27j 1964. - / V'.Í ' •

In a number of corrodent-crack-susceptible alloy systems the specificion responsible for cracking is relatively large. THe corrosion,product formed in á corroding medium oontg. such, ions.wdiild imbibethem.. Under appropriate conditions,/due to their size, the largerions would, tend to diffuse to the region of the bxide film under

' highestf tensile stress where local high tensile stress j.n;the baffealloy would be reflected. It is postulated that stlie appropriateconditions for diffusion are. present and that- the migration'of theipn to which cracking is ascribed leads.to high local eoncnsi, in .

,: turn.causing; a local increase ;in corrosivity. Stress" corrosion r'cracking results where the phys., properties of-the alloy aré/suchthat crack propagation, can occur.. .JHie hypothesis was confirmed,

• with the-chloride-austenitic steel system. 'Chl'oride will migraite-: .reversibly under the influence of tensile stress. The presence of .. ,M will inliibit the migration of chloride up a tensile gradient andthefeimmurii.ty to cracking of tiigh-lfi aust'enitic stainless'steels isattributed to this effect. . " . . -

32. Berggreen, J . . .- '"."•'

APPLIGATION OF FRACTURE ILECHMICS- PRINCIPLES.TO THE IFVESTJ;#ÁTIOK OFTHE SUSCEPTIBILITY OF MTEIÍIÁLS TO STRESS C0SR0SI02I. CRACKIIIG . . • .( A S U R V E Y O F T E S T I Í E T H O D S ) . . • _ • - - . . . _ " - ... • ; •• , . •- /

Werkstoffe u. Korrosion, 21:8, 640-45-| Aug. 1970. - r ; "'_. •

The suitability was investigated of the yaripus specimen shapes,, .used •in fraloture.mechanics studies,. for the investigation of stress "corrosion susceptibility. The 3CB specimen was simplest^, only :onespecimen, being required per test, this can also- be used for , . --,determining the crack propogáti,gn rate and the state" of - stress most '" :"susceptible to stress corrosion cracking; no :data are-obtained on "iáiecorrqsilpnüiechanism. Tiie specimen is unsuitable '%ar highly ductilematerial-as the, dime-nsions. required would be-impracticable. ;45-references.

3 3 . / B e r r y * W E ,- ^ / V -. ; -~-/. '-;:-"; / ' : \ / -^ '/. % • ^ ' • ; " : V .-•/'. •.-:."••.-.•'•-• '- •

^ 30MB PACTS ABOUT STRESS CORROSI-ON OE.AÜSTEÑITIO STAINLESS STEELS/•• IN/REACTOR SYSTEMS. ^ ' ' , •-= :< ' .

Reactor Mater.y 7<1, i-13j(Spring 1964); . . ; -

Examples of s t r e s s corrosion cracking of austeni t ie s t a in less s tee l s.-.;-_ encountered in ¿stat l is l ied reactor system are presented. These

include: the Homogeneous Reactor,.Savannah River Reactor Plant., heatexchange a t J3apenhurst, Nautilus iionregenerative. heat exchangerSIW Reactor i l a n t , Superheat JSdvancé DemonStratipn Experimsnt,Shippingport°Pressúrized Tfeter fleactor, and Dresden control-rod

„ components,, Measures toi eliminate s t r e s s corrosion cracking;: ; suscep t ib i l i t y are discussed, including: reducing^stress l e v e l s , .

.•• ; a l t e r ing the chemistry óf the environment, cathodic protect ion, -- ,:.: changing the design or operating condit ions, subst i tut ing.al ternat iv-e

; . LHateriais-j—and*. _om.a_J.ang^range basis.y oinderstanding the mechanism..-':. ' of cracking.;..-Various" theore t ica l and experimental "attempts to analyze

; explain the cause pf s t r e s s corrosion are, summarized* ••'.;'.

3 4 . , . B e r r y , / W E 'if"- - '...'•••• :" ' I • '--

, • STRESS.CORROSION GRAGKI1ÍG-A NOlWECHlilCAL INTHÜDÜCTIOIJ TO ¿SE PROBLEM.. "

_. • DMIC-144*1^ • . Jan . " . 1 9 6 1 . : \ - - " ' , - ' -.:. ,' " . l'".-.' '• -• / . _. ,' ' ' '•'•_';. = .. _;''

: ? S%ress corrosion cracking is reviewed from S nontechnical vie%^.point#, .The recqgniLt£&a of this forcr of 'corrosion cracking is discussed» '\':\ •:..The environments most likely to= causé stress corrosion'cracking aré :

pointed-out for each alloy system...The effects of material.,- T

cOKpositioiiy ./stress, environment, temperature,-and time on'stress ;,corrosion cracking aré discussed, and suggestions are made ?forcontrcllingí these variables*. Tlie roles of protective coatings,

y iin^ibitors, ;.ánd cathódic protection in reducing crac'.cing susceptibiliigrare /considered. "A bibliography of some of the more recent articles on .//stress corrosion=crackingtis included. ;„ ;; c / ;

35. .Biefer, G J* Garrjádn, J G * : ' • ' - : / ; V . \

° STRESS CQRRO¿|EON CRACKISG TESTS OÍÍ SOMB/HIGH-STRElfGTE STEELS, ITSIiSGTHE ÜPSRL ( Ü é S . NAVAL RESEáRCH LABORATORTj CANTILEVER' METHOD^ ; '

•'' r = ~ ' ; - " ° J ; ^ V "- " " ' , - • ' " ' • ; " • " • - • " ••• • - -' : > ' •; .'• } ' "-'

Can., Mines B Γ . Tech, Bull TB114 31pi 196?. , „ ;/ •

The titlei/stiess corrosion cracking^ test has been used °atc the Phys.Metallurgy Division to tes t i;he¿cracking susceptibility, of a no. ofhigh-strength ^téels.. Result's ^re .reported which wereo6>taineá----'i'n

" 8trees cbrrosibn test^'on an \SffoMi. maraging'-steel/' •• '

"•-ü- - , » = °- - ¡.•' i- ' , . 5 s- 13 - - " ° = T, - =. . Goátd....

an HP-ÍÍ-4-25 s teel , a. Cu-Hi low-alloy steel 'developed at the phys.Metallurgy: Division, and a. 17/4 P3 stainless steel in each of theH900 and H1000 conditions. For each of these steels-, the tendency'to fracture;under dry.conditions was compared withj tha 1b resultingfrom immersion in 3.5?á ITaCl soln. in- the unpnlarized state* She .<•effects, of dathodic protection by 5083 AT alloy and 3n were also

; i n v e s t i g a t e d , * ' • • • ? . . r ; • •_- • . . - , ' \L-

3 6 ; B i r i e y , S S¿ Tromans,

STRESS aOEROSIOli- Oí1 3OáLAÜS5EEFITIC STEEL AKD.THE MRTENSITE •'

Corrosion 27i2,- 63-?lj 19Vi. \T ' . : \ -._ ";.= \ . / :• .-/

Studies have,been conducted on the fai lure of notched..and annealed - . ...rods of =304L kustenit io s t ee l 3.|ressed -in tension iri; aq. soln. ;, of,, .ÜS Clg "boiling a t . 154*. .The phases present.on tlfe actual fracture^

^surfaces were ptüdied by electron diffract ion techniques,1 . - . . . „Martensite etching' techniques were used to detect the presence bf •-martensite phases adjacent to s t ress corrosion cracks and to . '. _ :relate^ s t ress corrosion crack tópog. with. ,the morpho5.i of marteasite ._formation» 31ie observations were consistent with a'mechanism ofs t ress corrosion cracking involving formation of bcc a.1-phases adjacentto the crack t i p and subsequent.propagation of the crack throughth i s phase. Tlie possible mechanism by which a ' -phases ' i s formed ;

;.a"txd the ppssible -.mechanism of crack propagation, through: the; • .'a'-pliásé are both discussed. = • ' ,

37. Bol3,ant, VQ

Of STRESS CORROSIOif CRAGKIÍTG AÍID HTDRCSÉ1T EMBRITT-LEME^T. • , _ /'.(inJEtalian) ,; •"' ' ?-~,./ '• \ ,• V / , - ,- ; '^. . ' ¿-• •.

Met. Pta l . , 62:6°, 213-20? Juné 1970./ ./< "';"-'' '/ . '

Mechaniáms ó¿ delayed fraxt'ure as ir?. stress cory.caion and-I| , \ -.-.embritóblemeñt are considered in three phaaes; incubation, initiation^ ;/and pro paga t ie it, and "the alternative proposals are. illustrated diagramma'cicjdiágrámmaticaily. Results/of stress corrosion =tesíts; carried o it ./could be, expressed in ari equgitipn ana3.jogouS to the weibull. fatigue -equation; ((T-&,)^« t ;r=' "c («^«applied: stress,- (y-^* stress limit . ' *'OA delayed fracture^t » time torsipture,° k',« - numerical constants).".

=40

14 .-- c & v, '

• S 8 - B o n d , - A P ; D u n a a s , H - J •' .' :.'T '.••'"•'. ' ••

. EFFECTS.OF CQMÍ&SITION .0*1 THE STRESS CORROSION CRACKING OF FERRITIG^STAINLESS STEELS. _._. \ ,* ; . :; •. .. .....1

-: Corrosion-24Í10-, 344-52; 19;68,. ' ..

¡Stress eorr.osion t e s t s were made pn.Unbend and a x ia l ly loadedtensile-type^specimens iij boil ing 140° %Clg soln. The eatptl» •f e r r i t i c alloys téét.ed/contained Or"17-215, Ni and On did not .

. undergo s t r e s s corrosion cracking. .Ferr i i ie s ta in less s tee l s contg*\ 17-25fa Gr and up to 5$ Mo (no Ni, Cu, or Co) 'are highly r e s i s t an t to

- s t r e s s corrosion cracking*. A 17Jt> Cr a l loy , when Cold-worked, i s- -susceptible to s t r e s s corrosion cracking with 1»5 Ni, but i s r e s i s t an t

withVVlJ^. . Cr-lio s t a in les s s t ee l s that contain Mlj Cu,. or Co arér e s i s t a n t t o . s t r e s s corrosion cracking, in JfeClg only when l e s s thansome c r i t . amts.. of these res idual elements are present. Transgránularcracking of £ e r ra t i c s t a in less s t ee l s in boi l ing JJgClp i s not assocd..With the presence of retained austeni te nor i s i t caused by H

;_ • - embrittlement.-, .- ".' -¡. , • : , ._ ,-

3 9 , Bond, & P e t a l . . , ; •-.'•" .

.: . EESISTAUCE OF FERRITIC STAIÍJLESS STEELS TO STRESS CORROSION CRACKING.

Amer.. Soc.Test^ Mater*, Space. Tech- Pabl. 425, 116-24; 125-6? 1966.

Str-ess corrosion cracking tests-were carried out- on wires in boiling. - solns. of MgClg Ca(N0g)2»,s¿d NaOE. Austenitic stainless steels.

failed in 6-46 ¿in. in %Clg soln-i, but ferrite stainless steels "•"';_•'(types' 430 and .434) were Immune.under similar conditions»• They were,however,: subject to inter granular corrosion in boiling Ca(NO3)p -andNáOH so Ins. when heat-treated at 18.0G°F. Stressed specimens of .

.;•"'.- ferrxtic stainless steels: did not fracture in boiling 55^ Ca^ÑOg);?or 25fí NaOH solns., even after;heat treatments pausing intergranularcorrosion. Type 430 stainless steel is liable to pitting corrosion

, in boiling MgClg soln.,. but this is decreased by the addn. of Vfo Mo.

40. • Borgstcdt, BT U . ©t al ,' ,/ _•'._... . ., , "- '„ '.... .';.",-.

: DIRECT OBSERVATION OF %HE START OF ¿STRESS'- CORROSION CRACKING IN THE 'AUSTENITIC CHROMIUMLNICKIiL STEEL (GERMAN MATERIAL NUMBER 4988)' •• IN : ,BOILING MAGNESIUM CHLORIDE SOLUTION, (in German) . - ,\

Werkst. Korros» 22:2, J.21-5; Í971. --_. '

= The stress corrosion cracking of.the title st£el contgi C Ó.O6, Si 0.4,S 0.005, P 0.02i-Mn ll$ Cr 16.7, Ni 13j.2-_ lío_í.4,rV 0.8, and Nb-0.2^in boiling aq> MgClg'•&€-' 135-60° and stressed at 70^ tensile strength

" . . -.- • - -, ." = °=- ' . : - ' ' - - ¿ . ''' - 1 5 A ' ' , ' -\- •'.-*'•• C c n t d . . . . -

I

was studied microscopically and by elongation measurements. The directsurface observation.enables a,better distinction between theinitiation and propagation periods than the anal, of the elongationvs. time curve. The start of the, surface reaction, indicated by theonset-of the-H evolution.coincides satisfactorily with the cusp .Of' this curve. • . " . ' ;. 0 ' " :

41» .Bojfgstedt, H i et a l «. • . .' : • t . .

INVESTIGATION OF" STRESS CORROSIÓN OF IUSTEICTTIC .STEEIT AM), NICKEL• - ' A L L O Y S . • • _ . . . • _ • • ' _ . : .. ,

KFK-812 • 4 2 p , June 1968. .

42-, Boul ton, J . -

SOME ".ASPECTS PF. íkTERÍALS IM" ORGMIC COOLED REAÚTORS.

AECL-2640 9p. ; . 1966." -'•

The raauits'of* developments work'on the use. of 4 different sintered• AÍ products and Zr alloys ;in San-to az- OJff and IiB-40 ovg. reactor .' coolants' aré, summarized, The behaviour of.Zr. alloys now in use''" as fuel cladding and pressure tube.'materiar is discussed? in.detail inregard to operating ILife 'and liydriding susceptibility. 'Tlie stress

. corro'sion cracking? of stainless steel in Cl-cbntaminated- coolant is'examd1-. briefly». , • • '-, -• - ¿ ;

. 4 3 . B o u r r a t , • . J } " [ v H ' o c i i a a n n , 3 - •- j - . ' • '* ,..•••"'•- • .. \ . •

. • STRESS CORROSION IN. AUSTENITIC STAINLESS STEEL. ' -'-/..'

Mem. Sci. Rev. Met. 60,'551-63;. 1963. -

. Stress corrosion tests of-austenitic steels of -the 18/10-type inboiling 42$ MgClrt soln. were made, after different^surfaces treatmentsof/the stainless steel. Ad'dn, of 3.5$ ofinhibit?. stress corrosion inannealed' 6r work-hardHned steel.- c Steel, contg. 5.4?S Si; resisted thecorrosion for 1000 hrs. •'-''- a " / -

.- 16 -

44, Bo^ers.ock, E V • . .

3* A CRITICAL REVIEW OF STRESS 'COREO SI OH CRáCEIKJ AS ASSOCIATED WITETHE FFTF DRIVER. FUEL CLADDIlfG ¿ . . _

. ; " 'BBWL-Í1192. l • 28p. Oct. 1969.

45, Eoyd, W Z -.

; CAUSES OF STRESS CORROSION CHACKIKG,» '

. : Battelle Tech. Rev. 15:11, 5-1Ó; 1966>.

, Mech., eleetrochem., and surface-energy theories of stress corrosioncracking, and the influences of H in the various mechanisms, arereviewed. Electrocheai., rather than mech., factors are considered the

. most likely promoters of crack initiation and propagation.. ,18 references.

46, 'Boyd, W K . '

. , CAUSES OF STRESS CORROSSÍNG CRACKING.

Battle Tech. Rev. 15:11,, 5-10; 1966.

Various theories of stress corrosion cracking (SCO) were reviewed». It appeared highly unlikely that SCO could be caused by mech* means as

a result of high stress at the base of a pit of other stress raiser.There is strong evidence-to support the eleetrochem. initiationand propagation", as SCO might not be true cracking, in the sense of.brittle cleavage of the walls of the crack. According to the

. :: • eiectro'chem. mechanism theory, SCO occurred by dissoln. of the metalin every narrow area at .the apex of the crack with little or nodissoln. occurring along the creek,walls, -the same could be referred

-: to as exeptionally deep and narrow fissure* Although the abovetheory was applicable to most.of the All alloys; greater exptl. datawere needed to eatablish completely the eleetrochem. mechanism theoryof SCO in the light of and the extent to which the various factors,such as yielding of metals H absorption film rupture, and the chem.

-' environment in relation to crit. cracking potential, influenced theSCCf thus it could be furthur inferred that'artificial crackingcan be induced in most of the electrolytes0by the application ofimpressed currents." - /•- -

- 17 -

4 ? . Brabera, M.J

STHESS COEROSI Olí OF AUSTENITIC STEEL. . . . .• ' ; . •' ..,,

Ingenieurs'blad 37:15-16, 572-7; 1968* ' " ^

The mechanism of initiation and propagation of stress corrosion :,.'•fissures based on expts. and literature references is discussed.These fissures start usually fron a surface defect: inclusio'n¿crack, pit, or ciystallite dislocation line. More specifically,•inaustenitic steel the initial tear point-is located at theintersection,of 2 (ill) austenite.slip lines. . Electron microscopic photographs -

. show that the tear proceeds at 1st slowly along á slip-line, -,- .Subsequently,\a more rapid corrosion starts in.the direction-of =thecrossing slip lines located persion starts in the direction of the ;crossing slip lines located perpendicularly to the¡stress direction. "'The tear travels across austenite crystallite and contours theoriginal ferrite grains, which act as á tress,corrosion barrier. . ;Autcradiographs show that chloride, which promotes -.-the' stress • : .corrosion, can be present in large airits. around silica..inclusions, butdoes not-appear .at the hair,thin end of the fissure. The deternéntal •action of chloride increases with the adsorbability of the assbcd,cation, being progressiva el y greater with IJaCl, , GaGlg, and JiJgClg. : :

The corrosion breaking time decreases 'al"sVvrith increasing concn,-.of• acid and oxidizing coiapd., contact with coment, and the presence-of .finger prints,'even on stainless steel." H.ie-breaking tLme decreases .'linearly with the logaritlimic increase of the tension» .The breaking-time decreases also through moderate cold-working but. increases;. \through tempering and through strong cóld-rwórking which changes the •coplanar micro pattern of the crystallite into ao cláw-type one. [Ti\e.-breaking time decreases with Si concn. froza.O to 8-10^ but increases 'with further Ni content up to 40^ and, decreases again above this eoncn..Austenitic steel can be completely projected from stress corros-ionthrough" cathddic protections -150 mv., while .anodic polarization. v

shortens .the corrosion breaking tine. .

48. Brauns,. E; Ternes,, H • . , ' . - • ' • ='" • " -. " . 0 .'

THANSCRYSTALLIM! STRESS :(X)RBOSIOIT CHACKIHG OP AUSTEKI5IC CHSOitpJIi-- NICKEL, 5TEEL IK HOT CELOSIDE 30LÜTI Oils', ( in German) °;..5 . .;

Werkst. Zorros. 19 :1 , 1-19; 1968. : ',• ~ ^

The t r a n s c r y s t . s t r e s s corrosion -cracking of, aus t en i t i c s t ee l rods ofX 50r ííi 18-9 (corrospondingto AISI 304)¿ a f te r twice heat ing to - /1050° and water :q.üe-iching}'=was eStudied i n hot-coned. iigCl^ soln3. ...

/(^isufjly 459é s o l n s . , t b . 155°). The occurrence of s t r e s s corrosion.,CJíá'cK^ng for each s t r e s s a t unnoble p o t e n t i a l s i s ra ther sharply ,limited^ while on the-nobler s i d e , Btress. ccorrosi on. crac king increaseswith increasing life and pitting is intensified.

-18 - C o n t d . « . . .

decrease in temp, arid concn» as wellas increasing pH and increasing- . cold deformation ordinarily displace the potent ia l - l i fe curves moré

, _ of less strongly to more noble potent ia ls . A purely electrochém.. . mechanism of stress corrosion cracking of austenitic Cr-M. steels in

Jiot coned, chloride ;solns. i s not. proven, but appears, to be possible»107 references. .

49. Brenner, ; ,_P / . . . . •. . .

• • ' HMLISTIC-STRESS.CORROSION TEST; ' ,

fUte.ll'.> 23:879-86j 1969. 18pp. \ • .

50. Brunet,. ' S . «et a l . "'

EFFECTS OF VARIOUS FACTORS OH CHLORIDE STRESS CORROSION CRACKING OF. "• AUSTE3JITIC STAINLESS STEELS., (la French) , '

• " '. ' Eur-, Symp. Fresh Water Sea, Preprints pap., 2nd, Athens 4:46 (Pt-.3),7; 1967. \

.In this test program, a'stress to give 2.5J&- permanent -deformation,. • ,, Cl"*ions at 5.3g./I., pH 6.0, and 1500 hrs. exposure were used. The

' . influential factors were: l) the cation accompanying the CI"(corrosivity, Mg2+ >> Ca2+^ Ka+) \ 2) the presence of 02 in the .

" 'environment greatly increases the incidence of cracks (this effect ,may be by Og attack to form a. pit and the pit later becomes thelocus for the formation of typical stress corrosion cracks);3) .the addn. of Mo to the steel lessens cracking (probably byprevention of initial Og pitting). • •. '-

51. Bryant, R E? Gr^ot, J B • • '

• . -IMIBITI0IÍ OF CHLORIDPSTfiESS C0R30SI01Í CRACKIÍJ3 OF STAINLESS STEEL,. A L L O Y S . '. ' • , , ' .

Mater, Prot. Performance, 9:11, 19-23; Kov. 1970.

Stress corrosion cracking i s the primarj7- reason stninless s teel . -alloys' a r e avoided íih equipkent censtruction. Tlie susceptibility' ofvarious aus |eni t ic stainless steels to. cracking in boiling, 42$ =SigClg and inhibition,of 304 and 316. stainless steel by n i t ra te and

; carbonate additions by using f la t samples stressed HxthBrinel l 'impressiolis are discussed. T o nev, low-iTi alloys were found to be

= the.best choice for controlling stress corrosion cracking.

- 19 -

.52, Bryant, R E ; Greet, J B. ' / ' ', / . ' / - . - ,' • • - • • • '

'.." CHLORIDE STRESS CO-RROSIOIf OF VARIOUS STAINLESS ALLOYS AND . INHIBITION• ' . B Y N I T R A T E S . . " , - :

: • .. • " ""/•••" -• . \ : -:- • - - ' . ' ' . ; •• ' :

Proc. Conf. Natr Ans. Corros, Eng. .416-21 f 19 TO. . - : .

Different austenitic stainless steel alloys were tested foi- stresscorrosion cracking" (SCO) in boiling MgClo solutions: and in Mg0To-

solutions containing additions of KNO . Two austenitio stainless• •" • , . '• .• o • • - . ._ -,-..•

steel alloys'-containing-' 18-20JÍ Ui are innune to SCG in boiling" ti

y g J gIn l i ib i t ion of SCO lay K3Í0,, i s poss ib le "for the 300 s e r i e s s t a i n l e s s •' -s t e e l s . ' • " " . ' . '

53 . Burkaft , E R e t al •_•"_ ' -• • •.;._"• - . , . . . - - . ' •

EFFECT OP COLD 10RK "ON STRESS C0RR0SI01T OF TIPE 309. (24:12 CHROMIUM- ". NICKEL) AUSTENITIC STAINLESS STEEL. * ' . -. .- ' .

Corrosion, 2 2 : 1 , 21-22; 1966, . • ' " ' , " .

St ress Corrosion t e s t s of 24:12:1.4 Cr-Ni-MrL-S.i s t e e l in bo i l ing42% % C 1 2 so ln . and under uniaxial t ens i l e s t r e s se s .of 10000-30000/ob/in* indicated tha t f a i l u r e generally occurred above the vapour/l i qu id i n t e r f ace . Average t imes- to - fa i lu re decreased with increasingamounts of cold work, and branchrtype 'cracking"was observed.

54, Carter, C S e t al ' . - /

STRESS CORROSION PROPERTIES OF HIGH" STRENGTH PRECIPITATION-HARDENING "STAINLESS STEELS IN 3.5$ AQUEOUS SODIUM CHLORIDE StfLUTIOH. . • '.

U.S. Clearinghouse Fed. Sci . Tech. Inform. .AD;No.709044, 35p. 197Ó.

She plane s t r a i n fracture toughness E ( i c ) . and s t r e s s corrosionthreshold K ( i scc) liave been. detd. for the following high- s t rength ,pptn.-hardening s tee l s* 17-7 pH (RH 95p, TH 1050), PH 15^7Mo RH 95Ú,TH 1050). AMI 355 (SCT 850, SCT 1000),AM 362 (H 900, H lOOO). Ali 364"(H 850, E 950, H 950), 17-4 PH (E 900, H 100000,^15-5 M, a i r melted andvacuum melted CE 900, =H ÍOOO), PE ?.3-8Mo CE 9 5 O ) , and Cuátom 455; _ _r; =(H 950); .Correlations of K (¿sec) with service performance^ smooth-specimen t e s t da t a , and chenú co¿pns\ are discussed»

- 20 —

55¿ Cásale, I B

1 BOIII393 TEMPERATURES OF MgCl? SOLÚTIONS-THEIR APPLICATIONS INSTRESS CORROSION STUDIES..

Corrosion 23:10, 314-17; 1967. ~

Teinps. of boiling IflgClg solni used to detect susceptibility ofaus/fcenitic stainless steels to stress corrosion cracking have a-pronounced effect on the time to failure for these alloys.

* Available attn« b.p. data for spins, in the range 0.46$ MgCl? havebeen assembled and suplemented by new exptl* detns. An equationrelating b;p* and concn, for 40M5$£ solris have been derived.Because of varátions in water of'regent-gr&de MgClg.eHgO, it isproposed that measuring the boiling temp, of a aoln. is the preferredmeans both of detg. the igClg concn. and of controlling this concn».during stress corrosion tests. ' Consideration should be given to thegeneral use of a 45oO wt. fo MgClg soln. (boils at 155.0°) forstress corrosion tests. 18 references.-

56» Chaudron, fr

QUARTERLY SUMMRY (REPORT) N0;9(ON CORROSION OF STAINLESS STEELSUNDER STRESS), JULY 1-SEPTEMBER 30, 1-SEPTEMBER 30, 1964.

Work performed under united stattes-euratom joint research anddevelopment program. ' „

57* Chaudron* G - •

QUARTERLY REPORT NOf 18 (ON STRESS .CORROSIÓN OF STAINLESS STEELS,APRIL 1-JUNE 30, 1967* ..

EURAEC-1932 c ; 15p.. '., . :

Work performed under United States-Eurátom Joint Research and"Development Program. ; . , . -

The s t r e s s corrosion of s t a in less s tee l .was studied and the influenceof the s t ruc ture of the s tee ls and- the effect of a noble metal

- such as Pt addit ion to the s t e e l were determined. The part playedby martensi téánd austeni te i n s t r e s s corrosión was; noted... • Tlieres i s t ance ' to^s t res s corrosion of austeno-'martensite s t ee l s was

• . due to an electrochemical mechanism'caused by the nar tens i te andfixe electronegative protection 6f the= aus ten i t e . The addition

= of Pt= to a Cr-Nl type s t ee l in t ens i f i e s the process of, t r iangularcracking ..in boiíing ffplutions of magáesiuia chloride. Both corrosion

- o - . and p i t t i n g were' found ¿to depend on the physical^and chemical surface•' /condi t ions.

= " - - V - - ' - 2 1 - " : •'•' -"e . : •

.

Cheng, C í

CORROSION-CBACKIIKJ.QF TYPE 304 STAINLESS STEEL I N 'ffATER;COOLED REACTOHS.• . , . • ' _ . - " ' • ' ' .

Reactor. Technol., 13:3, 310-19j 1970. -

Nuclear pressure vessels, primary piping, - core components and. fuel-element cladding are subject to cyclic thermal and mechanicalstresses due to the high pressure and, temp, of the fuel coolant.When 304 stainless, steel is used as material for these.parts,potential intergranular corrosion failures due to ..the combined * ;action of corrosion and low cyclic, stress or high static "stress heedcritical evaluation. Reviews 304 stainless steel with respect to_.service failures other than chloride- or caustic crackiag in water-cooled reactors', various corrosion studies on intergranular crackingand the proposed laeclianism of inter granular corrosion cracking»44 references. ' ' - •" • ' • -

59. Cilial, YyKaspar, I£ ' '" .. •

. SIGMLS OF CORROSION DEPOSITS OK A SYNTHESIS GAS SATURATION COLUMN,(in German) _ • '- • . . . .

Werkst.1 Korros. 18:12, 1027-33?. 1967. . •

After 3000 operational hrs, á column of 10riQNi9Ti in.which gas iscooled from 1300° to 240° by water spraying, developed transcryst.cracks because of stress corrosion cracking which was accelerated bytensile, stresses on the sprayed side and by erosion isrhich Jirceded the.stress corrosion cracking at the inlet to the column. The deposittaken at various sites of corrosion contained Na+ Oil.30, Ca2+ 0*3-9.8JMg2+ 0.0.48j and CI". 0.11^. The corrosion "is due to the presence v

of 01" in the water, .the higli wall temp,, and the high stress inparts of the column. The stress corrosion cracking can be-avoided byusing Cr-3 "40$ Ni-Si, Gr-Jág, ferritic-austenitic ánd córrosion-resistent Cr steels. ' -- '*..'.'-.

60. Cihal, V; Kaspar, M -. r 6

STRESS CORROSIOIÍ CRACKIMG OF STAI1LESS STEELS, (in. Czech)

Sbornik Vedeckych Pracl, 13:1, 41-52; 1967. •." 3 !,

Failures caused by stress "corrosion cracking phenomena are describedfor a satn. column for cracked gas. The entering^gas,temp, in: .theeolumn is 1300°, th.c gas is cooled by aean$ of injected water so thatthe mean temp, in the lower part of the column outlet is /-O200e.

\, - 22 -Contd....

The satn. column is made from a steel sheet 8.mm. thick (18-20$ CΓand 8-llfo Ni, stabilized by Ti)¿ The most important causes of stresscorrosion cracking were (Í) the presence of chlorides in the water;(2) the high temp, of the satn. column walls which'favors eoncn.of the chlorides:at the walls as well as the stress corrosion cracking

.' progress, and (3) increased stress in certain parts of the columnresulting from the irregular temp* distribution. An increased Nicontent in. stainless steels will suppress stress corrosion crackingtendencies» Enhanced corrosion resistance "is assumed to be obtained

.with austenitic Mn-Cr steels contg. either a low content of Ni or-without M. and IT* ' • " .

61. Cihal, V; Poboril, F -

CHROMIUM-MANGANESE AtJSTENITIC STEELS RESISTANT TO STEES3 CORROSIONCRACKING IN SOLUTIONS OF MAGíJESÍtJM ANI) CALCIUM CHLORIDES, ( i n French)

Rev. Met. 6 6 : 3 , 199-208 ; 1969. .-

The resistance of various'austenitic. steels to stress corrosioncracking was examined in concentrated solutions of Ca and Mg chlorides.Cr-iah steels were significantly better than either Cr-Ni or Cr-rMn-Mtypes even when the latter were alloyed with ÍI; the Cr-Mn steels we'redeveloped primarily for their good ereep resistance. 30 references.

62». Clevinger, , U '

THE RELATIONSHIP OF IÍITROGEN CONTENT OF AUSi'ENITIC STAINLESS STEELSTO STRESS CORROSION. QRNO.438-17 ' •

EURAEC-2077 20-p, Sept. 1968.

63. Clevinger, G S .

THE'RELATIONSHIP OF NITROGEII CONTENT OF AÜSTENITIC STAINLESS STEELS. , TO STRESS CORROSION. (Quarterly Report."No. '438-18. -.

EURAEC-20821: 42p. June 1969.

6 4 . C le i r inger , G S , ,

THE RELATIONSHIP OF NITROGEN CONTENT. OF AUSTENITIC STAINLESS STEELS: TO ^STRESS' CORROSION. ' ( Q u a r t e r l y Report No. 4 3 8 - 1 9 . ) . _

EURAEC-2099, 20p.. 1969.'

-23 -

65Í ' CTévinger - f> . . . : ' , ;_. " - - ' • • , ' ' • •

. - 'THE••BELáíECpíojiilP 03?. NITROGEN tKOTEHI OF AUSTIÍÍITIC STillfLBSS STEEIS •..TÓ STRESS' COHBOSIOIí. (Repor t 438-20 Q u a r t e r l y Repor t No. 20)

EURAEGr2124\ ••• 2 6 p . . J u l y 1 9 6 9 . ; .. ' •.'•. •

6 6 . . C l e v i n g e r , Gr S . .' . . '.:•'• '^ ' \: •'•'-','•'

• RELATIONSHIP OF NITROGEN CONTENT OF ÁÜSTEHI.TIG STAI1ÍLESS STEELS: •TO STRESS CQRROSIQlf. ( F i n a l Repor t . , Repor t .Ha . i s e - i 1 . ) / . ?;• ?> „ ..

- EURAEC-2129 J 29p , ' Aug. 1969.- ". ' .'.' .• V:' \[ : ; -., ' . -

6 7 , C l e v i n g e r , G'Sj L y t t o n , J L. . : . : :

-. THE REMTIONSHÍP OF NITROGEN CONTENT TO THE SUSCEPTIBILITY AUSTENIT 1C'STAINLESS STEELS TO STRESS CORROSION. ( Q u a r t e r l y Repor t N o . l , June .

. 1 , 1970-Aug. S\f 1970 . ) _ , ] ° '

' TID-25554 | 13p. Sept. 1970. ' '" . "- \ • ' - ' - ' ' . • ' • • ' - • • ' • ' • • • ' • . • ; -

1-

- i1 " * . . , * " ' ' " -'' " ' ' : '68. Clevinger, G Sj; Lytton, J L. . . . . : ev

- ' . f - • • • • ' • ' ; . ' • - • . • . . ' - • ' • . " • - . ' * •

RELATIONSHIP, OF "klTROGEÍí CONTENT Ü?0-THE SFSGEPTIBILITY OF v •'.'••', AUSTENITIO STAINLESS STEELS TO STRESS ''CORROSION* (Quarterly Report

0(0,2 9 Sept. 1, 1979-Nov. 30, 1970). , - ^ ... ,» " : . =

."T2D-25664, 23p. Jan. 1971. '" ;

¡ 6 9 . C o c h r a n , RWi.Stgi.ehle, R-¥;-,'--•• : "••"'\-_:"i'''\:']. ° :.=";•'•".•---.." ' *- '

!• .EFFECTS OF' SURFACE,. PREPARATION IN THE, STRESS CORROSION CRACKING; ;0F• STAINLESS STEEL. | . -'J. .•"• : =V - ./' \, - ... - ' - -

. COO-1319-48 U 7 p . Oct . 196=6. - ;,

-•" 2 4 -m

70. Cochran, R Wj Staehle, 1-f

EFFECTS OF SURFACE PREPARATION ON STRESS CORROSION CRACKING OF TYPE. 310 STAINLESS STEEL IN BOILING 42$ MAGNESIUM CHLORIDE.

Corrosion 24:11, 369-78; 1968. ;

Effects of various surface prepns. on stress corrosion cracking of' type 310 stainless steel wires, in "boiling (154°) aq.. MgGl%, sonns,were studied. .Relatively large nos. of specimens vere usgd and the -time-to-breaking data follpwed. log-normal 'behavior. Mean cracking

- tiaes statistical scatter were obtained. Mean cracking times variedby. as. much as a factor ¡of 4. Hie effect of the various surface prepns.is related to the effect of surface roughnes-s on the" electrodeprocesses, primarily the redn« kinetics¿ -The greatest amt.. ofsatistical scatter was related to aa&ually prepd. surface prepns. ascompared with chem. prepns. Scatter was.. not proportianal to themean cracking tizne. Conclusions obtained herein on. the possibleinfluence of surface prepn. on cracking should be applied to other

1 alloy systems only where the controlling process involves electrodekinetics. • '-" , - "

71* Copson, H H . . .

EFFECT OF NICKEL CONTENT'ON RESISTANCE TO CRACKING UNDER TENSION OFM-Cr-Fé ALLOYS .IN CHLORIDE HEBIA.

- Rev. Nickel 23:3, 'GS^S 1962. .

,The lab teses (loc.cit.) wli ch result, in stress-corrosion crackingin.."alloys contg. C A5fo Ni. are more severe than service conditions.Alloys resistant, to- s.tress-corrosion cracking should also resist othertypes of corrosion, be easily worked, have acceptable phys. and mech.properties, and be com. available; By reducing stress, eliminatingthe chlorides and 0., and ,con-brolling the pH,c the stress corrosioncracking is minimized, to permit the substitution of austeniticstainless> steel for the over'J45$ ITi alloys. - -

72. Copson, H'Rj Economy,\G

EFFECT OF SOMET ÉN7I.R0NJÍÉNTAL XJJONDITIOííS ON STRESS' CORROSION- BEHAVIOROF UlCKEL-CHROMUM^IRON ALLOYSÍaN PRESSURIZED| 7/ATES. '

" ' . ' ' ' ' • . - '

. CONF-671007-4 "25p« '= '

-25 4

] ",í ' ;í

• l , t

W

i !

Jf,

it'ií

73,.' Gópson,' ,.H Hj ícónomy-, "C:.. -, ' V'-.'. • " " , • • . ' • : " •-•--"." ". :, ' 7"

Eí'FEGT 0F30J,ÍE; EMIHÓSiáEKTAL CQfflyíTIOmS Olí STRESS" CORROSION BEHAVIOR. OP.IÍIQiOiL-CifEOIvECÜH-IñON ALLOYSvIlíPHESSTJEEZED WATERS ; " . ' .. "

: Corrosion 24:3 , 55-65;" 1968. 7- ;'' ;;; \ ^ * , • ,. ; ,. • ;

Stress corrosión t e s t s in.-pressurized water a t 316°. were made ofperiods up to. 3000 h r s . , by lusing double Unbends- and double bend beamspecimens,*' .Gas compn.7?how thaWater and pH were ooíitrolled» - •'Tests-were made oii.com. heats tof • Incoriel'600;, Inconel :625, Incoldy -

• ,800i and- s t a i n l e s s s t e e l ;Iypes.304, 3041 and 347, Jnconel- á l lóy 600. ~',', weldments and some exptl.,/5onpns'. | some..•specimens 'were heat-treated»1 ':

..The comb lined act ion of high., s t r e s s , higfc 0 concri., and cracking ' '.? '";,'-. - -in the crevice; area i n al;l al loys-tested.- . ; Attack sever i ty increasjed;

with O concn. and man specimens'ainnealed "specimens.,- Sóln. heat.;.. -.'."' •-•treatment, l o » C content, or the presence- óf carMde s t a b i l i z e r s ' ;did not eliminate -tlié- :rattack* 'WeZ'd metal deposi ts :béhave¿L mórié. orless -like base metal . Yáriátibns i n cbmpn. within the normal? range1 .of; Alloys 600 were, unimportant», and differences' in belaavi or among

. tlie several a l loys tes ted were 'monor...'compared^ to -environmental;'"

.ef fects , lío at tack kas,observed in specimens s t r e s sed . a t S0$ 'ofroom temp, 'yi^ld s t rength , whe.n H const i tu ted the, gase phase or- . .when crevices were-absent. 3Jte combined conditions "causing

; cracking can.be considered an .ove r t e s t s , as they would nbii be .. : .- expected to the same extent, i n normal; operating pressur i z ed water '

.sj^stems. v In actual service where, eonen. . i s ' maintained "near, zero , • -

.•Alloys 600 heat exchanger tubing performs .we 1IV - 30 .references»7 ;,

74#-

í

H e t a l : " - ' • • • . - . • . " ' - . ' " ' - . • . ; ' ' - ' ^ ' - : • • ' . - / : ' '•'-'•'i' •"•'.,••..- ' ' • : - : ' . ' • • ' y

SENSITIVITY. TO"• Í5TRISS CORROSIOÍÍ ÁKD. IÍITERGRAITOLAR .ATTACK OF • HJGH •iíIGKEL AIJSTEiíITIC ALLOYS... /= • .!- .• ",;';;'-.: -;"'':'v ; 7 : . , ^ ; 'V ' ' /= . / -;' '"'. r-. ••-•''

Corrosion, ,22:10, 280-r7j: d i s c i s s i o n 287-9©j:\1966i-'-.. : " •-. :. r : . -. / •.

High-M a l l oys and various- analyses of Types ^P4L?, 316 and 347 as-'; ,;'well as sEuropean com. - s t e e l s of -similar analyses 'were / [ t e s t é d i i n ; • vdemineraliz; ed water at1. 350°--and' stescv a t 650°- for" varying per iods 7 7up t o 5 mos. High-Ki aus t én i t e s íwére 'Susdep t ib l e to i n t e r g r a n u l a rs t rSs s cor ros ion cracking d i f f e r e n t from the t ransgranular . ; -•"..••- '.''_ •cracking i n a u s t e n i t i c staihlfess^ s t e e l s . ; Tests,in-,650° steam slibw"crackingof high-Hi a l loys . , increased with l i g h t p l a s t i c deformation :.while 18 r10 and 10-25 s t a i n l e s s were uneffected* Severe ,

v intefgranular a t t a c k .was observed in" higii-Ni , a l loys c i n highlyoxidiz ing acid mediae \ A'structural'. ,element^iii-the-sV susceptible--•a l loys may be respons ib le fo r a t t a c k . ' . F b ' o r O'contamination oftest water cannot"explain the results reported^r wüich are at variance.with numeroud test and service iJesults\oB the samé.materia! inlike environments» .t- ; ,„"' ;•"'Mi k

Contd,

Fb or 0 contamination, of 'test water cannot explain the resultsreported, which are at variance trith nuneroud test and serviceresults on the same material in like environments. Pb was notdetected in later expets. and the-0 content was /. 0.003.mg./l.,-equal to the sensitivity of the anal, method, cracking observedsatisfactory industrial experience with Incoñel can be attributedio: low stresses. 27 references.

75. Corioü, H et al .

STRESS CORROSION CRACKING OF CHRQMIUllt-IJICEEL-iaON AÜSTEIÍITES IN'ALKALINE MEDIA AT HIGH TEMPERATURE. (in French)

Colloq. Mete Comu. Energie At. 8, 135-42; 1965. .

•The results of stress corrosion tests in alk» .media at 360° of 18/10type stainless steels and of Gr-IIi-Pe alloys (with 17% Cr and Nivarying from 10^77$) are given: NaOH and KCH are much more corrosivethan Li hydroxide-. • The morphology of cracking can vary greatly withdifferent test conditions t inter granular, transgranular, or bothlnter~and transgranular types of propagation were noted. 0 increasesthe corfosiveness, of the environment. A higher Ni content of alloysreduces the susceptibility to stress corrosion cracking.

76. Gouper, A S

MNIMIZING"STRESS CORROSION CRACKING OF AUSTEiJITIC STAINLESS STEELS.

Conf., Nat» Ass. 'Corros. Eng., Proc, 643-52} 1968.

Austenitic stainless steels and type 406 stainless steel, if stressed,• can crack in aerated CI solns. -J 100°F, but not in dry chlorides, .Bromides caus,e cracking, less readily, whereas iodides and fluoridesapparently do not crack austenites. All austenitic 18-8 stainlesssteels in ©11 metallurgical conditions are equally susceptible to CIcracking if stressed.above a. threshold level that is low enough to bepresent in most fabricated equipment, including claddings on low-alloysteels.- However, the time to crack increases logarithmically withdecreases in both soln* temp', and CI or Br concn. if alloys susceptibleto CI or Br stress-corrosion cracking are used, the probability oíscracking can be minimized by controlling exposure conditions»,. 'Also, equipment should be kept dry. ' Protective measures include:'•avoiding evápñ. and condensation conditions that can cone, halides,by using air-free water, : drying the equipment before .heating, endquickly completing any work that must be-done-under conditions that .can cemé, cracking; .Nitrates added to the water can inhibit stress-corrosion cracking, as ean.org. inhibitors if their concns..are

, maintained high,.enough» . . ; , .. y •

* ,' . ; ~ 2 ? - ••' . • ' . Contd.«...

Cathodic protection by applied currents and by Al orlsteel sacrificialanodes prevents stress corrosion cracking probably by causing changesin the sóln. at 'the metal surface'. This will not protect equipment insplash zones, vapor phases, or nonconductive environment alloys"with

" high"Ni contents are more resistant to stress corrosion cracking andmay be economically justifiable for .some equipment. Alternatively,férritic or martensi'tic -steels can be used to resist halide crackingwith some redn. in resistance to general corrosion. -12 references»

" ' • - * •

'77. Couper, A S

MNIMIZINC STRESS CORROSION CRACKING. TESTING AUSTENITIC STAINLESSSTEELS FOR MODERN REFINERY APPLICATIONS. • .

Mater. P r o t e c t . , i0*,. 17-221 .1969. . ' ' • .

To minimize the p robab i l i t y of s t r e s s corros ion cracking suscep t ib lea l loys should be avoided as much as pos s ib l e , a l loys should bedesigned to. minimize s t r e s s l eve l and the environment should becontrolled to keep.unavoidable halide solutions dilute, cold, air-free,possible --inhibited, arid, in contact for as short a time as •••possible»,12 references» . . . ' -

78. Cox, I B

THE RELATIONSHIP OF NITROGEN CONTENT OF AUSTENITIC STAINLESS STEELSTO STRESS CORROSION. (Quarterly Hep-;rt No. 438-9, July 1-Sept. 30,1966.) ' . ." - , - ' . .

EURAEC-1755 ' 18p.

79* T 3

.THE RELATIONSHIP OF NITROGEN CONTENT OF AUSTENITIC STAINLESS STEELS.'.TO STRESS ,CORROSION. (Quarterly Rep, rt. Kc.438-12.) -:-" ' -" •

EURAEC-1902 .' 14p. June 1967

8 p . C o x , •• T B ' . ' . - - - . . " . ' ' ' '•"' •'" ; . • ' •• '•-" •

• THE RELATIONSHIP' OF NITROGEN CONTENT 'OP AtJSTENITIC STAINLESS STEELSTO STRESS 'CORROSION. "(Quarterly Report No. 438-16..) ' ,• . - ' '

TÍD-24567 17p.. . July. 1968.

- 28 -

8 1 ¿ C G X , T B ; E c k é l , ' J F

• CHE. I ^ T X O N S H I P .OF:.-iíITROGEIí GOKPUí í O.P •AüS.Í'EIÍITrC : S T A I F L E S S STEELSTO STKÉSS-. CORROSIÓN:. • ( Q u a r í i e r l y Eep ' i r t N,-; . 4 3 8 - 1 0 . ) •

• E ü ñ A E C - 1 . 8 0 6 . . - , . - 2 4 p ¿ . ."v ; .,."'• " J . .' , - . . ' . • • : "t • • • • • . : . - - ' • - _ • , ._ _ _A _ . - ' . - ' ' • *

8 2 . C r o s s l . e y , - P ; A , . • • ,•/•;,-'•" ' . ' " . . - .

RESEARCH. Ó F . H f B ' BASIC ÜfÁTURE OF STRESS .CORROSIÓN POR VARI0I7SSTRUCTÜML ÍLLOYS AT...ROQM "ÁKD. ELE?ATED. TEMPERATURE.

J J'

I' t>

i, '•

¡ ' I i . . - : ; - •

p

lit.1

There .was prepd¿ a material composed of 2 layers of industrial 18/iOsteel, sensitive to tension corrosion,-, covering a: layer of 18/14stainless steel of very high purity. .' This composite materialallowed studying tlie resistance of high purity austenite. to. crackpropagation initially formed in the external, less pure, austenite.A microg. study, after prolonged keeping under stress in MgClgshowed the very clear stopping of the crack propagation at the'levelof the pure steel layer. Stainless steels of sufficiently highpurity are- rigorously insensitive to cracking under stress; theresistance of these very puré alloys*is complete, from "the point ofview of the initiation as well as that of the crack propagation.

.84. Davis, J A - ' • . •

• RESISTANCE OF 18 CHROIUM-iS NICKEL-2 SILICON STAINLESS STEEL TO --• . - STRESS CORROSION CRACK PROPAGATION IN BOILING SLáGNESIÜÍÍ CiJLORIDE.

. "Corrosion 26:3,: 95-8} 1970. • ' ' .

The crack propagation res is tance of a s t e e l cannot be detd. by.i.*?.% ociPfénikl'oii3.1 t e s t i ng procedur.es i f the s t ee l ; .is r e s i s t a n t to crack

i n i t i a t i o n , thus res i s tance to crack propagation-was de td . 'wi thpre in i t in ted , cracks» Two l a b . heats of s t e e l were prepd.", ' I withthe typ ica l 18-18-2 s t a in l e s s s tee l compn. and the other with

• e s sen t i a l l y the, same compn. except for high P and Mó, to make i tsuscept ible t o cracking. The s t e e l s were- roll-bonded together andsheet specimens prepd. i n the annealed, cold worked, and sens i t i zedcondi t ions . U-bend specimens were .prepd., half" of them with itiei .suscept ible s t e e l on. the tension side and the other half with ther e s i s t a n t s t e e l on the tension s ide . Tlie specimens were exposed

*tif bo i l ing MgClg ( l50° ) . Mien cracks appeared, specimens wereretained i n the soln . for a min. of 3-4 addnl. weeks to allow the

i* cracks t c propagate. No c r a c k s : i n i t i a t e d in-tlie 18-18-2 s t a i n l e s ss t e e l propagated to the in te r face and -stopped. No cracks wereobsd, that-propagated in to 18-18-2 s t a i n l e s s s t ee ly even for specimenstha t cracked i n 70 hr and were not removed for 5'month's. Sta inless

--• 'Steel is .resistant to crack propagation.- .:" • . .

85. Davis

«1 ''...Wilde., ;B E

' ELECTROCHEMICAL .¿ffiASÜRBÍENTS: Oíí AUSTENÍTIC' STAINLESS STEELS IN-' BOILING ÍIA.GBESIUM CELORIDE. . - ' • • . ' - • • • . •' ":' .- .

J . i i l ec t rpchem. S o c , 117:11, 1348-51; Noy. 1970.' ' . .

Eleotxocñemical measurements were made on AISI type 304 and ÜSS-18-18-2 s t a i n l e s s s t e e l s i n magnesium chlor ide bo i l ing a t lSO^C

Little difference in the cattibdic Tafel constant was noted- theobserved values being equal to that expected from a charge transferrate-determining step. ~r _ , ,

— ou "" L>oncu.». . •

Steady-state corrosion currents increased in the order type 304>USS18-18«-2 for the unstressed and the stressed condition. Analysis ofcorrosion potential vs., time and cyclic-polarization 'data indioatesthe presence of a film .on the corroding surface which affects thecorrosion kinetics* The presence of two .mixed potentials during cyclicpolarizatioftdoes'not, support (the nobler-metal enrichment concept of

.•••• '••• .crack propagation, "but rather, the film-rupture model* 20 references,

86. Davies, M.J et a l : '

STRESS CORROSION OF.IRRADIATED STAINLESS'STEELS.

•' A E R E H a - 5 0 1 4 '"."'• ' '• .

87, Denhard, EE, Jr,,' ; ; . '

STRESS CORROSION. RESISTANT STAINLESS STEEL.

t[.S.. .3^573,034, 5p. Sep.198?. (Patent)

A fuliy aaistenitic stainless steel is provided which readily lends•• "" itself to a variety of hot-working and cold-working' operations, which

' may be fabricated by way of common welding techniques, and which. possesses a combination of good general corrosion resistance, good

resistance to intergranular corrosion, and good resistance to. corrosion under stresses commonly encountered in use.' A preferred

steel consists of Cr 18, Ni 9, G 0.6-0. 85$, and Fe" tlie remainder.The steel is made-in an e-lee. arc* furnace. The setal is cast in theform of ingots which, aré then converted into slabs, blooms, andbillets,; -These, forms are reheated and converted info plate, sheet,strip, tubes, bars, rod, and wire in a hot-sill. The products •are further'converted into cold-rolled sheet and strip or cold-drawnwire and fashioned into various items. . .

88¿ Denhard,.-; E;E J r . , j Gaugh, R R - • .:" ' •- -

APPLltiATION OF AN ACCELERATED STRESS-CORROSION TEST TO.'ALLOYDEVELOPMENT. \ ' . . . " ', _ •

" Amer¿ .Soc¡í. •Tés^t, Mater.- Spec. Tech. Publ. 425, 41-5.0; 1967 ' '

Sampies^pJCcoffi,. and e x p t l . a l l oys con^tg. 30-50^ Ni were immersed i n ,' heated :SigGl2 $ 9 I n . , and s t r e s s e d . Welded samples, and welded .samples

- t h a t were bent across the weld, were inspected for cracks . An exptl*a l l o y , nominally 0.03C^20CrT45Ni-5Mh. had the bes t welding and ^ -aríticorrósion.properties, , : • .". • , •.

- 31 - :. '' Contd.» o.

J

• • • • • »

The alloy 1?-4, .HI,• after vheat treatment, was more resistant to stresscracking in 6$:NaClT0«;,5$-ISOAc* s oln; satd. with HgS than.the alloy 410,w h i c h had.been- tempered..' >'•'• • ' :-" • , - .

89. Despic, A R; Eaieheff, R G'

THE CRACK PROPAGATION RATE' IN TERMS OF THE ELECTROCHEMICAL MECAHANISMOF STRESS CORROSIÓN CRACKING OF METALS.

Compi. Rend., Acad. Bulgare Sci¿, 23í9, 1091-.94| 1970.

The rate of crack propagation in mechanically-stressed metals indirect"contact with corrosive solutions is discussed theoreticallyin relation to the electrochemical parameters of the correspondingsystems. Equations are derived for the mean; rate of crack propagationin"both, the active and passive" range of electrode- potential's,allowing for the'effects of'passive surface films in the second casé.The equations are strictly only valid for simple metals-, "but.by a

.. simple modification may bé applied to alloys as well.. 10 references»

92

90. Deses t re t , A; Wagner, GH ._ • -

INFLUENCE OF SILICON AND MOLYBDENUM ON THE STRESS CORROSION-CRACKING* SDSBEPTIBILITY OF AUSTENITIC AND AUSTENITIC-FERRITIC CHROMIUM-NICKEL

.• STEELS, ( i n German) • • • ' • ' . , -

Werkst. Korros. (Wei.nheir.) 20:4j 300-5% 1969. t .

Austeni t ic s t e e l s (fi 0 .03 , Cr 17.-5, Ni 12-15«5^X and a u s t e n i t i c - .f e r r i t i c s t e e l s (0 0.05, Cr 20-1 Ni 8-10, f e r r i t e ,30$) with addns. of2,5fo Mo and (of) 3-4$ Si were t e s t e d i n boi l ing so lns . of MgClg,CaClg, 5N NaCl, i n water a t 150, 200, and 350°, and i n steam a t 500°,Addn. of Si re ta ided crack propagation, while Mo acce le ra ted therecuperat ion of a p ro tec t ive . layer, esp.. on the s ides of •.• c racks , butwithout i n h i b i t i n g the crack formation i n coned, solns-. Sffects were .

.'marked in more d i l . so ln . and water contg.. CI, than i n coned.

93,

91. Desestret, A et al ; - , ,. ,

STRESS CORROSION OF DIFFERENT STAINLESS, STEELS IN CHLORIDE SOLUTIONSIN THE'HOT STATE. -• - / •

EUR-3764Í, 223p 1968,

-32- Contd.i.,

General corrosion and stress corrosion of austanitic stainless steelswas investigated in solns, at temps, -£300° and in steam ^500°.Eiglit grades of stainless steels were tested, 4 of which wereáustenitic grades and 4 austenitic-ferric grades, with sep, ofsimultaneous addns. of Mb and Si. The steels were .studied in % t

Ga, and NaCl solns. for the effects of phys. and. chem. phenomena onthe microstructure. Corrosion behavior was also studied in thepresence of water with traces of chlorides .added. Changes in themech. properties and in the microstructure'were observed, and theuse of chrome plating for. corrosion retardation as considered.

92i DeVries, G / .

.. CORROSION OF JMTALS BY MOLTEN LITHIUM. • .

Draleyr Joseph É. (ed.) Few York; Plenum Publishing Corp. 1970,pp 251-69 of Corrosion by liquid metals*

CONF-691007 .

A number of metals were tested to find *heir corrosion resistance tocontaminated molten lithium at 600°P and 900°F. The effect of lithiumon microstructure, tensile strength, and stress corrosion was. found.The austenitic stainless steels, Types 302,303,304j3i6¿347 and the

. ferritic-stainless steels, Types 446, 430r 405 apparently were notimpaired. Hardenablé stainless steels were corroded when hardenedbut not when annealed. 'Alloy steels showed increased resistancewhen tempered at 1100°P for 24 hrs* Titanium, molybdenum, tungsten,and' chromium showed, no evidence of attack. '.

93. Di-rian, J • . - .

STRESS CORROSION (in French) . - <

Bibliograpliy No.2. -•" "CEA»BIB-2 . •- - ' :•- '' • .; - "

^ A bibliography is presented with 240 references to.publishedliterature. The references deal with stress corrosion from both atheoretical and practical point of-viewj with regard to steels,-light alloys, other metals and alloys.

- 33 -

J

94». Douglass, D i a t a l • • . . ' ?

- ORDERING*, STACKING FAULTSj AHD SffHESS-CORROSIOii CHACEE KG IN • .AU8TENITIC ALLOYS. : . , ; . , ' ' • . .

Corrosion, 2 0 : 1 , 15 t -28 t j .1964. _• ' '• •;•-• • •

Benefits of increasing Hi in stainless steels, es-p, in the a absenceof JT, apparently are in raising the stacking-fault energy andenhancing cross-slip and dislocation tangling, thereby, reducing thetendency for preferential chen. or electrochen• a.ttack. IT isdetermintal because i t enhances short-range order and causesdislocations to remain coplanar. Any nonrandom solid soln. which ' .

Jdeforms by motion of groups of coplanar dislocations (low stacking-fault energy or strong short-range order) is therefore expected to besusceptible to stress-corrosion cracking. Hence, susceptibility . .cannot be decidedfrom stácking-fáult energy alone. Mie alloying - l :elements Cr,. Nb,c Ti, and Mo are determintal-becsáuse they lower thestacking-fault energy of austenitic steels and have a strongaffinity for interstitial solutes. : Tiie model proposed explains ;susceptibility dependence on compn., type of solid soln., heattreatment, and magnitude of plastic strain.

95. Duncan, fiB ' . . . .

STAUTLESS' STEEL FAILURE IHVERSTIGATIOff íROGRAií.. ( F i n a l Summary Report )

GEAP-5530 80p. Feb. 1968. .'. ;. . .

• E Ü R A E C - 2 0 2 3 • - • " .' ' •'' - " \ - ; . ' : - .

96. Duncan, E I -et al ' . - . ,' . . ."

-COEROSIOK" ¿F HEACTOH STHÜCTUÉAL ÍÍA.TEHÍALS. -.'.," . '

Experience with highly stressed austenitic stainless steel'reactorstructural components in water-cooled power reactors has=showh that'type 304 stainless steeí and other austenitic alloys are susceptibleto stress assisted intergranular corrosion .attack evea without-carbide- ppt. in tlie grain boundary. Two corrosion testswere ;

conducted to det». the relative susceptibility of austenitic-stainlesssteels and high purity alloys to train boundary'corrosion. Testing^"

c environments included boiling 5K HN03+T+ 4g.Cr°+/l. of water, arid,650°F. wat&r +0.1g.FeCl3/l., to activate intergfanulár Corrosion innonsensiiized stainless. sjt "

-, 34 - Cohtd . . ' . .

,High purity alloys are far more resistant to intergranular attackand.cracking than com. stainless steels in both test media(increasing Si and P content increases susceptibility to intergranularattack)". Intergranular corrosipn susceptibility of austeniticstainless steels is strongly influenced by the conch, of selectedimpurities rather than by variations in tire Cr and Hi contents.

u - intergranular corrosión susceptibility ,of austenitic stainless steelalloys is attributed to solute segregation of selected impuritiesin the grain boundaries.' A model was developed to explain theeffects of several variables on the intergranular corrosionsusceptibility of nonsensitized austenitic stainleás steels.

97," Eckel, J P; Clevinger, G 3 • -: • . '

• AfflffG OF AISI TYPE. 304. AUSTESTTIC' STAINLESS STEEL COJSTAISriMi, .NITROGEN AND. ITS UfFtuENGE OK STRESS-CORROSlOJtf GÍÍAGKI1ÍG. ... .. '

Corrosion* 26:8, 251-55; Aug. :1970. " . .. . /- . ,;r . . :-

; Type 304 stainless steel containing various anounts of-H was. strainedand subjected to an aging tieatiaent prior* to exposure to bpiling 42?S.MgCl2» Comparisons of susceptibility between.tinaged. specimens,.-specimens aged .et 154°~C and specimens aged'at. 200eC show, that ,..

•,.- •susceptibility is materially increased by the. aging treatment. .-- .. 1 1 r e f e r e n c e s . • • • . \ '. '••.-' • . ...

98. Eckel, J F et al .' ' - ''y,

. THE RELATroisSHIP OF HITROGEK CONTÍ35T OF A HIGE-POHITY 20:20 AUSTENITICSTAINLESS STEEL TO STRESS. CORROSION. '. ,

AD-639 " 2 5 p . 1966 . • ? •' : ' ; '

= Phys. characteristics of the alloy ás affected by N content weredetermined and rela'ted to promotion of. a ageing reactions whic.li

-_,' could be .associated wittustress corrosion cracking. Dilatpmetric ° 'analyses were performed as a function of H content up to 180°C andsolid-state reactions in this temp, range were observed* Thedesign of a dilatometer which pernits the appn. of a const, tensile " ,.stress is described. Internal-friction measurements were also

• ci&rried put up to 300° C. ¿ • ' , " " = " " ; °

- 35 -

': i'

o " •!

99V Edstrom, J 0; Fersman, |L A

CORROSION CRACKING OF 3TAÍHLE3S-. STEELS AND NICKEL. ALLOYS. ; : ;

, Tr, Mezhdumar.. Kongr. KorijO2:. Metal.,'3rd 2, 28/4«95; 1966. .. ""•; \ , " • . ' • •- •'••: . - • J ' " " • - ••-;•" ;\ - ' \ • . • -".-"•- . ."' ; :

Various-theories concerning'stress corrosion cracking"in f.p.c."/alloysare1 discussed, and observations regarding the effect of stacking . .fault energy and order transformations on the susceptibility of ^ ,- ••these metals to' similar faillure are considered.. Austenitic stainless-steels'of the 18-8 type, skinless steels, with increased Ni content,ferritic-austenitic steels,|;and Ni""alloys (600-, 800, INCOWEL X, etc) .were;, sub jec.ted to 2000 lir* -stress corrosion tests; in, 0 said., water, - .contgv 5 ppni. NaCr, [:pH- = 5, (pressure 100 atm. f.temp. 295° iii aspecially designed autoclave1', simulating-nuclear reactor thermal - $ ; -conditions» Radiation was s'iiaulated-by labeling- some of the sample 'alloys with 182Ta. Highest resistance to stress qorrosion crackingwas inherent to ferritic-austenitic steels," 231 alloys, and austenitic .steels contg*. 20$.Cr and 2 5 ^ | M . Ti-stabilized lé-8 steels were morereadily attacked by cracking 'fthan:.othex 18-8 alloys, while Mo increasedresistivity* No radiation effects were, detectable in 18-8, alloys • .subjected to 182Ta irradn. TL^e simultaneous presence of Fb and Mo '; :

in 18-8 steels eliminated comiiletely stress cprrosion- cracking'» IKCONEE.and Cr-Ni- 17-4 pH steel resisted cracking or pitting, .'aijct- thermal..

p.re treatment had no. effect upgn. corros i on behavior, lie springs, thatwere 'u$ed -for stressing- tiie salmpjes during_ the tests were made of Ni ., 'alloys'^OO. Some of them col l<kp sed during thetest "runs owing tostress corrosion cracking» Ex|jtl. data are still inadequat to providea comprehensive explanation offthe effect "'of = i and Mo upon 3

corrosion. ' 3Ji alloya are resistant to transcryst. stress, corrosioncracking, but are susceptible tj'p intercryst. cracking as proved by thefailure [of, the springs. '- ." ' Í _ , ,','•- ' '"'- . ' V' '"- ." ".

lOO. Evans, j?= R ' j j Read, R H

A MECHANISM FOR STRESS COHBOSIOHÍ

ARP-2 Í 52-18 9"lp. 1961S"

-Tlie stress corrosion cracking behavior of-304 stainless steel in MgClpat 140° was studied^ In st.otic pensile.' tepte, the time IKc failure ' " -decreased pi tlr appli&u- stress, iñ| agreement .with - previous work. No. ;intubation;!,period prior to the onset"of cracking' was aoted, wlaile - 'varying the time in soln»-prfor tl> the application of .stress had/ ',-no effect on; subsequefit-stress-iriajqced ^failure» Prestressiñg at"-'1-- .'various temps. =in air in the rang el 140.e.-500'e affected subsequent timeto'failure Wt 140"°' fn. • . - . - . - - . -- .

? i - 3 6 -C o n t d ••-.•»

Cyclic loading treatments had no e>ffect on time to failure, andthere was no evidence- of rapid cr -ck propagation characteristicof br i t t le fracture. ; Prior-deformation carried out at'various

: temps, reduced the susceptibility of.304 stainless^ steel.Mcrostructure was also found to affect cracking behavior stronglyjstrain-inducedluartensité .resulted ¡'in a marked increase in resistanceto failure,' I t was "demonstrated that the mechanism of stréss-corrosion cracking depended on ,the simultaneous -action of both¿lectrqchem. and mech. processes. -'\ • ' . . ' •

101. : Peldnañ,

STRESS CORROSION CRACKING OP^STAINLESS STEEL.

( D P - 8 8 3 ) P e b . 1 9 6 2 . -•'--. - \ . • ' •

( A b i b l i o g r a p h y ) . , | . -

1 0 2 . . P e r r y , B N . " ' • - " • -I- . '

THE RELATIONSHIP OP NITROGEN CONTENT 0 | ATTSTENITIC STAINLESS STEELS TO^STRESS CORROSION. ( Q u a r t e r l y R e p o r t Noi>2,.)

' - ' ' . ' ' \ ' , - • • '

' EURAEC-1322 (Dec. Í 9 6 4 ) . - -| " ;

.103. Perry , B N ~ • . . -. - |- :

• < > • • • • \ , • ' • • . . • . -

THE RELATIONSHIP OP NITROGEN COUTENT OP .AUSTENITIC STAINLESS STEELS •TO STRESS CORROSION.^(Quarterly R e p o r t N p . 3 . Repo r t 4 3 8 - 3 . ) . .•

EURAEC-1346 (Apr . 1966) . , ' ; : i • •... •

' • ' ' ' ' • • '•''-. ' ' ' . ' ' ' • * ' • - - • ' - ' ' t ' "

-104. Perry-j B-.N? Eckel , J P - ; ' ' . | . • , '.' • ' " - : • • ' - • ' • ' . . . ' . ! . ' i • . - -- • • ' - • • - - - .

THE .RELATIONSHIP OP NITROGEN CONTEIiT OP AU|3TEIfTIC STAINLESS STEELS' TO STRESS CORROSION. (Quarter ly Report No.438-8 March- May -1966. . • : ,

EURAEC-1676 . June= 1966.,, '- / '. }•],...-, ." •* ' " ^ .'

Work performed under uni ted s ta tes T euratbm ¡|5oint<.research arid, _/-, ' - -..development program.

Results of studies assóblated-, with dilatóme tiry of Ax Si type 304 -steel, wire "are.jeported.- A linear regression analysis was•performed \

\.on the dilatómeter calibration-, curve3 to obtain values Xbr sigma andibli» cénfidence interval at ' the mean tenperat^re of: each line segment -resulting'data are included* 'Specimens-pf aLltrided type 304 stainless

/s tee l weííe téstejd, in' the 'ítilatometer át 50 Etó| 170°. An analysis of . _,dxlatometer teBt resül°t3 is .'included with plates /showing irZremicrostructuré clíángéé* ; - % = " " ' \ -•-. , \ \ =:r

' " W ¿I ' ! ' ' \ i

J

1 0 5 . F o f c i r i , ; M N e t . a l . . . • • • • • ' ' } • [ V v > " • = . ' ; - - -' [

CREVICE*COBR0SI02I ÉM); PITTING OF STAINLESS STEELSAT.TEMPERATURES UP TO 100.°. ' .' • . _ • '- ' ' '"

^ poténtiostatic method Turas used in" an eléctrocHem. investigationconcerning the effects of acid-reducing properties-of ÑáG3rateat e™solns. under N'atm. on the anodic dissolñ.;of stainless/steele; Dataconcerning/pitting corrosion at 4t 100° are presented gr^hjicallyv •.and an evalutioh of these data i s included. . • , - • v v - - ,:

1 0 6 . F r e i d , M I Q i ? S u p r u n o v , V A ' ; - -" : ; . ; •. '• .'. '•": -.;" \ , - •:'•-•

INFLUENCE OF HEAT TREATMENT ON SHE CORROSION RESISTANÜE OF STEEL v : /KhlSNlOT (CHROMIirM-NICKEL-TiTANIÜTí) 15^ "stlLFÜRiC ACID SOLUTION., - •-;( in Russian) ' ,

, I zv . Vyssh. IJcheb. Zaved., iChim. :kliim. TetímolV"13:5;» 652f-5j 1970», "

- Tlié'heat t reatment of type Khi8N10T s t a i n l e s s s t e e l (Mn.4.31,.'-Si .0.52,Ti 0 .30 , C 0.06?$), "by holding for 10 l i r . a t 650-rl25e a f t e r quenchinga t 1080°, reduces the corrosion r e s i s t a n c e of the s t e e l towardexposure to 15fo HgSO. as evaluated by p o t e n t i o s t a t i c measurements. *-This r e s u l t s from the ' format ion of J S t - f e r r i t e . , The'ele.etrochem.. . J . ;

i n s t a b i l i t y of TiC a t p o t e n t i a l s ¿fc 0.5V leads to, the formation ofa c t i v a t i o n d i s c o n t i n u i t i e s . The magnitude¡.'of the anodic po l r i za t ion ,curi*ent d e p ^ d s on the quantity, of sepd. ca rb ide , which, i n turn i s ; •á function of the thermal treatment." . : - ; . ,., . ,;=, '•'•'> "'•"'•'•

107* . F r e y , J H^ S t a e h l e , R'V •."_. , , '"._, " . , • ' , / • • • • • . . ; - .\:¡ ' .

' EFFECT "OF ÍTEMI)ERATÜfí|í, STHESS:ANIÍ ALLOY COMPOSITION Oil THÍ ROLE OF ". STRESS -COHROSÍON CRACKING I N F é - N i - C r ALLOYS-. . ^ '.' • - I- -

- * • - : ' " „ - . - • - . . - J ! ' " • l l ' : ' • - " ' ' • • • -- "' ' - ' *'~ . ' ' : : : ' V ; : ' ! ¿ \ : ' ' . ' - ' , ' ' • • • - " • ' •

High, purii3y water corrosion of? metals, 35-tlj 19B8* '(Met. i . , 6909-72•. . , - o í s l o . •; / ' ^ : - - . . . • - ; ; ; "= . , ; ; - • ; . ; • . - " / - \ - ' • ' • - ' . : ; % -:^::- y - ' T . \ * .

a- Studies tp assess the effject of temperature on stress corrosion" *...•cracking pt Fe-Ni-Cr alloys s re described. 'EJiqaeriments. were*conducted.in a circWating, .high-temperature^axitoclaTesrayvstem icsr^tempeiature

, range of 49* to. 288^0,(300'to =550°F)°fc= sodium chloride concentrations "of 10 ppnij and 0 concent rations of 10-18vpgm« CM^La^gás^ moat rapidand progressed at-approx;c the^ same, rate in= a f egibn° of 177 t<y\ 260"C.

,; - At the; higher temperatures there was a. strong tendenby for clackingprocess ,to be, stifled,i^resumably "because G£\-tiiK^buildup of Tóxide.

/films and-the associated írillibition of slip step'emergence. Grackí ng "; times for specimens, exposed to boiling MgCln ** 154°C were,.found to be°

in the same í;ángeo as.'thos^rfor the dilute scolutíó¿s at ; the saiaev- »,,.' ' - t e m p e r a t u r e , ' b - ^ . _ . -. - " ! " - - . - ; ' " ' " = . ' *._ -0'- .'':!;/"• = ;-_ •- '" • ", ' i ' . ' " "'. : ? . " ' ? "._

- 38 -' Í-'Ú

1 0 8 . • F u g a s s i / P j

EFFECT OF HEAVY- METAL i-OÜSh-Ólí SUSCEPTÍBILITY'OF .AlSl' 4340 FOIL TO- STRESS • COERÓBIOIÍ CRACKING IS DILUTE AQUEOUS HYDRGGHLORIC ACID .

S O L U T I O N S * •--% -..*.-• "•".".• .= . : •.- ,•;•; . • .

Corrosion, 16:3, 118-120; 1970| / , * '

"The time-required for the cracking of AÍSI 4340 steel foil in diluteaqueous hydrochloric acid solution pH-1.5, is greatly increased bythe presence of small amounts Of 0d++ and Pb++ in concentrations•"fis.lof as I6~4M. It is- suggested that these heavy metals, whosesulfides have'solubility products in the range, 10-29-10-26t form

^sulfides more insoluble at pH 1.5 than can be formed by certainareas, present en the1 surface of the foil. Sulfidéd areas on thesurface of the foil are assumed to. accelerate,"the absorption of 'H b y t h e f o i i l . . V . I - " - •'• . •. - -' ".:- • •" '-•'• •'•' - '•'..• •-''''''

1 0 9 . G a u l , Q G e t a l • - - : . . ' • - .

•-.".. ; STEESS OORÜÓSIOÍÍ OF TIFE 304 STAIIiLESS. STEEL I i i SliáULATED SUPERHEAT•••"•"• R E A C T O R E N V I R O B M E H T S . •'• '.'••'...'-'." ^ ' ' . - ' . . ' •'"

GEAF-4025

.110. .Gerasimoy, V I . e t ; á i . •- .- , ': : •: - . •• . • ' • .: ' , V

CORRELATIOií BETWEEií TfflE IIÍTEECRYSTALLIKE CORROSIÓN AI© THE CÓRROSIOífCRAGKINff TEííDEírciES- OF AUSTElíITIC CHROMIUM 'NÍCKÉL. STEELS. .(.In-Russian) •

Piz»'"Khim*-Mqkh-i Mater, 5 íS ," 165-9; 1969»;, . - - i ; .' , „ " ". • <\ '-:_-. •"•'-.

_^ AÚ^tenitic s t a i n l e s s s t e e l s ( EP350 and E1I8IÍIOT which after , c e r t a i n .v. " ; hea t . t rea tments ( e . g . , holding for 20 min. a t 1080° followed by;' 2 :hrsV '.

• \ at. s>500) show.a strong1 tendenby tewards in te rc rys t , , ¡ cor ros ion . \; cracking in r water a t 300-50° and 115-168. atm.-pr i n a Z5fo ííaCl-0¿5^ / : ;.

a t ' 2 0 0 ? , 16 atmí¡f The 'overal l corrosion r a t e i n the NaCl' ,•solnsh i s ^ g r e a t e r than i n the:..water. ' Tl ie-bracking may be e i t h e rt r a n s c r y s t o r i n t e r c i y s t . ¿ ° " • / - ' - :'•'•

- 39 .

Ü', Ill* Gerasimov, .7 If^yabchenkov, A V

THE EFFECT OF pH VALUE OH THE CORROSION CRACKING OF AUSTENITIC(CHROMIUM-NICKEL) STEELS. (In Russian) • -• ._ • . '

Zashchita Metallov, '4í4, 44Í-444;, 1968.

A study was made of the effect of pH value • of chloride solutions ";on the resistance, to corrosion cracking of two austeñitic Cr-Nisteels? (i) KI1I8NIOT, 18:10 Cr-Ni<Ti-stabilized steel, which has good.resistance to corrosion cracking in Concentrated CI solutions; and ,ii)\Kh20N45B', 20:45 Cr-liFi Nb-stabilized;steel, which at pH 4-5 is •-insensitive to this type of attack. Tests were conducted inj; . 'autoclaves at 200°C andj.6 atm pressure in 25^ NaCl + 0^5^ K^CrgO^-,with the pH adjusted by ."HOI and HaOH additioné to values ofl,3^5j-?|9,li and 13, Specimens were examined at x? aiid x 25., ?

mághlíications after 1,3,5r?í and lOh, and then after intervals of5h for s total period of 300h. Scilutioiis were changed, wherenecessary, to .keep the pH value constant. At p'H i-5 steel i) was : .subjectedyery rapidly to corrosion cracking, i.e. in l-3h.Resistance improved with increasing pH, and pH 13«the first cracksappeared only after 50h (this agrees with the data of Hoar andHines). The attack was tránsc.rystalline^ and pH liad no effect on theform.or distribution of the cracks» Steel ii) was resistant to theseconditions under stress at all'pH values and, no crackling «as found'in 300h, Steel ii) may be used for struc*feüfes operating in 'aggressive media over a wide range ofpH. /The reasons for thé occurénceor non-occurence of cracking are briefly-discussed»

i t l , i!

m

112. Gerasimov, V If Ryabciienkov, A V ' ; & ;. \

STRESS. CORROSION BENCH TESTS OE CHBîIUM-18 NICEELîO TITANIUM•STEEL KliiaNlOTÛNDER-HEAT EXCHANGE.. CO pITI01JS. : ( in ,Russian) f

-.', Éizé-Kliim. Mekh._ Mater.' 6:2# 38-421 1970. / ° f ' ";

Tubes made of s t e e l XhlSHÍOT undergo corrosión ;cpaeking a f t e r ", -. -300-400hr of t e s t i n g a t 200-310* ih 'wa te r Cdontg. 55-75 mg CI xóns/%,.and 0 .8-2 .0 mg0/í.. F i r s t , corrosion p i t s 1 5 - 2 0 ^ ^ deep appear a f t e r

; 100%r of tea t i n g , and the 1st corros ion cracks , a f t e r 400. hr,~ The °g r e a t e s t no., of c'facks develop i n t h e e v a p n . zone on the pipe- elbow '

, . wliere^ the* max. t e n s i l e s t r e s s e s rekch 20 .kg^/mm?. The appearance ofcorroáion" craéks on= austenite= s t e e l p ipes i n the presence of ah ~\; .inténsive^Kéat /£ lux ( i x 108 kcal/^n^-hr/- arid t e n s i l e s t r e s s e s of - * =order 0 i 7 - 0 » 9 - ^ 8 does .not depend on the. phVs. na ture of the,heat"c a r r i e r (higK pressure .«water vapor , -o r liq.. me ta l ) . •"-. " '

i - 40 -

113 3-erasxmov, 7 V

/CORROSION OF REACTOR MATERIALS: A COLLECTION OP ARTICLES.

A£C-tr-5219. • 1963. - ' . -

Contains á collection of,29 papers pertaining to the corrosion of¡.reactor materials and is divided into the following 5 sections:l) Method of corrosion and electrochemical investigations in water athigh temperatures and pressures; 2) Influence of- the watercomposition on the corrosion bf construction materials; 3) Corrosionunder stress: 4) Intercrysta.llite corrosion; 5) Corrosion of reactormaterials*

114.. Gerasimov, Poppva K A

;AN INVESTIGATION OP THE 15ECHANISM 'OP THE CORROSION CRACKING OPICrl8N19T AUSTEFITIC STAI2TLESS STEEL.

AEC-tr-4684 . I960..

The effect of mechanical stresses- up to 33-3 kg/mm on the kiniticsof the electrode processes of ICrl8N19T steel was investigated indistilled water, 0.01 F-sodium sulfate, 0.001 Ni nitric acid, 0.001If sodium hydroxide and 0.01 - N sodium chloride. -It was shown thattensils stress on the stainless steel has no effect on the rate of.the cathode process and the dissolution rate of the steel in thepassive condition, Tensile stress on a sample in solution of sodiumchloride, in contrast to, the other media investigated, has asignificant' effect on the Sinitics of the anode process by compressingthe, region of the passive state, and.by increasing the dissolutionrate of the metal. An increase in chloride, concentration in solutionhas an effect an the kinetics of the"anodic process which is analogousto that obtained with an increas-e in tensile stress on: the metal.On.the basis of the data of.the, electrochemical investigations, ahypothesis was advanced on the mechanism of" the phenomenon of thecorrosion cracking of JCrl8ííl9T austenitic stainless steel. Methods.of calculatiag the safe concentrations .of oxygen and chloride insolution from the poi.it of view of corrosion cracking were noted on thebasis of the data of ,the electrochemical investigations.- . • -

- 41 -

115¿ Gerasimov, V V et al . • . s . .

INFLUENCE OF PROTECTIVE METALLIC COATING-'ON THE .CORROSION CRACKING. OP•'.STAINLESS STEEL, (in Russian) .

. VÍiyánie -Zashchltnykh Metallicheskikh pokrytij'na korroatibnnoe. rastreskivaniy nerzhaveyushchej atalli. Zasheh. metal, vol. 6:4, '

p. 420-424; 1970. . ' . . i

ü\-\

h>: i

116. Gerasimov, V V et al

EFFECT OF PROTECTIVE ME-TAL COATINGS-Olí THE CORROSIÓN CRACKING OFSTAINLESS STEEL* (in Russian)

Zashch. Metal 6s4, 420-4; tó70e .

Different coatings on 0klal8N10T steel were evaluated as to^theireffectiveness in providing long-terfa protection against corrosioncracking in a CI- coatg* environment at elevated tempi, under stress»The coatings evaluated were flame-sprayed, plasma-sprayed, and

s hot-dipped Al, plasma-sprayed Alumel (Hi+ 2*5$ Al), plasma-sprayed"Nióhróme (iQi 20N 80)j electroplated Ni (from a Watts "bath), and -chem. deposited Ni (from acid soln.). Both of the sprayed Al coating,A/10Ó- t4í- thick, afforded the greatest resistance to corrosion .cracking^ while also providing electrochem. protection to the steel.Annealing of.the sample after coating, with Al, for 2hr at 510, 700,.or 870° increased tlve resistance to corro si on. era eking fry at íeaát'afactor of 2j annealing temps, above the m.p.. of =Á1 (.600°) lead to theformation of a thick P^3 .S) and brittle ihtermetallic layer, wMohtended to propagate crapking into the Al layer arid thus, was -inferiorto the sprayed Al coating annealed at 510°. . , . . ' .

117. ( Gerasimov, V V- et al '. . ! ,; - " * ,. - ' - " . . -. /

THE EFFECT OF THE CHLORIDE AND OXYGEN CONTENT OF-.v7ATEB O N STRESSCORROSION CRACKING OF AÜSTE1ÍITIC STAINLESS STEEL. .

ii

Ip¡III

Teploenergetika', 15:6, 40-41; 1968. ' ; ~

Data are giben on stress corrosion cracking sensitivity.of austeniticstainleá^ steel (lKhl8N10T,, 18:10Cr-Ni, Tir-stabiized)-in water ofvarying «fV and 0 contents at 330°p "and, 130-150 atm. 'With an 0 contentsof 0.1 ájj^í;. cracking of stressed specimens did not occur even when, "'the Cl~ contement is 1000 mg/i; with 0 at 5 mg/l'f with 0 at 3 iag/l. .cracking occurred when= the1 01" conteiit was 0.1 mg/l. and for.theimalgenerating plant with ,ttíe ¡lattes 0 level, the CI" content mustieZ. 0,1 mg/l. 'In plant with a 5l#rels of 40iag/l¿. the safe; Clr 'level i s ,

/ 1 . or less . ' • " - , " . . c ,' £ - "

• . - , • ' • - - • - 4 2 - " " / < - • • " - . . . . . - J.-'--. ' •

hi

118. Gibson, S P. et al, . .

• • ,.' CHLORIDE STRESS CORROSION CRACKING IF THREADED 300 SERIES STAINLESS '' • .• STEEL COMPONENTS. . . •' . ''" . .

AECL-2878 1967.

The seri'ousness of chloride stress corrosion cracking is discussed,along with plates showing corrosive effects of failures in high

,-. ' • temp., water system. The source of chloride, in soine instances, was- ( traced to ehlorofluóra org. compds. used as lubricants for assembling

the threaded compountsV * . .»

119, Glazkova, S M et al ' •- "••'•STRAIN-AGEING AND ITS EFFECT ON TEE TENDENCY OF AtJSTENITIC STEEL TOCORROSION CRACKING, (in Russian)

The effect -of strain-ageing on the corrosion resistance of austeniticCr-Ni steel was studied in relation to the strain-ageing mechanism.

. Tims after working and ageing at 20-350°C a sharp 'tooth' indicativeof" strain-ageing appeared pn the stress/strain diagram and the defodeformation resistance increased? at the same time there sas an

- . 'increased tendency towards corrosion clacking. These effects were ,. • attributed to the pinning of-dislocations by point defects,

constituting intersitial- atoms and possibly vacancies* 11 referenoes»

120. Graf, L; Springe, G ( -

CAUSES OF--STRESS CORROSIOIi OF STAINLESS, CARBONSTABILIZED AUSTENITICCHROMIDM-NICKEL" STEELS, (in Merman) ;. ' • " . .' '--

Werkst. Korros. (Weinlieim) 20:4, 23-7; 1969.

Potentiokinetic current-potential- curves -were detd. for steel W.Nr.4306 and pure Cr, Ni, and Fe, :in MgGlg spin, . at 142^. . Passivity of

• the steel was demonstrated and the absence of a -Flade potential and;the low c*d. in the^ passives region "are • discuss ed.v Expts* underconstant deformktian showed the effect of rate of:deformation on crackdevelopment. The relations between pinhole"corrosion and stresscorrosion cracking are discussed. _ •

121,- Graf", Lj Springe,; G- ' .->-•'- :" . ;v ' • > ~ - ;'

• R E L A T I O N S H I P O F DYNAIvIIC S T R 4 I N I N G AND P I T T I N G EXPERIJIEÑTS TO I N T E R - . 'P R E T I N G . T H E MECHANISM OF CRACKING I N A U S T E N I T I C S T A I N L E S S S T E E L S . • ..\ '

P r ó c . C o n g . F u n d a m , A s p e c t s o f S t r e s s C o r r o s i o n C r a c k i n g , 3 3 5 - 3 4 0 $. - "*• 1 9 6 9 . - =- '^.-.- - -: •..-;;- ;- "'•"-. - ' - . ' - . •.- . . : ' - ; ' •- _ ' ; ; ' •

- 4 3 -Contd.«.

1t

The causes of stress corrosion cracking of" air sustenitic stainlesssteel in MgClo are shown to be the same as /those in homogeneous,honsupersaturated nonfer-rous alloys, such as. two :solid-solution effectscombined with a pronounced electrochemical process inside the cracks-The former are intrinsic properties of solid' solutions, therefore only

; "tlie orgin of the cáthódic areas on -tlie. crack..wállá were to bedetermined because the potential, difference" between the flowing crackroots and the . nonflowing crack wails is riot sufficient» .'STonstraining^material is shown to form a stable/protective fxlni in boiling MgClgwhich, moreoyer,. acts' cathodieálly. on the arack.walls whereas the .plastic .flowing:crack-roots.are. not passivated and act as anodes',with.the help of schematic c'.d.-potential diagrams, the potential rangeis shoWn in which stress-corrosión cracking can occur* Experiments inwhich pitting -was allowed to commence j>rior to stressing showed that . ,jthe onset of cracking, once stress had been applied, was significantlydelayed. These pitting experiments show the importance of competingelectrochemical processes and also verify the electrochemical natureof the cracking. 13 .references, " '

122. Graf, Lj Springe, G

OE DYNAMIC? S'TRAIKÍIG A10)/EITTIÍÍG .EXP1RISÍEEÍTS 10ÍHE MECHAÍTISIÍ OF CBÍCKÍNG. IN AÜSÍEEIÍITIC STAIÍfLESS STEí5,S:. ".'. •[

;Proe* Conf.,. Púndam. Aspects Stress Corros, .Cracking 335-41 % 1967,

The causes of stess "corrosion cracking of.an'austenitic stainlesssteel in boiling MgClg are i¿ie .samé a3 thoáe ín homogeneous,. non-',supersaturated,• nonferrous alloys, i.e., 2 solid sbln. effectscombined with a pronounced eléctrochem. process inside the cracks. "The former, are intrinsic properties of solid solns., therefore only.:,the origin of the cathcdic areas on the crack, walls were to be.detd»,.because the potential difference'between the flowing crack roots- andthe. nonf lowing, crack walls is not sufficient, lions training material"forms a stable protective film in.boiling lágClg which, jnoreoyer,' actscathodieálly oin the crack.walls., whereas the vpláS:tic flowing crackroots are not passivated and act as. anodes.- : With/the help of'.schematicc.d.""potential disgrams, the potential range" is shown injj?hich stress.'.-corrosion cracking can occur, Expts. iñ which pitting was. allowed .to. commence: prior to stressing, showed that the onset, of cracking, .once,stress had been'applied, was significantly delayed.: These pittingexpts. show, the importance of' competing electrochem. prpcesse.s arid, also-verify the electrochem. nature of the crackings " ; . *. . -

r.

123. Graéfen, H • ' -

NEW RESULTS OF ELECTROCHEMICAL STUDIES OF STRESS CORROSION CRACKING. AND THEIR.PRACTICAL APPLICATIONS, (in German)

. . Corros. Soc. 7:4, 177-95; .'1967. • . . ^

- Results are given of electrochem. investigations of str.ess corrosipncracking with perticular references to mechanism. Data are presentedfor intercryst.- Stress corrosion of unalloyed C steel in Nb3"-contg¿cracking of" austenitic Cr-Ni steels in Cl""-contg. media, in HgS0¿» eto»

. With unalloyed steel, there .is a gr^.in activation potential boundaryor cracking sets'in the potential decreasing with applied, stress inNO™"" media; in alk. media, the "potential range, in wh'ioh crackingin likely to secur very, small with stress corrosion sensitivity beingsuppressed by anodic protection. The ievel of the activation

•. potential in áustenític steels in CI"- bearing media is crlearlydependent on stress load; cathodie protection for suppression oftrariscryst. 'cracking'is"also dependent of the level of appliedstress, higher stressing moving the potential to neg. levels. In

- . the' case.of transcryst» cracking of Cu-contg» austenitic stainlesssteels in H?S,O¿ media, Cu-contg. protective .layer formation, is

important with local failures Being facilitat-ed by applied stress.

124» Green, R J et al •

EFFECT OF GRAIN SIZE ON INCUBATION AND PROPAGATION OF STRESSGORROSION CRACKS I1T TYPE 302 STEEL. . ''

Corrosion 24:5, 137-8j 1968. •

The.effect of grain size _on the incubat-ion and propagation of stresscorrosion cracks,, in annealed type 302 steel exposed to 42 wt. $MgClp was investigated. The incubation period was grain-íaizedependent, and-' incubation..tines of 15 and 40 m^.n. were detd. "formaterials of grain size ASTM No. -5 and 9, reap* propagation rates .were ¿early independent of grain size. • . ' .

125¿ Griéss, J Cf Creak, G E - •

DESIGN CONSIDERATIONS OF REACTOR CONTAIliMENT SPRAY SYS.TÍMS. Part X.

. ' The stress corrosion cracking of types 304 and 316 au-steni.tic stainless-'.-'- steely are discussed. _.'

pRNL-TÍí-2412 (Pt.ío) 22p. : 1971. _ . - . .

126. Gromova^ 'A % et al ' . '-..'..

EFFICIENCY OF VARIOUS'METHODS OF PROTECTING 1KE18N10T CHROMIUM-NICKEL"-. STEEL FROM CORROSION CRACKING, AT HIGH TEMPERATURES, ( i n Russ ian) '

• F iz iké -Khim. -Meklian. Mat. 6 : 4 , 4 4 - 7 ; 1970. ''" „ . ,

• - " - ' - , - - ' . ' " . • -' - 4 5 — • " ' • • ' . - - ' - - '

¡V

127.Harston, :J Dj Scully, J G . .

FRACTURE >ATH OP STRESS CORROSIÓN. CRACKS IN AUSTENITIC STAINLESSSTEELS. ' ' • " • ; • *

Nature 221:5183, 853-854? 1969* • .

Stress, corrosion cracking in austenitic stainless steels having a'. nominal composition of either 18:10 or* 18 $18,. some with, additions...of Oα or Co austenite stabilizers, was studied» Specimens were-'stressed.as a IT bend and exposed. tó concentrated MgClg solutionboiling at 154°C. . Scanning electron microscopy shows that cracksfollow.-a crystallographic path, an observation not.made before.Such regions, were always well below the original surface of the .specimens. The crystallographic aspect of stress-corroded:surfaceswas apparent in both 18:18 and 18:10 alloys, but considerablymodified in the latter alloy and apparently absent in 18^ Cr-iO$ Ni-Zfo Cu alloys. 7 references. .

128,Harston, J Dj Scully, J C '

STRESS CORROSION OP BYEE 304 STEEL III EpS0./NaCl EN7IH0BMEMTS ATROOM TEMPERATURE. • • . . > .

Corrosión, 25:12, 493-5015 1969. . - . , • .

The stress corrosion cracking of 304 stainless steel in SNHpSO^ +0.5.ÍT NaCl at room temp, has been studied by scanning electronmicroscopy. Specimens in the form of thin sheet with, two grain sizeswere subjected to simple TJ-bend tests. Cracking was initiated mainlyas a conscience/of grain-boundary corrosion but cracking was mainlytransgranular below the outer layer of grains. Crack propagationoccurred as a result of the formation of parallel tunnels acrossa graia. . The width of tunmrfcs was greater in the larger grain sizematerial. ..The subsequent, formation of the crack surface occurred partlyas a result of lateral dissolution. Crack'propagation occurred across(i,li) piane,s in the large grain material, quenched from i3003C. ,' '.'!Cracking results from the dnteractlon of dislocation pileups , : •with the environment as;, a. result of which transgranular disbjutiónoccurs more rapidly than grainboundary corrosion. The relative rates /of corrosion of these metallographic features are a function of alloy •constitution and environment composition. 14 references. '•

m

fi;-- 46 -

• •

129;.Hawkes,.- .HP eial • . •.

.EFFECT OP APPLIED STRESS. AND. COLD WORK ON STRESS CORROSION CRACKING;OP AÜSTENÍTIC STAINLESS STEEL BY BOILING 42 PERCENT" MAGNESIUM CHLORIDE,

Corrosion 19:7, 247t-253t? 1963. , , . „

The effect of applied stress on the stress-corrosion crack morphologyresulting1 from.the exposure of Types -304, 309, and 316 austeniticstainless steel wire specimens to "boiling 42$ by wt. ISgClp wasstudied. Crack morphology depended on applied stress; the depthof crack penetration iras inversely related to the applied stress,while the cracks per unit length of specimen increased wátía appli,while the cracks per unit length of specimen increased wáftía appliedstrength.. The area of greatest attack and failure was in thematerial exposed to the vapor phase of the environment, slightlyahoye the liquid-vapor interfaced Differences in resistance ofTypes 304, 309, and 316 to stress-corrosion cracking were minor,with Type 316 the most resistant the. Type 304 the least. Introductionof air into the boiling soln» reduced deleteriousj the most severecondition occurs at approx. 10j£ cold work. The nature of stress .corrosion cracking resulted in a rather wide dispersion of time-to-failure vs. stress data points. This dispersion increased generallywith decreasing stress level or length.of test* .

"Serbslebm G; Schwenk,. ¥. ' . . .• •" ' " •• *

CRITICAL LIMIT STRESSES FOR PRODUCING STRESS "CORROSION CRACKING OPMATERIAL ( CHROMIUM-NICKEL) 4301 IN BOILING KAGSE¿IUK CHLORIDESOLUTION (In German) ...-."-.-. ' . " •

Werkstoffe u. Korrosion, 21:1, 1-3; 1970.

An attempt was made to determine the critical potential for thedevelopment of stress> corrosion cracking in a tensile test bar of anausténitic Cr-Ni;st^el in boiling 42$ MgClg solution, TIae results •-;-show that there is á-critical potential ant a critical tensilestrength which.ase intereependentj. both must be exceeded for theoccurrence of: stress corrosion cracking. The results were in accordwith earlier work, ' " • ^ - ,

47

•.•''..

Herbslev, Gf Ternes, H . • " i ' ' - .

KINETICS OF STRESS CORROSION CRACKING <?F AUSTENITIC CHROMIUM-NICKEL.STEELS'I NMAGSES.IÍJMCHLORIDE; SOLUTIONS]), ('In German)- •' . : -

Werkstoffe u . Korrosion, 20 :5 , 379-88; Ip69 . " •,

Tests were ca r r i ed out on the s t r e s s corrosion cracking of X5CrNii8 9 rX5CrNiMbl8 1C, X5CrNiMol7 13, XlQCrNiHblis 9,. and X10CrMMoJJbl8 10 s t e e l s

',in. 42$ MgClg-solution a t 144 and 130°C. !-Tlie cracking r a t e q / ^ thep o t e n t i a l a t the base o f t h e crack, which depende on the surfacep o t e n t i a l l i m i t towards more noble valueá. below which no s t r e s scorrosion, cracking occurs . The influence1, of temp, i s r e s t r i c t e d to ~the crack propagation per iod, and does arid a f f ec t the incubat iontime-(which i s s h o r t , and accounts for o J 10$ of- the specimen l i f e ) .

- Increasing Ni contents may influence the ef fec t -of Mo add i t i ons .19 re fe rences . - '•• ' . . - -• • \' ' .'

• Hildebrand, J F • ..1 3 2 . ' ' ' ,=• - - '.•"

. " E7ALÜATI0ÍJ OF STRESS CORROSIÓN RESISTANCE OF AISI 4 3 4 0 AND Í74ÍH'.'STAIITLESS cSTEEL M A T E R I A L . .....'.: :. ' " ]'\ • '. ' '

• ., • • i1. • '• • .

N63-21648, lOp. 1963* • ' 'j; . . .

Tlie heat treatment of the stainless steel -speciments to the .200-20 x.103 lb./m.2 strength ievel is described. . Th$ stress-corrosion ": ,'-.tests were run at increasing stress, levels, '¿Starting, at theproportional limit stress as détd. for each Raterial by a' stress- • .strain curve. Neither the AISI'4340 nor the |i7-4pE bar stock showedany susceptibility to stress corrosion at 200-20 x 103Ib./in.2

H i l l , B ; T r u e b , L F . ' . ".- ' ' | :: *•••-.'- l. '.1 3 3 . • • • ° ' " • ' - • . - • ' , • . • • . . . - i! '

• RESISTANCE OF EXPLOSIOiT-BONDED STAINLESS STEELf. CLASS'TO IHTERGRAMLARI CORROSION AMD-STRESS CORROSION CRACKING.. |-

• : : : . . i ' ' -- : v - 4 - •'•'•.''."'

Corrosion, 25:1 , 23-29; ^969, - '--:. !- • • " - • f l 1 : ' . ' : - ' • " - - \ • • - " ' ' . - ' " '

Intergranular bqrrosion <5f s tabi l ized au'stenitici ¿stainless '3teel• i s not accelerated when th is material i s explosilonelad to C s t e e l .

' ,Heat treatment sirr tlie sens i t iza t ion range causea, C diffusion across, ;". . tire bond interface and prec ip i ta t ion of chromium| carbides; ' th is ;

influences ' the .corrosion ]rates within the diffusion.band» Outsideof t h i s --"relatively Rainal Icáreas,'-.corrosión rates. |aré similar to -thóse= 'character is t ics ' -of hohclad "material subjected to ¡the same heat ..treatment. /Stress^ corrosion cracking: of-both a'sijfeabllized-and "an uns'tabilized grade of> a'^istenitic s ta in less steely i s not/ acceleratedby explosion cladding to C s tee l . S t a i n l e s s ...S-te'el^to-ste^l explosion "clads thus do not appear to pose any Special corr¿|sion problems.

' í 17L references. '"- = «*)!48 °

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: cracking was' fo: specieens for e:. are copparable •

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' contaminated sodium .(>« 30. pplí oxygeH9r!waá;?|tudítéá a%ví,2i3p "and í400eF¿ , •'..''' y A gray * surface; scal;e, identified ás sódium chromite,' formed.i.at ^ '

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; a Surface layer but 'peáétíAiíéaiál-Óng-gí^fo^lrtiAndtí'ésîííto the base' ¡ metal* .At 140Ó°F a gveéa, thin ¡surface layer f onigd. wliicl . ,iras •;

', "•, ;• '¿^thpúght^jto.ibe made/':upj-..ofi';~twoV"components¿'-''V iiés'eftótfiSalJ 'ene tíRatioji.',; ;; ;.''•• ;'tfcQúrké^than/,w,oji%v<»puic.at;¿aá"-£iuiválgñfc-'tiWfand.' oxygenr lev.el á t•

'';' ; ;DÉtELOHIEÍiT OF .STRESS (30RR0SI0N CRACKS IN AÍfSTMÍTIC C»-Ni STEELS.

Sbi»1 I , Nb.l;,l,2,í

i i fect^loaded, axially- gtyés'Séd'' .8p>ciJnéhs of a ^¿piely' of austehit ibM l ^Cr-Ni steels were exposed to boiling' 42$>, JfeClg s.oln. f, ,TJh.er progress of

cracking was'followed by potential measuréiíen€s'Jaiíd^^ removing

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^ mb;s£'^po£t^^ .•;:'s'tre'8S j ; ' jsúid:,"sQ";;iras.. not-.lréôîizé'd: py^xou'slyy^'The êracksi,',' "opejt.:"upand. ibéc orne br&iche d during, the 2nd: !sta|e,, which i i s ' a6companie d by ""•.'a f a l l 4n"potential.ií ;Thé relat ive duration of the induction periodtheôâlífperiód of «crack propiagation varies considerably. wi,th ^ β ,

lexpjl. conditions, v part icularly the "size >aad;°f ó rm; of thfi ^speoíáen >an'd 4B%7Í|^;i^£?^rsXá^Li(gâ:'büt"' for íul ly softened, axiill^Lyi"ttr#se.eJ,

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'->f-P'P- 8ésÉ'}Íf$ÍVÉ$ :'6% " l i tpVs GOMPOSIOir ON THE STRESS CRÓSSIÓií BEHAVIOUR OÍ1

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' H ó a r , T P1 3 7 . '

,, ffl&fo jjîífiúJ^Q Metallic.'

. -( /Pleírar^'^ cx 'dcliig-facts* aad fi¿iíé (^r•/Jj^'r¿Y^rf.ett^írl ^ -' -nV'Áftkí'Viir ñr*/itVaiPftí*fciftn p e o ' u i w ñ , 'Auriga*!! i t v ^ h o t l"bi?'í**'b'<Él<r^^^^dj?;\;w^^jü^5trb¿agátiQn,req;iiires;á4icPt¿lítyV not Mi^í^tleness,

l -^Stf^h^tóéíál under attack.; Por rapid stres3 corrosion cracking thesupply' of corrosive reigent from the environment ia a critical

' faotpr.:f Stress corrosion cracking can only occur when the. metal hasvery special properties1 and the soln. a very special cbmpn. ' ' ,-.••..8 4 r e f e r e n c e s » ' ' ' •• .-••- ' '" . . • . - • . -' - ' - - - .-•

< . . . H o c h m a m i , J ; B o u r e a t ^ J > " * : - - > ; ^ ¿ i - l - ' U S , : . - c ; : >• ! -'••-• •'•• - • ' • •S 8 , ; ° ; • • ; - . : , - ; . , ; • • ; • • • ' • • ; . ' / - • • • . - ; - . • . . . . ; • - . , • • . : , ; s W

- S T R E S S C O R R O S I O R ' Q R A . C K I l í G . O I I - . i e / í O W í S T A I i í i E S S S0?BEL'. : : ' '••',''.•'"•'.,

• , •• " i * *{ -~\

íy¿ / ^ J / J , p ; C ; C r - M " . - H i tWeíe raádé -with .0-4.l?í Si .\The^LVére4^ and/airícoolfag Jand l(b) .-VÍth'^.0?f::P'old' jtoric^ aí'te-r ..(^)'Í!3ie .ffiinple-: surfaces were 'p'olishek' .mech."atfd:súi3Í|^cired':^ with!'.3^3$" Si ;

"íásíted-1000" hfsX, when."the iiésti-wasi-stopped.- Kie 'sampíes with ;only0; 0ÍS ;1Si,' lasted" ^nlys ÍL5,3-3ÓS> hr;s.- a i t é r •'testing treatment• (a) * and

iÓF:^S^ÍTlé;S!riíJniESS'"ST]®5SV.;; Îh'lêií^1)1 ' ' , .

^ó'áÂntiôraroaioniiAi^jyíSgg^.^ '' •'-", ' ' ' "'" '''"'"-, ' , • .' . ;"

After a, review of the basic phe home ¿A arid the • thieory of stress corrosión»-,of austénit íc s tainless steels,¡ prevkntífe measurjes/to be taken are ¿,.

discussed. Surface"prepn. C^;..changes i n óhem. analysis pf the s t ee l ,are moat STieceesful in pWve, |íí,ng s-feitess corrosion* The investigationcomprised part icular ly, the influence-ys Si knd Si addns. and theinfluence of .the eueteñitic-fejpritic ¿truotúre. \, ->.. ? .

^ . . •

~ i - " • , ; . •

140. Ito, G

.' ^STRESS- CORROSION CRACKING OF AU'STENITIC STAINLESS STEELS, (in Japanese)

KagakuTo Kbgyo (Tokyo) Í8*:2'¿ 264-71j 19S5. , '.'•'[•'•'

... .''.. A -review-with-13 references. '" • ,

Í41, ito, S

STRESS CORROSIOlí CRACKING OF AÜSTENITIC STAINLESS STEILS. I. AUSTENITICSTAINLESS STEELS, (in Japanese)

íT£ppán Kinzoku Gakai Kaiho,,.8:10, 708-16j 1969.

\, Tlie effect bf elements, such as Ni,Cri,Mo,'Si,CufN and C contained inaustehitic stainless steels on ibhe stress corrosion cracking (sec)of the steels, formation and growing of sec, and mechanism of theanticracking effect of alloy elements, are reviewed. 50 references.

1 4 2 . " . l t d , ' G • • ; - ; . ' • :'

• STRESS CORROSIOIT CRACEIliC- OF AUSTMIflC STAINLESS STEELS. III.' "STAINLESS STEELS IN HIGH TEJiPlEATURE 7/ATIH. (in Japanes'e)

. Nippon Kinzoku Gakkai Kaifo 8:10, 72Í-7; 1969,

The effect of 01 ion concn., dissolved 0, pH, temp., and stress onthe corrosion cracking of stainless steels in water, the effectof steel compn. on the stress corrosion «racking susceptibility of

. syistenitie stainless steels, cracking of 'ferrite stainless steels,,,:. particle segregation in Nr" alloys, and anticracking treatment of

steels dn hi¿ia temp.i water, are reviewed. 64 references.

1 4 3 . I t o , S e t a l ; ' .

'. .. :?• : COBROSION OF AUSTENITIC STAIJILESS 3ÍEEÍÍ'IN HIGH-TEMPERATURE^ FLOWING, ¡. ¥ATER. ( in Japanese) ;- '."•'','•',"'. '•. • ' .'. '••

Bosiibku Gijutsu Í7:Iji3/l'lj; 440-8$ 1968;; í - •" '" , . -

, Siudiés -were conducted on SUS '27", a type* 304 austeni t ic s ta inless'-..'•• s t e e l , a t 320* ^ d at .flow ra tes «up to 18 i . / s e c . The corrosion.

pro^lupt filri formed oil the suifface of the s teel under; the^e: conditions was composed of magnetite only in contrast to the

coexistence of magnetite and hematite formed in s t a t i c t e s t s .

- 51 - Contd...

146The effects of purity, amt. of disolved 0,: and the. flow,rate of HoO

" on- tii'elcorrosion rate of stainless steel >were related to one anotner»The corrosion was severest when the pond, of .the test.'-HgO. was

'***6 x 10-4 mho/cm, and the amt. of dissolved 0 was ¿.0.3 ppm« Intest HpO'S of .higlier 0 content, A J 2 - 3 ppm., the corrosion waa milder.The corrosion rate was reduced to the lowest value when the purityof HgO was kept high. The effect of flow rate of Hg0 on thecorrosion rate was noticed only in low purity H O

•144i•

EFPECTS OF ADDITIONAL ELEMENTS Olí THE SUSCEPTIBILITY ¡OF AUSTENITIGSTAINLESS STEELS TO STRESS CORROSION CRACKING IN HIGH-TEMPERATURE WATERCONTAINING CHLORIDE;. . ' . • - ;..'-••.. .:•

Trans. ITat.-Res. Iris t . líe ta l a.'(Japan), 11:3, 1=76-82; 1969.. ^

The ability of the alloying elements !T,Ni,Si,T,Mo,Re, and Al toreduce the susceptibility of vacuum-melted austenitic stainless steelsto stress corrosion cracking in high-temp, water contg. 60Q-ppm ofchloride ion was investigated. The majority of alloys examinedexhibited a reduced tendency to cracking .compared with commericial304¿ 304L, 316, and 547'steels. The, 18:8'-"Cr-Jii alloys'contg,;¿.QtOZ'/o É were, however, highly susceptible to cracking. Increasingthe amount of STi-in the 18^ Or alloys from 8 to 20$ .decreased thetendency to cracking» •'"'..

147,

148.

1 4 5 . l i b , G e t " a l • . . . . .• , ,; "-,. .. .:,--;-., ..••

'- EPFECTÓ OF IMPURITIES OK THE 3ÜSCEPTÍBILIT.Y O?'AU¿TEfíITIG STAIULES.SSTEELS TO STRESS. CORROSIÓN CRACKIMJ III.HIGH TEMPERATURE WATERCONTAINING' CHLORIDE. (in 'Japanese) : ; . . "••

J. Japan Inst. Metals, 34:1, 101-107? 1970, •,. , , , . .

The effects, of C, Si, Mh,. and P on the resistance to stress corrosioncracking of.austénitic stainless steels were studied in pressurized,high temp, water contg. chloride. ''The tests were carried out at300°C for 300 h in an autoclave, cdntg. absolution with .600 ppm CI"prepared from NaGl/and pure waters The same alloys were also [tested in boiling ^gOl^ solution. Alloys contg. P ^ ,0.03, C ^ 0.1,

1 Si >• 2 or lfti' »i'.5<w:t. were higlaly susceptible/to cracking in 'aqueous solutions of liaCl or «5T2* 9 references.

- 52 -

146» Iliescu, E et al

;. STRESS CORROSION CRACKING OF*Cr-lfei-Ni STAINLESS STEELS, (in Bussian)

Metalurgia, 20:1, 8-11; Jan. 1968.'

Three austenitic-ferri.tic and 'two austenitic steels, similar to 18-8grades but with low Ni contents (3.60-6.28$ Ni) were studied underconstant stress in ah indirect-stress tester, in a 42$ solution ofbjdilirig magnéáium chloride. • At a streas of 30 kgf/mm2, all specimensruptured^in less than 1 hr, exhibiting transgranular and intergranularcorrosion. A Fb-stabilized 3teel (0.53$ Nb, 4.85$ Ni) withstood astress' of 20 kgf/mm^ longer th an any of the others (175 hr), showinga preppnderaneé of tranegranular» corrosion over intergranular underthe microscope. At 10 kgf/mm^, the life of the specimens rangedfrom 155-590 hr. The steel containing the least Ni (3.60$, austenitio-ferritic structure) failed at 590 hr, but without^cracking andshowing no signs of corrosion. .7 references.

147. Jackson, R P

STEESS-COHROSION CMCKI1ÍG OF 17-4 PH STAINIESS STEEL. •

DP-779 (1962)

148. James, L e t a l .

SPRAY BOND TEST EVALUATES STRESS CORROSION CRACKING BEEfiJIOR OF• AUSTENITIC'.STAIBLESS STEEL AND OTHER MATERIALS.

Mater protect. 2:11, 18-22, 24, 26? 1963.

• Stress corrosion cracking behavior of awstemtic stainless steel and- other materials wetted by ehlctide-pontg. potable water wasinvestigated. Details are given of the-spray bend test" procedureand app. Wrapping Al wire around pipe surfaces prevented crackingwith certain 1imitations, c,steel was equally effective.1 Severalmaterials, "including com...grade Ti, were resistant to cracking in thetest environment. . Results are tabulated. v.v • • ;

- 53 -

J

149. Kalichak, I B etal . - . ^ ._...-- , :,

FATIGUE AND CORROSION-FATIGUE SIBEIMH .OF SfOME. MARTENSITIC STAINLESS,,. STEELS, CONTAINING...12$ CHROMIUM, (in Eassian)'

Fiz.-Khim. Mekh. Mater., 6:3» ?ii3-16;' 197O.: '•'

.The effect; of thermal trea-tkeht, alloying degree, and rerefining-. . . .treatment 'of :,%2$''Gx steels •ÍKhi2N2VMFj IKht2N2M7FBA, an3.,2Khl3

-;f, on :th,eiTy durability -In várious-média Vas studied.^ All steels were, .' .. .Vmeite'd'.in. elecl. furnaces,1 while-steel ;ÍKhl2N2M7FBÁ was/addní»

." .¿melted "by .the.eleetroslag method* ¡Corrosion-fatigue cracks had\ ; transcrySt.' character. An atni. cf moist air^lottered* the 'ultimate

. fatigue Strength by 15-25^ as!"compared" to the -same .strength in. ... normal -lab..- a i r . .The1 ultimate fatigué strength of these, steels

., , increased, jnonotofiically together' with increasing'.tensile strength; , withiniftjie'ranges 95-155 dair/mm^ while, at -the same time ultimate

corros^ri-.fatigué; did not change. The refining during electroslagmeltirag increased, the' durability' of sieel lKlil2Ií2M7PBA i ^

18!

150. Kamaclii, £ etal : ' '. ...

MECHANICAL BEHA7I0B-.3F AUSTENITIÓ STAINLESS STEELS Ó THE'PROCESSOF STRESS CORROSION TESTING, (in Japanese) . ... .: "

Mppon Einzoku Gakkaishi-35:1, 64-70j 1971.

For the purpose of investigating the stress corrosion process interns of material strength, several specimens subjected to stresscorrosion "testing.were éxaind.- by using x- ray 'diffraction methods,,the dislocation ,ds.i were measured by transmission electron microscopy.Hate specimens for tension tests were prépd.. from 0.3 mm.thick . •material of STJS 27 and. were :éíeetrblytically polished.. Tliese :specimens were tested by a tension type .stress corrosion ..testingdevice '.ai &• 42$, MgCl2

;'saln. at 154° under stresses; 13 .30 kg/sun^.At several stages:- in.- the: testing process,' the'•specimens were^'takenfrom :the app.:. and the x-ráy diffraction páttérne- were measured.Tlieae .specimens were, then thinned electrdlyticai.iy and, .ttieir - .dislocations were obsd. Many of the disíócatibns.piled up at.grainboundaries, 6r had-unform distributiohs; in grains' including: stackingfault formation. The dislocation d. reacKes'thfe value of 10"/cm2 '.or over, when corrosion cracking takes place. The x-ray data- ofhalf-width ratio b/B vs. corrosion time T curves are analogous withthe dislocation d» curves, and the results of lines profile anal, .showthe effect of strain broadening.

- 54 -

151* Kawahata, M et al

, : STAINLESS STEELS RESISTANT.TO STRESS CORROSIOlTCRACKIilG.

U.S. 3,438,769 5p. 1969. (Patent)

According to the experience of the authors with such craoking ofconventional stainless steels contg. ¿-0*9% Si and <»-i9.5?£ Cr +Mo,these failures could not/be prevented with ¿-&0/o Ni, which, was toocostly. Investigations of: compns. cohtg. i6-20J£ Ni showed thatsatisfactory resistance to such cracking could .be obtained in themwith higher Si, and lower Cr and Mo. Test results are reported on

: specimens of various compnsi.stressed in tension at 25 and .,'35 kg./mm.** resp, in an aq. soln. of MgCl2 boiling at 150*, to showthe effects of compn. changes on the time for failure by cracking,

1 • i

182. Kawamura, T; Oka, H

STRESS CORROSION CRACKING IN STAINLESS STEEL EQUIPMENT AND ITSPREVENTION, (in Japanese) .-••-• " t '

Sekiyu to Sekiyu Kagaku 11:6, 19-27; 1967.

A review is. given on stress corrosion cracking in chem. industries.14 references. •'-:>'

153.. Kazuo, H et al . ,; •• ,

' ATMOSPHERIC,STRESS .COHROSIOIi CRACKING OP LOW ALLOY HIGH STRENGTHSTEELS AND"STAINLESS STEELS, (in Japanese) " ' • .

Zairyq: 17:179, 720-8; 1968.-. '' : • ' . . ' . . •„

Expts. were conducted extending over 3 yrs. in which low-alloy.., high-strsngth steels and stainless" steels were exposed under .s.tatic

• load to various types, of .ajbm. i.e. industrial, marine, and in, .rural. No cracking.either in the welded or in the nonwelded ,.specimens of low-alloy.higli• strength steeísValso did not.show anycracking. Pitting and intergranular corrosion occurred, however,in the heat-affected zone of the welded stainless steels (SUS 50

Cr) and SUS 24 (l8# Cr)).

<- 55. -

a., K ," '

•VC-í'

* • !

154. Kenneth, E!. r • "• •• " : ' '; '

METHOD OF PEOTEC.TÍNG-.AUSTENIGÍItííSíAIlffiESS-SfEEL SUBJECT-TO" STRESSC O R R O S I Ó N . - v "'"'' ' * •:''•''•"-•- . . . ,r

U.S. 3,378,359 1967 (Patent)

\T^'^é8íet'eMQe'-of'-mat&oiiii.Q,.f.ia.ÍalBsa s tee l ' contg . S^'M and 18$ CΓ'to s t res s cbri;osi.on.crQ.okiñg;an.'chloride -and0.sulfide atm.'. i s '

r improved by.' partiality coating the:, surface' with Á1" and' lieat-tre'ating a t/aÉ-lSÜO j1. for i"h'r". . In: corrosionttests",- i !partially ; Alcpátéd s ta in lessBteét:;¿o¿séshoes re fluxed., in ' 35.0 .'gy MgCl¿«6Hgb-aHd 40 ml. *HgO at&oy&i failed in.,*^v>38 days :as 'compared •Vα Iirs. for unprotected •specimens.. ' Vr;,..

. • > ' • : •

155. Kirkpatrick, H B et a l . ' . . ,. Í •

STHESS CORROSIOir. / . . , ; . '

Mach\-Design, ^40517, 188-194;" 1968. • . - - • - i ' • ' ' "" ": '

•Stress corrosion cracking haa.ibeen'- ident i f ied as the cause of - fa i lureof, low,carbon s t ee l in r iveted boi le rs and pressure vesse ls i ncontact with hot a lka l i solutions.- of brasses and other Cu al loys i n

- ' <environments containing ammonia, o f •s tee l landing gear s t r u t s andAl a l loys f i t t i n g s and of high strength s t e e l s and Tl al loys underhigh electrochemical p o t e n t i a l s . Metals affected show sharply-reducedt ens i le strength, reduced duc t i l i ty and,very l i t t l e elongation tofracture . Time to fai lure depends on s t ress level andcra.cks tendto be narrow and extend deep into th'e'ímétál. A table lists,, ;".'"

•r.erivi-róna'ents known ijó cause s t ress corrosion of Al, Úif eusteni t ic andf e r r i t i c s t a in less , carbón and low steel/-high, strength alloy s t e e l ,ISg"",- NI and Tl. Design precautions include measures such as i imi t ingtens i le s t resses , eliminating residual tensi le s t resses , eliminatingcorrpdants, in fhe- .service -environment using--'cathodic protfectióíi ando'rganic- opa t ings '¿, ' Several- factors: are consid'ered ás i'éspcm'óibie for

• '• s t r e s s ;¿orr'ósi'on iricludi ng an., anodic sh i f t , the presence '•'. of"''; :• .el^ctrqchemicaliy.'.suscep.tible paths, s train-accelératéd stránsformationperiodic éíectrocliemical;^ mechánieál• action^ layer-rupture a2;oágweakened' 'regions and H9,.. reaction,-/ ll-^eferfences. '-•> > • ' : ' : ' • '

- 56 -

156.

157. . I

I' C

158. E

1

I

Ada

w.r

• - ;tt ;"'.-"-;a

. -: 6:b.

ing atilesa

Llure

in

luced

nd .

Lc andsel,..-;ingtingmdfor

156, Kishima,. 8 .

'EFFECT OF' TEMPERATURE ON THE SUSCEPTIBILITY TO STRESS CORROSIONCRACKING OF STAINLESS STEELS, (in Japanese)

; Boshoku Gijutsu 17í9, "381-8; 1968.' ,

'..''. Arrhenius plots, were made using data on uniaxially stressed specimens..'/\,of types 304, 303Se,\ 201 and 431 stainless steels immersed in 35$-

; JigCig.soln, at various temps.', pE of Miich had been adjusted to 3at .22° by, adding ,HG1¿: The reciprocal of time to failure, was taken

. : as the. rate of stress; corrosion cracking. Tlie results were in good

agreement with the Arrhenius1 equation. Both-the activation energyand logarithm of. the rate coeff., i.e. the preexponential term,, increased, in direct: proportion to the stress level applied, and thelines Illustrating tíié above relations broke at a stress-levelcorresponding to 0.03$ proof yield strength of types 304 and 303Se

. steels. As for"the other steels such a break was not evidentlyobserved. It is concluded that the rate of stress corrosion crackingincreases with applied stress.

•\ - " ,'-•' •... - J

157...Kishima, S

EFFECT OF TIÉÍÉERATURE 01T TEE SUSCEPTIBILITY TO STRESS CORROSION•''CRACKIJSG OF 8TAIIÍLESS STEELS. '• .

BNWL-TR-53 21p. 1968.

158. . Kishima, S

' THE MECHANISM OF STRESS CORROSION

Eroc, Inst. Conf. Fracture 1st sendai, 3, 2025-51; 1965.

Á brief summary on the present situation of a research programdirected; towards, obtaining^ a better understanding of the mechanism ofStress, corrosion umbfittlejaent -of'cracking in;2 systems, stainless

/'S^téeí/^Glb and bfáés/amcibniacai soln., in presented and «discussed,.; which eomparises :the following .aspects of the, problem; i) cathbdic; reactánt;i;n:Mg01¿'"solii.,j (2) appareni;, ac^va-feion-erergy; (3) delayed

- .-:' time to, fracture;' (4)"::delayed^frácture ;curye.j»(5). effect of'solute^f '-:átbás.jr-:f'6.).Jpr(6teptiyé ciá.j (7) effect óf cold work? (8) chloride- -.••: cracking" óf "marten^itic s.t¿xiíleoas steel; and, (9) ammpnia-c racking of

' .,' ;'/brass.".'k45;; r e f e r e n c e s 1 . _•/.'-" ']';-•„'/. i -,'.-;-•.' 'v.'•-'...; .-;,•" : ••.:--••.•.•.••. •-." /-•', 1;-- v..

- 57 *.

159 . Ki tamura , Yj I t o r i t a , S

CATHODIC PROTECTION FOR THE STRESS CORROSION CRACKIIfG OPÁÚSTENÍTIÜ.STAINLESS ..STEELS. . , • , - • . ' . . - . . . . - . .

' B o s l l o I n i v ' Í 3 i á u Í £ f u ' " i 2 > , ' . 3 2 4 r 7 } / l 9 6 3 , ' \.-\-: '••• v ; ' ' v - - ; ; ' - ' '•• --•'••)•••••' -

Stress corrosion tests were made by using austenitio stainless steelssuch as SUS 27, 28, end 33. The test specimens used for the const.••strain mfcthbd ,and the const ¿-stress method w.ere : coated-with- f lame-.'-s^íái^dAl (9,9.9á$ Al.,- 0.1-0.2 nm. tliiok). or Zn-rich-páint (crintg.J* 9,5fo,,Za,. p. 1-0.2-mni.' 'thick),.and tested in 42$^ MgQlg spin, .at 154°.síjx'facertréaíed specimens were- harder, to» crack then untreated ones.

Zn.. 'showed, alinost the-samé-value as that', oí Al or Zn.alone.;i

•160.-..:Kohl, . H'r.: ^ ': ' ' '' ' . : \-:'•„;;•"";...•-.:; ":-

STRESS-CORROSION CRACKING IN AUSTMlTIC STAINLESS'STEELS.-

Eadex Rundschau, 4, 606-619; 1965. :. •.•;.,• ;•'•'.

Test methods and results are described. The dependence-of--service, life, bh tempi and concn. of the test soln., the,-influence of, ginding,polishing, and shot peening of the surface, and of the alloyingelements C, Si, N, Ñi, and Cu in Cr-Ni and .Mn-Cr-l-Ti steels arediscussed. r . - ' » ; ; •

162<

163<

161. Kohut,'- & B.' et al • ..

' ' SULFIDE STRESS- CRACKING CAUSES' 'FAILURE OF COMPRESSOR 'COMPONENTS• RBFimORY SERVICE.. ',- / • . . , . . . ' .' •:. • / ' ,• - / - . ; . - • : - i

I f e t e r . P r p t . 7 : 6 , 1 7 - 2 2 ; 1 9 6 8 r '• ' / ,. . . . , . . .- . . . / . , , - . : , .

Failures'; of'.centrifugal comprgsspr compoiie^ts liave occurred in• refinery environments contg. HgS.• Wat,' acidic'refinery streamsrCpntg.^HgS cm-Qause', cracking' or -•suscepiitie' materials, but .wetstr.eaáa .of HgS contg ."quantities of M g resulting "in alk,...cohditiQjasv'dp not'. ;?Lpw alloy° constructionat steels Wid pptii.j. 'hardening stai.nless Vste^ls"• witli yvieId strengths ".above °10Q,000 psiy

are highly, susceptible to cracking. Steels'properly heat .'-treatedto. 90.,000cpsi max* are «not"¿useeptable, íT± base. pptn. hardeningalloys, Mbnél K-50Ó W/'Inconel X-750, are .not suscept-ible tocracking» : Fabrrcationjprocedur.es and heat treating, practices forimpellers operating in streams capable of causing sulfide stresscracking should be controlled to, minimize plastic, defornsation,residual stresses, and. damaging structures, particularly in welds.

5NÍTIC

steelssonst,-.ame-íntg.154°.ones,rere

Al or

162. Kowaka, M; Fujikawa, H

. .'EFFECTS Oí1 PHOSPHORUS' AND NITROGM ON STRESS CORROSION CRACKING OFAUS.TENITIC STAINL'ESS STEELS IN BOILING MgClg SOLUTION, (in Japanese)

J. Japan Inst. Metals, 34:10, 1047-54; 1970. . , . ,

The influence of P and N on the stress corrosion cracking, of 18:10 Cr-Niaustenitic stainles3 steel in boiling MgCl2 at 154°C was investigatedby the U-bend and tensile methods. The results showed the determintaleffects of P and N, and the interaction between these elements, on thesensitivity to stress corrosion cracking. The general corrosion ratesand.potential/time relationships of these steels in boiling % C 1 ? at154°C were also studied. The results are discussed in relation tothe dislocation structures of the materials. 13 references.

163. Kowaka, Mj Fujikawa., H,

. .: THE EFFECTS, OF SEVERAL ELPÍEKTS. ON STRESS CORROS ION • CRACKING OFAÚSÜEENITIC. STAINLESS 'STEELS IN BOILING MgClg SOLUTION, (in Japanese)

vicefinding,

JS IN

,edng

forss

Ids.

J.' Japan Inst.^Metals, -34ílO, 1054-62? 1970.

,.The. effect of several elements pn the stress corrosion cracking of18:10 Qr-Ni-austenitic stainless steel Was studied using boilingMgCig-at .154)"C ' C,Si, áud S ( 0.1..wt..j£) were beneficial while Mo,Cu,and Cr were detrimental. Mα. in amounts, up to wt. fo htid little effect

but in greater amounts became"detérmental. C,S,Mo, and Cu increasedthe, resistance to general corrosion in the same solution. The relationbetween; stress corrosi'on and general corrosion is discussed.12 references.

164, Koziol, J J; Christopher, S S

CORRELATION BETWEEN- SENSITIZATION AND STRESS CORROSION CRACKING OF300 STAINLESS-STEELSi .. • . , • •. - ' :

CEND-325P-264 1966.

The- effect of préo :idri«-.;£uad:vaí?iations in surface conditions .on thesusceptibility;, to 6-bransgranul.ar cracking; of -Types .304, and .347- stainlesssteeii,were..-studied./.i-Tubing with'. annealeji, drawn,' swaged and diffused.Ni surfac-esi-was exposed -'.'to.*;an aq.. environment to evaluate the, difference:in. .behavior,;of/ ons,tab.lized and .stablized types. (304 & 347),, .of stainlessste>ls.,«ndéx.:^ vtest'1 'conditions.;,-. Tubes with' swaged surfaces(l5?£ redni- iíi a're^i'^d surf dees .contg..: diffused Ni layers ehdv/ed •improved resistance',±o.transgranular .cracking when compared with theother, samples .-evaluated,in' this :program. ' • • • • ,

- 59 ¿

I •

¡ i

Á trend toward increased susceptibility to transgranular crackingwhich was observed for proximized" and sensitilized Types 304 stainlesssteels, confirmed the possibility of interaction between grainboundary oxidn^añd transgranular craclcing.

165. lozlol, J J; .Christopher, S S

CORRELATIONS BETWEEN SENSITIZATION AND .S.TRESS CORROSION CRACKING OP• É 300. SERIES STAINLESS STEELS. -(Final Summary Report)'

82p, 1966.

:¡ i

! !1 Ii !i :

166, Kuzyukov, .A N et al

MECHANISM- OF THE CORROSION' CRACKING OF STAINLESS STEEL KH18N10T INWATER CONTAINING CHLORINE IONS, (in Russian}" • '

Kliim. Mekhan. Mat. 4;1, 92-94; 1968.

Examples of the effect of CI ions on the eorrossion of stainlesssteel3 are presented and some new tests on the corrosion cracking,of KhieNlOT Cr-Ni steel in water oontg. various contentrations of CIions are described. The mechanism underlying the development ofcracks in steel sa&ples immersed for prolonged porióds in suchsolutions is discussed. The relative effects pf stress and directchemical interaction are .considered. The propagation of inmaterially affected by the form of the' mibrostructure and the natureof the predominating structural.constituent. • , •

I !

i!

167* Lacombe, P •• • : "..'•'

. METALLURGICAL AND ELECTROCHEMICAL FACTORS OF CORROSION IN STAINLESSSTEELS, (in Spanish) - , • . > • .

Tech, Pract. 18:80, 23-34; .1969. • • .

Tlie. individual effects of the coHstituents of stainless steels on tbaecorrosion resistance are reviewed and criteria for selecting steelsfor specific applications^ are discussed. The metallurgical . .structures of;:Fe-Ni-Cr alloys (e.g., Inconel") and the-function, of the

. more important addn;-elements are examd; Max. resistance tointergrariular attack by'HNOg is obtained when the C content is very

'.. low (0.02-0.04$). Th'<=r:presence of Si, N, and JJh affects the; austeñitic structure, and hence the resistance to acids and salt solns|

Tlie advantages of the Cr~Ni-Mo-Cu austeni'tic-ferritic steels for usein chlorides and caustic solns.'under low stress conditions are point<out. Examples are given óf the electrpchem. belaavior of stainless'steels"iñ cprrosive inedia. The uses of'potential zaeasuremehts and ofthe electron and optical microscope for studying intérgranulár pptn.are described.

, '•• ' • „ , -• • - 6 0 - • • ' - . . •

kingstainless

n

:ING OP

.OT IN

Lessikingis of CIb of5hiirect

B nature

168. Larriok, A P

; " "'"IJEIBITION OP STRESS CORROSION CRACKING. WITH PHOSPHATE SOLUTIONS.

BHWL-763 22p. .1968. . . 1 " . .

Autoolave tests were conducted for an 8-mouth period to compare thecorrosivéness and stress corrosión cracking inhibition qualites ofalternate N Reactor steam generator secondary system water chemistryto that of, the zero solids (hydrazine-morpholine) water treatmentpresently used. Seven tests with phosphate levels of 0-1000 ppm.fsulfite levels, of 0-100 ppm., hydraxine levels of 0-15 ppm., andmorpholine levels of 2 ppm. were conducted. Stress corrosioncracking of 304 s-tainless steel tubing obtained from an N Reactorsteam generator, occurred in both the liquid and vapor phases ofsoliisi. not "containing phosphates, and in the vapor phase over solns.,containing phosphate, but not on samples immersed in the liquidphase any soIn. containing phosphate ion. Stress corrosion crackingdid not occur on lots of unsenaitized 304 stainless steel and304 .stainless ste'el heat-treated similarly to the steam generatortubing not did it occur en Inconel 600, Incoloy 800 or A212 CS¿ wt.losses on the stainless, steel, Inconel, and Incoloy samples werenegligible.., Total, penetration on the carbon steel after 8 monthsranged from 0;02 to 0.3 mils in the various solns.

169» latanision, R M; Staehle, R W

STRESS CORROSION CRACKING OP IRON-NICKEL-CHROMIÜM ALLOYS.

AJNLESS

Is on thesteels

on of the

is very

salt solnsfor useare pointelinless;s and ofLar pptn.

COO-1319-61 . l?5p. .1967.

Prom Conference on Fundamental Aspects of Stress Corosion Cracking,Athens, Ohio.

Stress corrosion cracking-in the Fe-HI-Cr alloy system in atjueousmedia is. reviewed. Special emphasia is given to austenitic alloys.Cracking of these alloys is reviewed critically as a function ofmetallurgical and-ienvironmental variables. ;The various mechanismsof stress oorrosion cracking are considered with respect to theirapplicability to this alloys system.

- 61 -

t.

170. Lee, H Hj ühlig, H E . .

EFFECT OF NICKEL IN Cr-Ni STAINLESS STEELS ON THE CRITICAL;- POTBKTI-ALFOR STRESS CORROSION CRACKING. ,...•.

;J. Electrochem. Soo. 117:1, 18-22? 1970. •

Oreater ants, of alloyed Ni in 20$ CΓ stainless steels iiprove theresistance to stress corrosion cracking in part by shifting the crit.potentials to more noble values below which failures.are not óbsd.

• Tjhen the crit. potential for any'alloy becomes more boble than thecorresponding corrosion potential (Jw 26$ Ni) the alloys are resistantto MgClg.at 130° for>> 200 hr. Nevertheless, rapid failure of such

.^alloys cóntg. up. to 35$ Ni, and probably including 45$ as Well,'can beinduced by anodic polarization to a potential which is noble, to thecorresponding crit. value. Gradual drift of corrosion potentials tomore noble values, eventually exceeding the crit. potentials, is thelikely cause of stress corrosion cracking in¿L.45$Ni stainless

-' steels. Above 45$ Ni, structural factors at the surface or plastically1 deforming alloys become dominant, and failures do jaot occur regardlessof tlie prevailing potential. Pure Ni is anodic to the 20$ Cr-Nistainless steels and can., be used ás a sacrificial anode to protect themcathodieally against stress corrosion cracking. The data support the

«• mechanism of failure .based on stress sorption cracking.

171. Leistikow, S .

INVESTIGATION OF REACTOR MATERIALS AFTER CORROSION IN SUPERHEATED '*STEAM IN,TEST CIRCUITS AND NUCLEAR ' REACTORS, {in Germán)

Werkst. Korros. (Weinhein) 19:11> 938-43; 1968.

In the presence of adhering or partly adhering oxide films the extentand the products of the corrosion of austenitic Cr-M steels and

• Ni-based alloys cari be detd. by planimetric evaluation of metaliLo-graphic crosscuts after 1-200 X magnification. A complete analysis ofcorrosion with oxide losses should include de.tn. of tííe concn. gradientsof the a.lloy elements, e.g., by X-ray fluorescence analysis after

• stepwise electrolytic dissoln.

172. Logan, H L (Ed.)

THE STRESS CORROSION OF METALS.

Wiley. New York 320p. 1966. -:

173,

174.

- 62 -

173. Loginow, A W; Bates, J F

INFLUENCE OF ALLOYING ELEMENTS 02T THE STHES& CORROSION BEHAVIOR OPAUSTENITIC STAINLESS STEEL.

Corrosion 25:1, 15-22; 1969.

The effects of Gg Mh, P,S,§i,Cu,Cr,Ni,Mo,Al, and N on the stresscorrositm resistance of austenitic stainless steels were detd. inboiling Mg-Cl'o soln. P, Si, and Mo affected the stress corrosionresistance of cold-worked material,. C and N the resistance of

' annealed'material, and Ni the resistance of both. Increased amts. ofC,Ni, and Si improved the stress corrosion resistance? increasedamts of Mo, P, and IT decreased the resistance, and Mn, S,Cu,Cr, andAl had little or not effect. This study resulted in a steel coaipn.contg. Cr 18,Ni 18, Si 2, and C 0.06%, with, low P and Mo contents.This steel was melted in an elec. furnace and its properties detd.Test results show that the new steel (USS 18-18-2 stainless steel)is much more resistant to stress corrosion cracking than currently-available austenitic stainless steels. Also,- the resistance of thissteel is better than that of a Cr 20, Ni 34$ alloy that ismarked for resistance to stress corrosion cracking.

174. Loginow, A Wj Phetps, E H

U.S. #,276,864 1966 (Pa mt)

Such steels that can be stressed safely for long periods in chloride-type environments contain, only sufficient C for stable austenitic toinsure, good cold-forming, and low N, preferred compns. beingC 0.075=0.09. Mhyl.4-1.6, P 0.02-0.03, S 0.01-0.02, Si 0.4-0.6, Ni 8-12,Cr 17-18, and N^-0.01$-¿ A steel contg. C 0,075, Mn 1.5, P 0.028,S 0.012, Si 0.5, Ni 8, Cr 17.7, and N 0.006$ quenched from 1950°P.,was stressed to 75$ of its hield strenfth is boiling 42$ MgClg soln.for 4500 hrs. without failure, while other Steels of similar comp.except for slightly higher istt and Cr and 0.029-0.04$ N, failed bystress corrosion cracking in 4-5 hrs. when tested similarly.

175. Louthon, • M R Jr.,

STRESS "CORROSION CRACKING OF AUSTENITIC STAINLESS STEEL. (Sta.tus-Report-Sept. 1, 1964) . .

• D P - 9 5 7 • • ' • ' . . - '

- 63 -

176. Mackawa, T; Kagawa, M

EFFECT OF TEMPERATURE Olí THE STRESS CORROSION CRACKING OF AUSTENITICSTAINLESS STEELS I If HIGEE TEMPERATÜHE SODIUM CHLORIDE SOLU/TIONS.(in Japanese)

BoshQku Gi.jutsu 10:3, 122-5? 1967. _ . ' . \'¡t"

The stress corrosion cracking of anstehitic stainless steels.,.,such asSUS 27,28,32 and 4*3,, in high temp. -NaCl solns'. was carried but "todet. the effects of temp,, , CI coricn. and dissolved 0 contents on thesusceptiMlity. Test temp, of NaC-1 were 100, 150, 200, 250,'.500,325, and 350° and the concns. of CI» were 10,50,100, and 500,ppo.Stainless steels were dipped for 300 hrs.-in"thé NaXl spins.; undera bending stress, of 20 kg./ram.2. in deoxygenated spins» . ( AÓ.01 ppm.),no corrosion cracking was detected in any case. In oxygenated solns.,pronounced cracking on SUS 27,-28j and 43 steels was detected:at;.150-300% but none at 350". The soln.-treated SUS 32 indicated' nocracking in any case. . '

177. Maekawa,.' T et al" , ' .: .' . k.; '

CORROSION OF-STAINLESS STEELS IN HIGH-TEMIERATURE BÓRIQ ACIDSOLUTIONS, (in Japanese) . . ,. , .,...','

Boshoku Gijustsu 17:5, 114-19$ 1968. _ .•

Tlie corrosion behavior of austenitic stainless steels in high temp.boric acid soln. was studied. The general corrosion rate forlOjOOO hrs. was 2 mg,/dm.-2month at 300°. The stress corrosioncracking in NaCl soln. was diminished by the. addn. of boric acid.The general corrosion rate and the stress corrosion cracking weresuppressed by the addn. of 'a small amt. of KOH.

181

1 7 8 . Iffiamcdov, E M e t a l

EFFECT OF-HIGH-TMIPERATURE THERMOMECHAiilQAL TREATMENT-ON THE;-,'STRUCTURE,. CORROSION,. AND. MECHANICAL PROEBRTIES OF STAlliLESS., STEEL, l K h 8 1 N 3 T .

( i n Russ i an ) • " . . . . . - , ; : - ,

Soobshch. Akady 'Nauk 'Gruz . 'SSR 5 5 : 3 , , 641-4$. 196.9.. .. *., _,!/. ,'.'..-..- '

In a lKh21N3T grade s ta in less s tee l (c 0 . 1 , Ti0.46, Cr 20.31, N 0.021,Ni: 5.9^) high-temp, deformation followed by rapid auenching^produces.; v:<an increase in the yield strength and a bet ter resistance io boiling5ÓJÉ O ' ' '

- 64 - Contd.•••

c

as

.e

Strip lengths, 8 mm thick, have been hot-rolled at 900, 1000, and1100* with 10, 20, 30, and 40$ redn. in area and quenched, alongwith specimens heate<| to the same temp, but not deformed. .At 900• and 1000° the thermomeeh. treatment with a 40$ deformation givesan increase of 22 and 11$, resp., in the yield strength, at 1100°in the same conditions the tensile strength rises by 17$ and theyield point by 46$. Even without deformation, quenching produceshigh ductility;: for 1100°, elongation 35$ and redn. 74$. A certainimprovement obsd. in the results of a 24-hr corrosion test inboiling 50$ HNQ3 is connected with a more uniform Cr distributionafter the thermomech. treatment, as found by electron probe anal.

m.)»i s . ,

179. Mannheimer, W A; Paxton, H W

SOME EFFECTS OF.'NITROGEN ON THE RESISTANCE TO STRESS CORROSION. CRACKING OF TY.PE 304 STAINLESS STEEL WIRES.

Froc« Cónf. Fundará. Aspects of Stress Corros. Cracking 326-34? 1969.

The stress corrosion cracking of nitrided 304 stainless steel was.evaluated in boiling Mgdp environments. A significant increasesin. specimen lifetime is produce.d by nitriding in the 500-950* C

. .,, . r.angei' Electrochemical measurements suggest that the mechanism forimprovement due to nitriding probably results from a cathodicprotection effect. 16 references.

ORE,

180. Marek, M; Hochman, R F •

STRESS CORROSION CRACKING OF AUSTENITIC STAINLESS STEEL.

Corrosion, 26:1, 5r6» 1970.

Stress corrosion characteristics,ana the acidity of the solutioninside a crack.qit304 austenitic stainless steel were studied inboiling magnesium chloride, at 154°C. Fracture surfaces were alsostudied by electron microscopy using replica techniques and in thescanning microscope át magnifications ,up to 2600,X» Results showhigh acidity near the crack tip and the existence of both,trariscrystalline and intercrystalline fractures.

- 65 i-

184,

I': 1 8 1 . M a r s h a l l , . R P v . ' .

ANALYSIS OP FAILED 17-4 pH BOLTS FROM'THE ÉWGTR.

DP-1102 2 0 p . 1967 .

Analysis of five bolts of 17-4 p'H stainless, steel from the HeavyWater Components Test Reactor that had failed in service showed •that the failures were initiated by stress' corrosion. In"all butone of the failed bolts, and unstable crack size was reachedafter very little stress corrosion causing1 fast crack propagationand complete failure. In one bolt, the stress corrosion crack.hadstopped growing» IJany of the bolts, including all those that failed,were found to have been improperly heat treated.to approximatelythe H925 condition, instead of the specifiedHllOO condition. , Hieharder H925 condition is cpnducive to stress corrosion cracking in •the alloy. . No evidence for failure by fatigue was found.

185.

182.'. Marshall, O f - e t a l • ' ' ': . ' ' . v

CRACK PROPAGATION AT STRESSES BEL'07? THE FATIGUE LIMIT.- . :

. Trans. Quart 60:1, 112-13$ 1967. . ; ' , : . ' • '

Data are given for AM-350 stainless steel and for a Ti-8Al-lMo-IValloy to demonstrate that an assessment of cumulative damage infatigue must evaluate both initiation and propagation of cracks.Cracks will propagate at finite rates alternating.stress levels wellbelow those required to initiate a crack* - " ''.':

, íx1. Γ-J v j.

183. Masaki, Wj ..YosMhiko, M

• STRESS CORROSiOIi CRACKING OF AUSTÉIíIC STAIiíLESS' STEELS.' IÍ,';, :

ELECTROCHMIGAL EFFECT OH STRESS CORROSION. : '• / '"' ' '

Technol. Repté. 0so':á TJnív. ' lí, 137-4,8;- 1961. .'";; ;'ir , ; '

Stress corrosion'cracking of stainless steels under tensile stressin a boiling soln. of 42$ MgClg can be arrested by contact of lessnoble metals (Al, Fe, Cu) of suitable surface area.

- 66 -

184, Matsúshima* I

. STRESS CORROSION CRACKING FROM AN ELECTROCHEMICAL STANDPOINT.(in Japanese).I .

Nippon Kinzfoku Gakkai Kaiho; 8:1Q:, 655r-62; 1969Í :

The effects of contaminants pir the corrosion cracking of-metais,segregation in alloys under stress, formation of anode by corrosionreaction,..electrodepositiqn-and corrosion processes, potential changeduring corrosion cracking^ and electrochem, studies of stresscorrosion cracking: are reviewed.. 43.references.

éd,

185. Matsushima, I-, et al ¡ . , -.

.STBE3S-C0R|bsi01vT AND HYDROGEN CRACKING OF 17:7 (CHROMIUM-NICKEL)V STAINLESS STEEL. ....,•-

Corrosion, 22il, 23-27; 1966.

Stress corrosion results for 17:7 stainless steel, which althoughaustenitic may transform to ferrite ,on sold rolling, indicate theimportance of crystallographic structure on mode of failure. Inthe annealed condition 17:7 is resistant to H-cracking butsusceptible to MgClp test environments; after cold' reduction by2O?o it fails in bqtfi although only partially transformed toferrite, . In MgClo soln. cracking times may be prolonged by catlicdicpolarization, indicating a stress corrosion mechanism. 10 references!

511186» JMay,,: Jfl[/J*.'et a l , \-,••;.• . . - . . r

.-, ,,, SDBCRiTiCAL.'k.AW;'. GROWTH. • • . , . . •• . •

I r o n SMel I n s t . (London.)^ JPubl,, . 114 , 177-87^ 1968 .

, , TJie application of'linear, elastic-fracture mechanics to -the studyof subcritical flaw growth by stress, corrosion cracking and fatiguewere studied. ,The factor.controlling crack propagation is thestress intensity at the tip of the" crack. . The^benefits of thefracture mechanics approach, over, the more conventional quali.approaches are discussed and examples are given of the effect ofenvironment and metallurgical factors on the stress corrosioncracking limit, KISGC. AIL indication is given of the-applicationof this approach-to design considerations involving subcrit. flawgrowth» Under such conditions the crit. properties are crack*^propagation characteristics of materials. Development of improvedmaterials should be directed towards Jhe plane strain fracturetoughness, K I C, values and lower crack growth rates. . ..'

- 67 -

187, McCbllough, I Sj Scully, J.C

PITTING ATTACK ON-AN AUSTENITJC STAINLESS STÉEL IÍÍ SULÍHURIC ACID.

Corrosión Sci., 9:9, 707-709; 1969» • :.' / ;

. A.letter* The implications of 'tunnel' corrosion with'regard to thepropagation óf stress corrosion cracks and'in other situations', areconsidered. Simple interrupted charging, experiments (H charging ofstainless steel) on bulk specimens indicate that a small amount ofattack is cumulative and eventually gross pitting is observed. It iasuggested that funnel initiation may be a characteristic of certainmetals and alloys. Electron micrographs of a thin foil of H-changged304 steel showing pitting are illustrated and the ré'iévahcé .of ¡pitformation to tunnel and crack formation is discussed. 12; references.

•id

¡I11

168. Jfcdovar, B I et a l

THE STABILITY OP AÜSTEIíIÍDIC, CHROMUJlí-MANGÁMESE STEELS' AMD ÁLLQYS1GAINST. 'CORROSION CRAGKIMJ IN CHLORIDE" SOLUTIONS. ' ( i n .Russian)'

Avtomal. ,Svarka-19:5, .76-77} 1986.; . ' ' "

Specimens from s t e e l of the type JQil4G30 contg. Ni 1-23 wt.1 weretes t ed for corrosion-cracking under, s t r e s s by bo i l i ng a t 'l'$é0' i n a42 wt. jó MnCln* Tlie t e s ted s t e e l s were al loyed var ious ly with Mo2 .5 -3 .35 , Ti 6 .23 -0 .3 , were alloyed var ious ly with Mo 8 .5 -3 .35 ,Ti 0 ,23-0 .3 , Al 0 .25-0.38, or B 0.23-0.4 wt. fo. The aus tén i^ íc f 's t e e l HÜ1Í8N10T was used as a s tandard. All these_rmetal.s were 'p re l iminar i ly heated for 1 h r . a t 1100° and cooled i n ' a i r ; With 1steellKhl8N10T the cracks appeared a f t e r 24 l i r s . , 'while s t e e l s pf thetype Khl4-G30, contg> 8-23$ NÜ showed cracks ' a f ter ' :'¿~- 24 l i r a . " ' AtNi 3.58 wt . ia the d-racks. appeared a f te r 169 tos., while a t Ni 2 .0^or .T i 0*26 ana Al 0*30 wt.:?S improved r e s i s t a n c e tb 'general corros ion;however, i t increased the tendency to corrosión-'cracking;"1 " ^ t e é lcontg . Z. 2" Nil 'had' an." increased r e s i s t a n c e to" corrosion crackiijg, .and the addn.: of B (0.23-0.40 wi . .fo) made t h i s s i e e i s t i l l moré.;r e s i s t a n * provided Mo was "present ; (2.51 wt.' %) . ' ;; ; ' ; , \]

,189. ifcLaughlin, • B D.- : ' ;. ••:'•;--; • -'-' *-='•""''^

; COMPUTER SIMCILATIÓN OF .STRESS CORROSION3ÓRAÓKING.

Corrosion 27sg, 84-90; 1 ^

SC-RR-69-828 39p. 1970^

— 68 - C o n t d . . .

D.

theareof3f

Et .is

4nSgedLtices.

By assuming that the. electrochem. oxidn. mechanism of crackpropagation is not supplemented by mech. fracture or plaecic * -deformation, during the early stages of crack growth and that'the equil. rate of a charge transfer half-reaction, occurringat the interface between 2 phases, is dependent upon the localsurface tension at the point, of reaction, it is possible tosatisfactorily account for the following general aspects of stresscorrosion cracking such as the existence of an inculbation period,

•the existence of a threshold stress, the variation of incubation: :;time with orerpotential, and the variation of incubation timewith applied stress.

190,. Miisuno, Mj' Suzuki, T' , . '

STRESS. C0ER0SI-0N CHACKIifG OF' AUSTENITIC STAINLESS STEELS. III.STAINLESS STEELS M HIGH; TEMJERATDSE WATER. (In Japanese)

Nipponr Kinzoku' Kaiho 8:ÍO, 716^-21? 19S9.

The effect of ferrite on the stress corrosion cracking susceptibilityof "austenitic stainless steels, and stress corrosion crackingresistant austenitic ferrite 2 phase stainless steels, are reviewed.18 references. - . . - . .

a

teel

sion;

191. Holler, G E " "

UKDERSTAKDIUG STRESS CORROSION -CRACKIM&. - • ' - • '.

Próc. West; States: Corros. 3emin.,.25; 1-11; 1970.• " • • • r - ' i - - i ? " • - • ' " • ; • , - . * : ; • ; • : • • . , . ' - • . • • . • . " • ' • '

. Stress corrosión cracking .-is discussed as an educational backgroundfor metallurgical and design-engineers*.: -Stress- corrosion crackingis défkhed*and'its;mechanism the,,practical aspects,' its environmentaleffects^ its'effects on..various; alloy metals> and preventive measures areare discussed." Emphasis is. placearon austeriitic stainless steels.

1 9 2 . ISóntueliLé, ; J v ^' ...';^'i. ; .• '-••:-'••'• ¡ -• ''••-,':

- STAINLEIS- STEELS pi1 "HIGH: HráiTy=.; (in French) ;.'•

Mem. S c í i -Rev. Met . 65, 'S^.±--Q2 j , 1 9 6 6 . ; : '-••• •••••. • •/ •

The strüéturé of 18-8 high "purity stainless' steely prev*; írom zone-refined Pe and Ni, at ordinary temp, is'meV*~- •'V"1** a n * thus permití.significant hardening by temper-f»- ^VÍ^'A m\e£feo*B of th-¡* on thecorróelo^ behavior of t*>¿. l T 2 Z ¡ p t ^ ^respect t'p

" ' 1

1 9 3 . M o r i t a , S ' ' . " . ••••'__;• \ •'],,'[ ,. . . .. .,; - :/ •;••..•

STRESS CORROSION; CRACKIÍÍC- OP''COIiD-ROLLED AüSTENITÍC.STAINLESS STEELSI K J f a C l , S O L U T I O N , •• ...'' • :--y---J _ •': . .' ," •• • , ;,'.....• ;.

Nippon.Kinapku Gakkaishi 25, r,67-70j; 1961Í '. ..' , '..'•':•'.--'

Tiie effect of cold workingôn-the stress-corrosion crack sensitivity •in .boJLling NaOl with or without an addnl. oxidising .agent was .'studied id

' 18r8 and 18-12 -Mo "steel.' The transgranular corrosion.cracking appeared]in the specimen immersed in NaCl solns. provided that the soln. liadsuitable compn. for cracking. Comparing 18-8 with'18-12 .Mo in itscrack susceptibility, inmost of these solns., ,the';lat'ter, •contg»'1 :

Mb was more resistant to' the corrosion crackihgVwhich does'notce*acide with MgGlp spin. The preferential: attack of locallytransformed ferrite pílase was not so predominant as, in ligClg» Tli-econdition of corrpsion- environment wliicla is apt to cause cracking instainless steel depends on steel, as was shown. in; -jbhe'. caaeo of ¿pittingcorrosion. In addn*, the mechanism of crack' initiation wad discussed.

it!.

f

1 9 4 . ' M p r i t a , S •• , / v •• '••.-••'• ••'.:/• : ;. ' '"'.••."-..'' • ••', -, ' ": ":

STRESS CORROSION-CRACKIÍÍG" OP HEAT-TREATED, AUSTENITIc' .STAINLESS STEELS.

•Nippon Kinzoku Gakkaishi 25,- 675-9; 1961.' . , ' - " '-"'•-.

Tlie effect of heat-treatment .temp, on the susceptibility.of stresscori'osion cracking was studied by using a direct load *app. Tlie quant,relation between applied stress, and the. time to. failure, was obtainedon annealed 18r,8;in boiling 4 2 ^ MgClg. . At 400-800°, the., effect ofheating temp, on the susceptibility of stress corrosión;was studiedin -/boiling 42$ % C l a n d NaCl 'sQiir 'In'- WÔI s o l n t h e effectof

g p cpin -/boiling, 42$- %Clp, and- NaCl --'ei ' l l

'In'- soln.,, the effect. ofi thi lheating 'temp, .was¡.very:- small and the crackoqcurrihg in- this .soln.•

was;, .always _ trans granular.. \Iw-lia.Qi:s6iixi.'-i^pTiithe~^6atv&yVi< the';susceptibi l i ty , was defini tely increased by heading at"600 to' 800°,

'and' in;jbliist"".!emp..range, :the."patli!>df cradka".was"mainly intergranular ,Iμ NaCÍ'sóln., intergranularcorrosion was scarcely observed"oh thesurface ,.pf sensitized unloaded..specimen|•• thóugli the sp«eimen,-;t!nder •< ' 'tens i le s t ress: fai led by"inte^granulár cracking. In.acidi 'fiéa •' '•'-.copper sulfate soln . , which was -known,.tp âttack sénsit iáéd apeciíaen.sintergranularly witlôutany.. te'nsile' s tyess , "tlie. propagación f>t "'. -•intergrahular. crapk.in the: stresses; rsp'edíáen wap,>iauch. mbrje. seriousthan the penetration of ordinary iriteírgraáüXa:£^ cprrósionJthrough thesurface;/of the. specimeh». - The cpnaitiens causing' intergranular : -.;c r á q k i n g w e r ^ d i s c u s s e d . . . . •;•.-'•" '":-T~~%.•:'"•;, : ¡ T ^ " " ' ' " . - S " ' .- '•••-•• -V,- "..::•••

'-¿-'.-i- ' . - • - / ,

1 9 7 . 3

195. Morita, S

r .idtred

d.

..STRESS.CORROSION CRACKING OF SENSITIZED AUSTENITIC STAINLESS STEELS.

Nippon Kinzoku Gakkaishi 25, 87I«-5j 1961*

The effect of-sensitizing heat treatment on the susceptibility to. cracking and crack propagation in 6 -austenitic stainless steels wasstudied by using U-bend specimens. In general the stress corrosioncracke. of'austenitic stainless steel in chloride soln. are of•transcryst. natures However, some intergranular cracks were found in

..sensitized steel. In 42$ MgCl2 cracks were always' transcryst....in tl ', sensitized specimen as well as in the annealed one, and thecrack-sensitivity of the steel3 did. not increase by sensitizingtreatment» Intergranular cracks appeared in some of the sensitizedspecimens in NaCl soln» ; In this case, ste.els were more sensitiveto the stress-corrosion cracking in sensitized state than inannealed state* In extra-low-C or stabilized steels, however, thecracks were alwaystranscryst. regardless of the pretreatment of thespecimen, and the crack sensitivity of these steels aid not increaseby sensitizing treatment. The'c.d»-potential curves in chloridesoln. were observed on these steels, and the relation between theanodic.polarizability of steels and the.susceptibility and thepath of stress corrosion was discussed. The conditions causing..intergzanular cracking :were also discussed.

3.

196, Nadkarni, V M .

CORROSION RESISTANCE OF ATJSTEITITIC STAINLESS STEELS.

Bombay Technol, 18, 56-62; 1968.

A review of the resistance to corrosion of austenitic stainlesssteels, contg. a Cr-Ni ratio of 1:8. 15 references»

197. Namio, Of Terukuni, I

.: ON.THE RELATION BETWEEN STRESS CORROSION CRACKING AND CRYSTALLO-; GRAPHIC ORIENTATION-IN 18:8 STAINLESS STEEL, (in Japanese)

J. Japan Inst. Metals. 33:7, ?81-85j 1969.

, The stress corrosion behavior of 18:8 stainless steel was investigatedin a 42JÉ "MgClg solution. The crys tallographic orientation ofvatious.±a.:the specimen"^as: examiiiM. The bbservétl cracks wereclassified "into four groups; (i) pit-type cracks along (iii) or (100)plenesi (ii) liomer-Cottrell-type cracks along the (310). plane? (iii)dislocation^ pile^up Hype.cracks near grain boundaries; and (iv) crackswhich'were mixtures, of. (i), (ii), «tnd (iii), 10 references,

198. Haumann, F K; Spies, P ' "' .

FAILURE EXAMINATION:' INTERCRYSTALLINE STRESS CORROSION (CAUSTIC. .EMBRIKLEMENT). (.In German and English) . . . .

. Praktische Metallographie, 7:8,:459-463; 1970. ' .

The nature.of the cracks developing around rivet-holes in steam.boilers or brine evaporators is discuásed.in,the light of experience.gained with a variety of jbypes of steel over.along period» Such'crocks.¡are directly associated with intercrystalline stress corrosion.and this is readily confirmed by a study of their tracks-after inital.fetching» Increasing tlie Á1 content .of the .steels • employed aids

¿ c r , a c k r e s i s t a n c e * ••-. • . . . ~ [••. •.•"..'•:•

. 1 9 9 . N i e l s e n , N A • . : •' . ' ,. '

STRESS'CORROSION 1ECSMISMS..';' • •

. J... Mater. 5:4, 794-892} 1970. . . • . '.

A revdew- with 49 references of phenomenological stress corrosionfailures in stainless steels-aq.. chloride systems, the role of H asan embrittling agent, and the most recent theories of stress . !

corrosion mechanisms. . ' .

200. Ohtani, N ' , . : . . . . , , . ;

CORROSION. QF STAINLESS STEELS., .(in Japanese)

Denki Seiko 40:2," 106-17/ 1968.. " .

A review with 19 references on the mechanism of passive state formationjon stainless steels, the relation between the corrosion and the, structure of metals, the.role, of oxide film,in the passive, state,intergranuiar corrosion, pitting corrosion, and stress corrosion'cfacking of stainless steels.

r,201. Ohtani, Ni Iba, T, . -: - . - • . , • . • _

REIÍATIQN BETWEEN STRESS CCüROSION CRACKING. AND CRYSTALLOGRAPHIC •ORIENTATIONV.IN. 1.8-8 .STAINLESS STEEL.' (in Japanese) :- :. .

pcin Einzoku Sakkaishi 33i7» 781-5Y 1969. - .

Stress corrosion" cracking test of 18-8 stainless steel was carried :

out in a 43$ MgClg solii* v Thé crys,.taiiographic orientation ofvarious cracks ir the specimen Was- esp. exaod* . •

- 7 2 - Contd...

'<• f

Lenceiros ionLnital

The cracks observed are classified into 4 groupsj pit type cracksalong (ill) or (lOO) planes, LC type cracks along the (llO) planebased on the Lomer Co.ttrell barrier, dislocation pile up type cracks

1 near grain boundaries, and mixed type cracks. At the initial stageof the test, there seem to be many pit type cracks which are related

. to the corrosion of grain boundaries ..and slip lines. On thecontrary, all the types of"cracks are observed in large quantities atthe end of the test. Although the effect of applied strese on

•; fracture"becomes remarkable, at the final stage of the test, it requiresa-further study aV to which is more important to fracture, the

' tunneliforkationzeffeet by corrosion pits or the destructive effect of:J applied stress; ! ' *

202#>' Qkada", -H

as

KIRMATION-OP'CRACKS IN AUSTENITIC.. STAINLESS STEELS CATEODICALLYCHARGED' WITH BYDROGENi ' . , . . .

Corrosion'26:7, 183-6j: 1970. .. , ' .

'Type'304 stainless steel and vacuum-melted 20Cr-22Ni-Fe alloy wereheat-treated at 1230° for 8 hr in vacuum. After cooling andelectrolytic polishing, the specimens were oharged with H cathodicallyevolved from 5J6.HgSO with 10 g NagAsOg/l. at a c..d. of 0.5 A/cm2,AusLeaitic stainless steel is hardened and fine surf?x;e cracks areformed by cathodic charging. , Tlie cracks due to H form parallel to sliplines. Tine-to-fractüré of austenitic stainless steels is prolongedby cathodic polarization; hence stress-corrosion cracking of austeniticstainless steels is not directly attributable to H.

ormátion

ied!

203. ; :.0kaday'- H : et al. [, . .,

• •' F O B M T I O N OF'TRACES IN AÜSTEÍÍTITIC STAINLESS STEELS CATHODICALLY CHARGED ": - • W I T H / H Y D R O G E N . •-. • ' . . . . ; „ _ ' .:'.'' ;••..• . - ... _. .

Corrosion, 26:7, 183-86? 1970.

Experimental results indicate that austenitic stainless steel ishardened and fine cracks are formed on its surface by cathodic charging.It should be noted that..tlie cracks due to.H form lin^s parallel1 to slip.Tlie slip planes off. c. c. metals and alloys are (ill) planes and a. slip line is considered to be the trace of a slide of mtal on a slipplane. 5 Consequently, the. observations were interpreted to mean thatthe <jracks follow (ill) planes. The reason why the cracks form andpropagate along (111) planes is not clear. 10 references.

- 7 3 -

ü;

204.. Okazaki, M" et al

• STRESS'-" CORROSION- CRACKING OF. AUSTI!;NITJC 'STAlj, TEMPERATURE'WATERi ( i n Já'páhebe)' '": / ' / "

' Nippon.Kináokú .Gakkaishi 2 9 : 4 j ; 5^6-5; . 1965. ;

íiS S.,..STEELS IN,HÍGH-/ ' " "

Recently, austtnitic stainless stééls! are generally, jised to.buildup. at¿\ reactors. Hiesé steels can suffer "sürieós'' corrosion.:crackingunder certain.conditions of stress and corrosiveenvironment». On the

. 'other¿hand, the occurrence of só¿e troubles by the. stress-corrosioncracking of ausiienitics stainless steels-under unusual conditions wasreported. Exp. marine at. reactors are in danger of acceleratingthe occurrence of stress corrosion cracking tha-t. results .fr:om. ,the¿ • .repetition of wetting and drying of the reactor wall by cooling waterwhich moves with the roling of a ship, yari.ous auto.clave, tests were•carried, out, with the following results': ([i)> Wet-ting, anddcying. of'specimens accelerates the occurrence of stress corrosion cracking.(2) Addns* of lib and soln. .treatment reduce the corros ion rate*(3; Eie dissolved 0, chloride ions of rv/5 ppm. in water, and surfacecontamination of the specimen augment the...stress, corrosion cracking.

: n3 ; }

- • ¡ i !

.205. Okazaki, M et al/" " "';'" "' 'I ../ , . .-, • . • •

'' .- STRESS CORROSION CRACKING OP-AUSTENITIC STAINLESS -STEILS IN HIGH-•• . ' TEMPERATURE (PRESSURIZED) WATER. (In .Japanese) '//,.„;,:', ... :

ti. ... - : Nippohí Kinzoktt Gákkal-Si,: 29i4,- 340-45/ 1965. . i .......

Tlie conditions of stress corrosion of austenitic stainless steels inmarine atomic reactors were investigated. Various autoclave tests .;

were'carried out. Wetting and drying the specimens accelerated theoccurrence-of stress corrosion.. Addn..of Kb and,spin, heat-treatment.reduced^the corrosion rate, but dissolved Q, chloride ions:(<V 5 ,ppm),and surface, contamination of the specimen all increased stressc o r r o s i o n . . • . '. ..•.....'• • .-",,'."

206 . O n d r e j c i n , R S

• '/MECHANISM FOR.STRESS CORROSION'. • REACTOR SYSTEMS.- ..' ' ¿ . .

0?' STAINLESS 'STEEL:I1T/

DP-1089 25p,, 1969V

- 74 -

O 'I . . !

agthe

onwas

rater•ere

aceing.

207. Oridrejein,' R S . . ; -

MECHANISM FOR STRESS CORROSION -CRACKING OF STATNLESS STEELS. INREACTOR SYSTEMS.

O, ;.'.:;1>PT.1Ó89,;.,;. j.-¿5p.-' •' 1959..;; .. . . .

A mechanism for chloride stress corrosion cracking of Type 304stainless steel that has been sensitized, pickled and dry groundinvolves the chloride-bearing A^Og present in the moderator-.CQolant. system of savannah River reactors. Chloride is absorbed by thek%p9a .during its formation.on hot fuel cladding} Fé, an impurity

..• in.tñe cladding,- greatly enhances chloride absorption. AlgO3 spalls•-.;; and is transported by the coolant to the stainless steel surfaces.

Chloride is released from the AlpO, by the acidic reaction atanodic sites.on the steel. The chloride ion is attracted to thepos. anodic aite and initiates stress .corrosion cracking. Crackingof susceptible stainless steel by this mechanism can b. reduced bycontrolling coolant pH (pj)) between 5.0 and 5.2 to prevent generalrelease of chl"oride.v.and\ by avoiding addn. of chlorides andchlorinated hydrocarbons to the reactor, and by .blocking abodicsites by inhibitors .or by changing the potential of the stainlesssteel. . . " • ' : •

inS ' '.:he ' .mentppm),

208. Onishi, S et al -

STRESS CORROSION CRACKING OF AÜSTENITIC STAINLESS STEEL IN HIGH' • TEMPERATURE1 WATER, (in Japanese) ' , •

Mitsubishi^Nippon Juko Giho.4 (Des.), 131-44; 1963. "•

Recently, austenitic stainless stetl is generally used to build at., .xeáctorsi ' It has been reported that-troubles occur from the stress' corrosion cracking of austenitic stainless steel under someconditions. Specifically, in marine at. reactors there is fear thatacceleration of stress corrosion cracking*will result from wetting¡and drying of the.reactor-wall by. cooling water^according tó the'rolling ;óf:,ships~.. .-•Expts. were nade on:the. following maters; effectsof. the wetting and drying j.of specimens % effects of the chfcm. compn.,

. welding, and heat treatment of materials?-and effects of the purity. : of water ::ánd the surface .contamination of specimens'. --.

- 75 -

" I

209. Orman, S

RAPID TEST FOR STRESS -CORROSION CRACKING; ' •

Corros. Sci..9, 849-61 $ 1969. • ' :

. . - . • * - ' " • - - • • • - . . • , ;,••- ' • \ • • ! - . ; • • . . ' : . . . .

210.- Overman, R F ' . ; ' : .. ::•

USING RADIOACTIVE TRACERS TO STUDY CHLORIDE STRESS.CORROSION CRACKING •OF STAINLESS STEELS.-

Corrosion, 22t2, 48-52; • 1966. - • . •/ ' ' ." -• : LI • ' . ¡. ' •

, Radioactive-r tracer techniques indicate the presence of•charged:areason the surface of steel which may be created by a high contín. of small

.. sulphide; inclusions*. In one. charged area 7 x 109g CI*'-Tías sufficient.•to initiate corrosion, and thence crocking, on a stainless steel surfacestressed by grinding.. 16 references» • . "

211. Ozdemirel, N . - • . .

INTERGRAIfULAR CORROSION IN AÜSTEIIITIC STAINLESS STEELS AHD HOW -IT CAN BE AVOIDED.- , . -•:-.• . • " ••

Demir Celik 17:8, 256-61; 1968. . ^

A review is presented on the mechanism of intergranular corrosion andits prevention. 3 references.- " .:

212. Phelps, E H; Mears, R B , > , .

THE EPFECT OF COMPOSITION AÜ3D STRUCTURE OF• STAINLESS STEELS ON. •RESISTMCE TO STRESS CORROSION CRACKING. - . •

Intern. Congr. Metallic Corrosion, 1st, London, Engl..319-27? 1961*

In a study of ;the stress corrosion behavior -pf.auaténitic -.andferritic steels in a no. of corrosive environments :and includingthe effects of anodic and cathodic polarizatioií, .12^ Cr steel with

. Mo .and V and 1ype 410 niartensitic steels and types, 302 and 304= -., austenitic Steels wer.e:,\tes ed5 .tests were effected in boiling. 42?SMgClg and rpoia-rtemp. -tests, were made in a no. of Na salts aerated withair, in Z^ NaCl: aerated with 0, -iñ.lOJÉ ;HaCl with HsQp, in-10^ FéCl^,in Z% NaCl satd. with HgS, and in 3^ NaCl with 0.5% AcOH and satd.with .HgS during 17Q0 lars. The 12$ Cr steel was very suiebeptible tocracking in a no. of the media in.which the tempered 410 and annealed304 3teels were quitestable, a substantial no. of anions otherthan Cl~ appeared capable of effecting cracking in the former steel,often in a time shorter than that' required by 01" soln. solns. near :neutrai of slightly acid were more prone to causé cracking.

- ?6 -• Contd...

Polarization tests on type 302 steel appeared consistent withcorrosion along an active path through the steel, while at cathodiccurrents 0.5 ma./in.2 a H embrittlement' mechanism appeared to apply;with the 12$. Cr steel tlie results were inconclusiveé

213. Poboril, P et al *• • ' ' • • • • • • O F , .

., STRESS.CORROSION CRACKING RESISTANT AUSTENITIC STEELS, (in Czech)

Hutnicke Listy 21 ;7, 484-92? 1966. •'.."}•:••"•• • ' *

In the .tests carried out under const, load, stress corrosion crackingresistance is detd. in the soln. of MgClg ¿2 and CaClg 40 at 105-110°.Two 18/8 Cr iii steels (one of them stabrillized with Ti), one Cr-Mn .steel contg, Mn 16A5, Ni 2.08, Cr 19,29, and N 0.47$, as Fell as3 Mi-CΓ austenitic heat-re3isting steels contg. Mn 16.7-19.4 andCr 7*3-11.1$ are examd. Typical failure in the' stress corrosionresistance is shown by the tests of both Cr»Ni steeis. Low corrosionresistance is found in the Gr-Mn steel with the addn. of N. All Mn-Cr steels exhibit in the given condition" high stress-corrosioncracking resistance. 36 references» "

214. Podobaev, N I

TEE MECHANISM OF DELAYING STRESS CORROSION CRACKING BY CORROSIONINHIBITORS. .

Z h . ' P r i k l . Kliim. 36, 362-7$: 1963.

215. Pogodin, V P e t a l . . . : . '

- INTERCEANULAS . CORROSION "'AMD CORROSION CRACKING OP STAINLESS STEELS INAQUEOUS MEDIA." (in Russian) . . . . . . . ,

Met. 'A;., 7103:720068,.422j 1970. . . ,

Inteigranular.corrosión and stress corrosion, behavior are reported .for austenitic, ferratic and,oaftens.itic stainless steels in pure,

: waier, :vá.teanrahd solutions of salís, acids,and alk/ilies¿ Tlie • «corrosion-testing conditions include those prevailing in the water-

' "'' arid s^eam-coqled reactors,.*power stations alid in the chemical -,,.-.industry, behavior, such'as media composition, composition and l ¡ *structur,e"&£'.steels,:liea;t treatment, stresses and;radi,ation effects.

•..'-'. Coirosio^i'. preventive.methods-'-are reviewed, including alloying ^ this:.steelsrwith,elements such-.as C|7i,ITbyTa}&r»HirNyJfof.Siy¥f.l7tjl6i andr,B.

- 7 7 - • • • X ' |i

I ',•'

216. P o u i l l a r d , . M .-. . . . .••:. •. ,.-•••

' CORROSION OF AüS'IENITIC STAIIÍLESS STEELS UiJDER T.MSI0ÍÍ.

Corrosion Anti-Corrosion II, 264-?j 1963.

The corrosión oí* austenitic stainless steel under tension in thepresence of chlorides* HgS, ifagS, alkalis, -and pure HgO was considered.Tlié corrosión attack in chloride-contg. soln. is esp. strong, forwhich reason the temp, is kept as low as.possible, and tension whichreach the elastic limit of the steel must bé avoided. The use ofsteels with 2Ó-2fo'%i and Zfo Si. is recommended when the action ofchloride's is. to be reckoned, with, as well as autenitic steel with a fewpercent ferrite. • ' ' ' .

217. Pourbalxy M dej Huebner, ¥

STRESS CORROSIÓN OF TWO STAIITLESS POTENTIAL PRESSURE VESSEL STEELS '• ' WITH MIXED; PHASE STRUCTURE. . ' ".

6th Scandinavian corrosion Congress Geeteborg, Sweden. 24, 1971.

INIS -af-151. 1971, lip. - ' ' .••'• : • -

21

221

2 1 8 , Prazhak", ' ' M e t a l

THE ROLE OF AMON ADSOfiPTIOU IU THE PIT'IIiTO AND CORROSION CRACKINGOF METALS, ( i n R u s s i a n ) .

SI

and i n NaOH

Zashchita lletallov, 5:4, 371-75; 1969. .

Potentiodynaniic polarization of 99;95?í Hi in O.^

solutions contg» various additions of Cl" ions, was used to obtainvalues of the.pitting potential, E » The..ability^-of a solution.tocause pitting corrosion is primarily determined by the surfaceconcentration of the activating ion (CI"") and this depends not onlyon its analytical concentration in the solution but also on, the". .adsorptionequiiibria'of all the components of the soluiion. The. effectof the activating and passivating ions on.Ep can be described by f<;the use of the freundich. similar'relationships cab be obtained-between th¡the concentration of' passivating ións, CrO^"", and activating ions,01" (as FeCls), in.the pitting of 18s9 Cr-Nirstainless steel. 'Preliminary results on the corrosion cracking of thia steel in WgClgand of Al-Mg alloys in NaCl of various pH values, indicate: that . *competitive adsorption effects also' have an effect in the first stageof the process. . 19 references.

- 78 -

red.

ih

few

219. P roc te r , R P Mj Paxton, H W

STRESS CORROSION. CRACK;; INITIATION IN 7O75-T6 SHEET IN ORGANICLIQUIDS.• ' -:

J . . Mater . , 5 :3 , .602-4 ; 1970.~ '

Stress corrosion f&i'lures occurred in 7075-T6 alloy U-bend specimens, exposed to dry ethanol environments for up to 381 days. However,

no, signs of stress corrosion cracking were visible on specimens exposedto. carbon tetrachloride after about 750 days.

E ff . .. , • \

THE MECHANISM (s) OF STRESS CORROSION CRACKING,

liet.' Soc. Conf. 35, 351-4^1} 1965.

Tlie major theories of s t r e s s corrosion are reviewed. I t i s concludedthat a,single; generalized theory can be ruled out. The charac ter i s t icsof s t r e s s corrosion cracking in several meterials including,A1 a l loys ,«Cbrasses, mild and austéri i t ic s ta in less s t e e l , and Mg and for th .In Al al loys the fa i lu re i s considered to be nech. jo£ brass i s thoughttp_cfail An. ce r ta in ammoniacai environments by the continuous .

t formation.and rupture of a b r i t t l e tarnish layer. In the l a t t e r system' aiSecopd mechanism i s a l so operati'v'e", probably "mostly chein. in .nature.. , ' 9 8 . r e f e r e n c e s . ; - < . - s -•••-.. . • - > ' - . '< '-" " •''' '' " • • • _ _

)H

;2 2 1 . _ . R h o d e s , ,^P. jt .. •;. •;•.• '• '..•:•-• • • ' .-•• ' •_ ••

-MECHANISM OP. CHLORIDE' STRESS CORROSION • CRACKING' OF AUSTMITJC

E ' ' ' '

ffect

feween th|

age

Corrosipn 25:11, 462-72; 1969. . • .

Electrochem. studies were made in aq. LiCl, 3%Clo» and MgBr« solns.and in ZtttClx/KCl molten salt to clarify the corrosión reactions

related to stress corrosion cracking '(SCO) bf aiistenitic stainlesssteel and better to define environmental variables, crit^ to cjilori.deSCO..; .Type 3Q4..stainless-steel- electrodes were used, and complementarySCO was obsd. in coned. MgBr2 solns. HgO must, be present in theelectrolysej- SCO? did not fccüVin dry molten ZriClg/KCl. H evolutionfroá Qoprpding specimens^may te facilitated by anodic polarization*Present].,,studies,do not -support a model equating crack propagation withstress/aspisted anodic-dissoln. H evolution occurs at the,crack.tip and. this is a crit. precursor to crack initiation and propagation.A model of SCO.requiring H evolution at the crack tip is proposed,with emphasis on the effect'of anodic reactions within the crack inmaintaining high acidity near the crack tip. Recen* publications, suggestthat the role of evolved H in SCC may be related to formation of Hinduoed martensitic platelets along paths of crack propagation.

' . • " . ' • / " - ' 7 9 - • • ' ' " . - • • ^ - ' , • " •'

2 2 2 . R i d e o u t , S E . , , - •.. ' -• • \"'•'•"'•"' x

STRESS CORROSION CRACKING OF TYPE.304 (l8#8.):.STAINLESS::STÉlL"íííHIGH-PURITY HE.AÍT' WA5JÍÜ. '. ' .;''•'- - '-•••• ' '-

Nat. Assoc. Corrosion Eng. 2nd Internet. Congress on Metallic; .Corrosion, New York,- 159-71} 1963, Í966.

Laboratory tests, duplicating.heavy-waterIreagtor moderator experience-with stainless steel outlet .nozzies, deinont. trated-that Type 304",Iβ18 Cr-Ni, stainless 3teel sensitized-and .pickled-i'n-HNOilHF Iβextremely susceptible to stress-corrosion cracking in water with a

•• very- low- Cl-iorx concn» Stress corrosion cracking may be caused., if ,grain-boundary pickling crevices are present, at concn'»

<!bf ,CÍ¿" :belbw

the ppm level though the time to initiation may be years.37 references. ;;.. "• ¡ ... .''••> • :- -' •-•

223. Robinson, J Dj Crackr.ell, A

. AVOIDANCE OF STRESS CORROSION CRACKING 'iHwHEAT -EXCHANGEES. -

Brit, 1,132,014 ;i968'

Tlie forinstion of gas or vapor bubbles and thus sttess coriosi'on1,.cracking in heat exchangers made.-'.of jaustenitic stainless1 's tVel 'conrg.Ni ¿J >45 and o t h é r ^ e l e m ^ t B ' S p r S ^ ^ S ' í 6 ^ ^ ^ 3 ^ * ' 6 ^ - - ^ ' - ^ ^•coolant tó á: pressure higher than its vapor pressure at'¡ toperating temp. The concn. of the corrodant impurities esp. Cl"and NaOH should be ¿, iO ppm./impurity. Tlie corrosion inhibitor.,concn. (Na_P0.) should be s\j?> timss the coolant ion concn.»K stress"

i * *i . • . • -

corrosion cracking of British Standard Specification 3605, i1 ,; Sfis pigmented for long periods by-submitting the' cooling. HgO contg.30 ppnu Na_P04 and operating at 120-150° to a pressure"of 400 psia.

2 2 4 . Ronnq.uif?t, A . V ." ' ' - \. . ; . . . : . . , " -.v

THE EFFECT.OF. ORDERING k l D -STAGEING-FAULT ENE1GY ; ON TÉÉ SENSfTiyiTYTO STRESS-CORROSION CRACKING. ..V-, . • ' ; . Vo: ' .v ;-- ; - > ; " " '

Proc. Cc|nf> iundam.; Aspects of Stress Corros,. Cracking* 31'8-324jl969»

The cOrrklstiqn between suscept ib i l i ty to íi.taíess"corrosion crackingand-properties'-of'the abetal súch;eas, stáckinig-fault energy' ¿nS ' ;;ordéring|áre discussed. Detailed consideration i s given* tcr; prqb'lémsassociated with -the mea,su-réd,of the^sta-cking^faul-t .enérgy-üsiñg'"''the node ijbéohnique. . Resizlts show, that there.; i s ;a great uncertaintyin node mteasurenien-fcs and tiierefore considerable doubt'as to thesignificance oí correlations aE<>ng alloys»'^ ^ . .-ro>..: f••' „ ' v

" - " • • • " - . = . •' . - ' . • . . ' • . - - , / * . - ' • : • , ; . ' : Í : > ^ : ' ' - Í ' '•

• , • . . , - ' - • ' — ' 8 0 • - • ; • - . j ' : - ' . : ; - , r ' . ' .- ' . ' • • • '. • ' *.\>ionW*m¿ •

' 1 ; -;/ ' - i>,

The .suggestion is made that correlations of stress corrosionsusceptibility ,only with facts associated with deformation processesmay be insufficient to specify.the cracking susceptibility. Specialattention should be given to/the combined effects of complex formingtendencies-.-of ;tíie environment together with factors affectingdeformation processes. 29 references.

225. Ronn^uist,} A ';,. - -,

STRESS CORROSION IN METAL ALLOYS, (in Sweden)

Svensk. Kem. Tidskr. 78:6/7, 304-20; 1966.

A review; of exptlvtechniqu.es and proposed theories. 51 references.

226. Roy, A et al -

... - CORROSION CRACKING, OF STAINLESS STEEL VESSELS OF AN AIR LIQUEFACTION.PLANT.-.; -> - . • '

Technology; 5:1',; 45*9j 1968. .

investigations,',were made'by X-ráy diffraction, theriaomagnetic andelectron microscopic techniques on samples collected from theleakage points of an air liquefaction plant. In each case thefollowing three regions were chosen for examn.: weldmet, material-adjacent to the weld, and parent metal far away from the weld.The x-ray, diffraction..photographs of ;t.he parent metal far awayfrom tire weld,- of:;aJ|l .samples, showed austenite as the only roryst,;pnáse¿'"-••" But, the- diffraction photograph of filing dusts collected. from, the material adjacent to the we Id., and weldmets revealed smallijnts. of ferrite' ¿lo'jtig with the austenite. Tlie photographs alsoindicated lattice strain.which was.increasing from the parent metaltowards, the weldnjetó* Thérmómagnétic anal., corroborated the :findings' bf the. x-ra^i diffraction anal. '• Results showed that, crackingof stainlesssteel' vessels was' diie. to stress corrosion caused by..residual'Stresses and! chlor,id"é: environments. .. ' , - . .,.-:•

22?. Royjiéla, J -J •; ' . ^ ' J ^ V - V -.'J.' - \..'c.-:\;,1 -STRESS-CtoBROSlO'HS (in; Spanish). ; .'..' \,. '"• '; ';,''.

Quim. Jnd v (i&drid) 16 Sí i , 65-7} Í97o'. ;, ,

The factors involved in;-the chem. and • eleetrochem. corrosion ofs tee l reinforcement andi| the result ing/effects on structures arediscussed. -

- 81 - Contd.

4

Portland, and alumina-'cements behav'e.cdifferently in this•;r.éSpéct»~,Tlie,;,addn¿-í.bf-.';Cla,CÍp as a hardening .accelerator increases.'the ;-'-'•

.' probability;of •attack. Cases, of ;;corrósion- resulting f rom'design" '[ ./'and construction faults' are, also described; ':.The difficulties;^of •

establishing standards, and me.thods of test1 are e¿amd#:and-'•practic'alrecommendations are made. Direct protection is afforded by li; 'coatings or inhibitors. Indirect protection is obtained by goodpractice ensuring that the concrete is uniform and homogeneous.CaClp should not. be used, and the mixing water should be free' ;-from sol. Salts. •

230. Ryabcl

2 2 8 . H o y u e l a , J J ' / , • - • • . .. ••: ••• « : . / . • - ' ' : I " •• - } ' "• - " " • • • ' ? ; •

THE EFFECT OF ELECTRO CHEMICAL -POTBHTIAb- OH THE' STSFSS:- CORROSION OFIRÓJSf-íílCKEL-CHROMIIJM ALLOYS. (in Spanish)

Revista Met., 5:2, 122-130; 1969. . . ' ',•:'.

stainless steels .and 50:Mgh-purity:'Fe-Ni-Cr alloys werestressed.in boiling Mgcig solution and potential/t curves obtained.In some tests a constant potential was applied. Pure alloys were foundto. be more resistant than. the.equivalent comme.rcial alloysj Ni

improved corrosion resistance but Mh, Cr, Mo, Nb and 0 had an adverseeffect. Conditions for the cathodie-protection of different alloysw e r e e s t a b l i s h e d . " 2 3 r e f e r e n c e s . . •:._,.;.;,. "; ••• ••-•-- ;••'- • -: • '•':/' '-'•-

2 2 9 . R o y ü e l a y - . ¿ J . ,'• • /-•'-'•.- .",'. '"' ";;'''.'', ' ' . I ".;.-' '-•.."•*.' ,-'.'"

' STRESS" CORROSION OF IRON NICKEL CHROÍECülí- ALLOYS ;AÍI3). TPiHÍATIQ^^¿M;': INFLIJÉNCÉ'OF'E.LECTRqaHEMICAL^POTEFJIÁL ON"THESE'T;ESTS; ( l ^ Span i sh ) . '

Rev. Met.- : 5:2, ;122r30;

A.stress corrosion study.was made of fa. series-"of atáiriless steels, andalloys ;(Fe and Ni 6-65^,- !Fe-5.Cr; Pe,, iii 5-80^; nd' 5r4P?É .,CrX.'i'-:.:Íhe"tests were' made in 42^'boiling MgCÍ¿. .The .variation and e,ff'ect, of theelectrociiem. potential were 'measured. . Special all py's,. were more. ,

corrosion resistant than coin.; on'es bf similar Ni arid. Cr contents. Tlie. determintal effects of C, Mh, and Nb was noted in the 18/8 steel.Ni increases the stress corrosion resistance while Or reduces it, • r . ;•',In alloys where Ni was wholly or partially substituted by' Mh thetime to failure was considerably less. Time, and type, of failure werederived from the initial part"of the potential-time curvea. Thesecan be used also for considering.Hhe possibility of..cathodic » 'protection for the material-; /. 'i'-: ,"•''- y '- . '

.-82 -

231. Ryabc

2 3 0 . Ryabchenkov, A V} Gerasimov, V I

...TEE: EFFECTS/OF NITROGEN, .PHOSPHORFSj" AND' SULPHUR OiS'TRE RESI3TMCE OP.CHÉOÍÍIÜM-HÍéiíEL/AüSTENITIC STEELS TO G0RH0S10ÍÍ 0RA0L1EG.' (in R u s s i a n )

Zashchita Metallov, 6:2, 134-144; 1970.

The austerütic Cr-Ni-Fc alloys of type Kh20M6B have a high resistance"to..corrosion cracking in various environments; with a view to usingsteels of, lower Ni content,-;-the effect of K, P, and 3 on'theresistance to" this rfórmu'ó*f-attack was studied in steels of lowerMi content .-e.g. in 0KÜS0N35B prepared by open-hearth of vacuummethods. . Tests, were made "in '-(i1)" boiling 42$ % C l g (l54

eC), (ii)• '25j6'NaCl-0;.53¿.K2Cr207 át

: 2Ó0°C and 16 atm. in autoclaves, and (iii)aqueous solutions contg'w) CI 200-0 0.3-6. O'mg/l.at 320J>C and 115 atm.in autoclaves. The tendency of this'35$'M steeí to corrosion

cracking is increased by if, and particularly P, and these shouldJl> 0,03 andlji. 0.01$, resp., with N + " P ^ 0.035?£ for open-hearth and"%. 0,05$ for vacuum steels. Steels coñtg. ITi Z.30$ are susceptible.:.„to córrosidh cracking'even iyith very low II + P contents. S has littleeffect on the susceptibility to corrosion craciking and the usualindustrial permitted level of S 0.02$ does not. intensity the attackirrespective of the Ni content TTXth either stabilized or uhstabilizedsteels. Tlie e-ffec$S' of N and P on the resistance to stress corrosionare apparently connected with ordering which leads to changes in thedislocation structure and to the appearance of electrochemical ' .

.. heterogeneities that promote the'ihitation and development ofc o r r o s i o n c r a c k nuclei.-'"'-'-": •••••••• -.v. -• •

231. Ryabchenkov, A; 7$ Gerasimov, : V I -•'•"'- " . '• "

THE EFFECT OF ALLOYING OK THE RESISTANCE OF AUSTENITIC STEELS TOCORROSION CRACKING IN CONCENTRATE]) SOLUTIONS OF CHLORIDES..., (in Russian)

. Zashchita Metallov 1 (l),48-54| 1965. „ ;

Testff were made in a soln. of 25$ NaCl + 0.5$ K2Cr20? ; a t 200°, and. .i e atnu and in boiling 42$ MgClg. : After 2 .5 , 10,. 25, 50, 100, 150,2,00, 300, and 500 h r s . , observations were made with a loupe (7 X)}the c r i te r ion was the appearance of pracks. The resistance, of ,. ,.Cr-Ni and Cr-Ni-16i s teels to" corrosion cracking ihcreases with ":

increasing Ni content!}: a t <f>»>45$N'i the. ste'el i s riot'.p'rpñe, to . ',.- .: corrosion cracking. -Wi; and Mo show a áégi :effect oh'the resis tance

of high-ffi'• ai.éólg-j,""Under a tehsión/of\:53-7.¿55,kg./inm'¿2. obtain ..s t a b i l i t y iitt the long fun (5Ó0)hrs.) in boiling 42$ itgClg^e.olns.

, Steels with lower M contetft^ show nearly the,>ame^ Hmit for the long-. . r u n r e s i a t a h o e - a s s t e e l . • " '-'•' -;''''.'••'• ". ''' '•''•." " .- "••.-•"'. '. - •

- 83 -

2 3 2 , R y a b c h e n k o v , A V} G e r a s i m o v , V - I -. . . .-.. ,; ' . ' . . •• : : :*. .?.-v* ••••

,, . -EFFECT-; OF. . .PRELB' i lHARY C O B R O S I p N ; . UNDER S T R E S S , O F THE. F A T I G U E .STRENGTH; •' .; • O P A Ú S T E N I T I G S T E E L S . ; ( i n R u s s i a n ) , , . . • ; . • • . _ .,.:; -4, ••• ¿v.'.'r; •:•.-.. "'.

Z a s h o h . M e t a l . ' 5 « 2 , 2 1 9 - 2 1 $ , 1 9 6 9 » . .:; : . ' - < •? " .„• ,"..::: :-• ' • • »

...The effect of.preliminary corrosion -under stress , in a ¿boiling V -0 ' •' ^..MgQip ,solnf. on the fatigue str&ngjsh of Khl8Nip.T and .Kh20N45B-.

steels ..(In the open) was investigated. In the case of Ehl8N10Tf-• the pre.liminarjr c.d^rpsion, under ..these-conditions, leads,'after •i-5^ ,!hrs', to- á marked,decrease.in the •steel.-.fatigue strength owingto.'.the'/formation, of "submieroscopie corrosion .slots and corrosion

., ,.mi.cr'ofxásures. -'.'This effect was not-observed, with ¿liáOMeB due to1 its remarkable real'stande'to stress ,corro,sion ;cracking,;;

235» Sa

SO

!l

2 3 3 . R y a b c h é n k o v , . ' , A . V ; N i k i f o r o v a , ; V JI •• . ¿- ,"•• ;.,¡- -!":'.,.: '.".,.:' •''••-

" ' . ' - , • . ' ' - " " " ' • ' . ' ; • • • ' - ' • • . • ' " - . - • : . • . . i . : ' , « : . - - ^ - " . • " - • . • • - v . ° ' i • • • ^ - < % ' - • • . . ' •

CORROSION OF STAINLESS STEELS -UNDER 'STRESS*. RQLE :.QF,fELECTROCE^álCAL. FACTORS INCORROSIO1Í CRACKIiTGOF AUSTEKITIC; STEELS». ¡. . .--. : •. '"'

. ' Me'zhkristal» Kbrroziya i Korro2iya Metal-.' y Napryagh* Sostoyanii,1 .;• Vsekj." Spv. '.Nauchn,- Teklin. Obshchestv, 161-78}:. .1960... frC ; ••..: .- •••-

Experiments;'with three types,;:of; austenitic steels (ELG9, lGrl8N19Ti and15-13-3ÍÍ) of different susceptibilities to stress corrosion,¿showedthat the effect of stress destroya the protective oxide' film.andcauses electrode-potentials to become less noble by 30-80 mv. Instress corrosion, a stable potential difference between separatemicio-areas is set up and is the main. cause; of corrosion bracking. ---:

The role of stresses in corrosion cracking is discussed and defined.

234. Ryabchenkpv, . A T et al' " - ; ,

STRESS CORROSION OF AUSTENITIC STEELS. A1I3 ¡rHE MAIS FACTORS INFLUENCINGTHE PROCESS, (in Russian) . -. .. , • , . -, .:i; .-;r... .:

•'Zashcliiia;Metal. ,2?3,-367-78;. 1966. -V. . . . / ; / • : r-n-)\i

-A detailed ,review concerning.the nature and;-mechanism -of corrosion "cracking of auóténitic sieels "in Cl~ spins, an^-th^inain factors -influencing stress corrosión. Tlíe conventional\factors .affecting ?austehitic steel crackiag are classified in 2 grojips: external-.. " ,corrosive me ii'á an'd«phys*-chem. properties, of íhér metal itself.' Thebhea. .compji.' is assumed i;o be of major ¿importance, and the effect ofalloying components of austenitic steels (lift,Mo,Si,C>lB|Gr^Ti,lFb,B,P,and Ni) is sep. considered. Exptl. investigation methods are omitted. ;.86 references. , ' ' v

236¿' Sai

• TH]

Me*

- 8 4 -

235, Sandoz, G et al

SOLUTION CHEMISTRY WITHIN STRESS CORROSION CRACKS IN ALLOY STEELS.

Corros. Sci. 10:12, 839-45; 1970.

Measurements were made of pH and metal ion conons. in the soln.within stress corrosion cracks in various research steels including0.45$ C, 0.29$ C + 5.8?o Ni, 0.28^ C + il.6Jfi Hi, 0.32$ C + 5.Sfo Ifa,and 0.31$ C + 1.9$ Mo steels and com. steels including AISI type 4340,17-4 JH,- 13 Grv8 Ni-Ifo, 9 Ni-4 Co-0.2 G, 12 Ni-5 Cr-3 Mb, and 18 Ni,the latter 2 being of the maraging type. Cracking was effected "bystressing under 3.5$ NaCl, pH 6.0, and 25°.. In addn. to the use ofindicator-impregnated filter paper for estg. pH and detectingFe2 + and Fe3+ ions, quant, ions, quant, chem. techniques weredeveloped ;to det» the wt. and hence the proportion of metal ions in

•: sóíh» All steels tested developed a pH of 3.7 in the soln. near ther-^s^ress -corrosion crack tip; Fe^+ and Fe3+ ions were in doubt due tov acess of 0£ during anal, processing;- the other data suggests a very low

ipe3.+ "conch, within the crack., Alloying elements in the steels werefound in -the' s.olh. hear the crack tj.p in approx. the same proportionsas -in the original steel compn. Preferential dissoln. of JMh was

• - found due .-to. the crack tending to run through Mh-rich areas, Thedata'7 suggest a predominant role bfj-hydrolysis of Fe ions i:i detgi

•- the • acldi-iy" b_f the soln» in the crack with alipying elements having-' '"• li"bfle effect. Activé metallic surface in the crack is anodic.

Grack acidity, appeared independent of bulk pPI.

236;'-•••Sáíiti-Bi R De; Casarini, G '" vT,,,

• THE CORROSION OF AUSTENITIC STAINLESS STEELS, (in Italian)

Met. Ital., 60:3, 159-65; 1969.

Details are given of corrosion failures of stainless steels indifferent environments. Exjunples includet intercrystalline :

corrosion in the heát-affected zones near welds and the selectionof materials and, heat treatments to minimise this; .pitting corrosionin the "presence of.''01, Br, and SgO^, and the beneficial effects of

- MovadditibnsL in* xeiation to pitting corrosion; and stress cor-.osionin tubes and" pressings and the improvement of stress corrosion-resistance obtainable with'increased N4 content. 22 referepo.es..

- 85 -

237. Saxéna, M N • •

MECHANISM OF STEES5 CORROSION CRACKING 1ST AUSTENITIC STAINLESS STEELS.• \ . • ' • * . • • u . •> ••• - •-•

Uhiv. Microfilms (Ann Arbor, Mich),Order No. 65-4838', 91 ppj , " ' , '.•:•-••••;.P i s s . A b s t r . 2 5 ( 1 0 , 5 8 4 9 } 1 9 6 5 . . -•<•••

238. Saxena, M Nj Doda, R A . • .:

. TRANSGRANULAR-STRESS CORROSION CRACKÍNG iffiCHAHISMS.IN. HIGH-FDRIiPYSTAINLESS STEELS. v • . ",', .

Met,. Soc. Cbnf. 35, 455-79} 1965. . . .,.-,, ..,,

.A study of small quantities of quarternary alloying materials on-transgranular stress .corrosion cracking of Mgli-purity 20$ Cr-20?£ Niaustenitic stainless steel has been made. Of particular effectivenessin promoting stress corrosion is Mo with a aax. ef£ec.t...at a cpncn. offsjl.&fo, lit hu,s a oinilar hxii lesa narke' t'ffcct. "on•• the .other handthe addn. of 20^ Ou markedly diminishes cracking susceptibiiity. .It is thought that Mo will reduce diffusion rates white Ou willenhance diffusion rates and promote rapid reprding at ¡strews corrosionsites. The addn. of Ci some what" ffOun"¿eracts"rthVcrack"inducing .tendency-of Mo. Ultrapure alloys were induction-melted, in magnesiacrucibles in a He atm. More impure C-bearing compans. were arc-melted.Samples were rolled into sheets and cut into strips homogenized insealed Vycorcapsules-at ÍÓOO*, and water quenched. They were thenexposed to. boiling MgClg (42^) in the absence of cathodic progectionwhile strained in tension to Zfo extension. Time to complete fracture ,:was recorded. 50 references. : '

I

239, Saxena, M-Nj Mishra, M S . ' • ; ;-;. • . ', ,-.

STRESS CORROSION .CRACKING. ' . . ; ,-••:, ;-,.y

J. Inst. Eng. (India) 4 8 Í 2 , (CHI), 21-28; 1967.', . . V . : .C ,'

Stress corrosion cracking is briefly reyiewly reviewed and crackinitiation and, propagation are discussed in outline. ; iO references!

24

- 86 -

5ELS.

Nieness. of

a

osion

iaelted.nnionture • '

240. Scully, JO"

ELECTROCHEMICAL PARAMETERS Oí1 STRESS CORROSION CRACKING,

Corroa'^'Sci. 8:7, 513-23j 1968.

Detailed considerations is given" to the effect of failure topassiváte at a slip step produced a!t the tip of a transgranular stresscorrosion crack in relation to the effect of selective denudation ofthe protective species in the environment around the step; the speedof slip step formation is assumed const, and the arguments apply-to an alloy with a propagating crack of a certain depth and widthat a fixed temp, and for a given grain size. Aspects discussed indetail include repassivation, ionic strength, anodic polarization,addn. of solute elements, etc.; reference is made to austeniticstainless steels in halide media, to. Ti in Cl~ media, etc.Repassivation considerations can be useful and tunnel corrosion insusceptible alloys is also significant, particularly as regards therole of the anion; in the latter case, solute segregation within theslip plane along which attack proceeds is important. The environmentprovides an active surface by preventing repassivation and by causingfilm breakdown initially. Tunnel corrosion can appear in SO-2" soln.with cathodically charged foils of 18 Gx-Bfo Hi stainless steel, allowedsubsequnetly to repassivate by switching off the charging current;under stress-corrosion conditions, tunnel corrosion will not be foundin SO.2- solns. because repassivation occurs on the emergent steptoo rapidly. Addnl* factors of importance include metallurgicalcondition, local galvanic couples, pptn. of insol. Cl~ salts, cathodicdepolarizers acting- at morenoble potentials than the 0 electrode,plating out of noble cations, etc.; these may all promote crackingin dil. Cl'media which might otherwise be considered safe. In othermedia, these factors may also be deterimental. 38 references.

es.

241. Soully, J C .

THE ROLE OP YIELDING IN STRESS CORROSION CRACKING.

fhys. Basis Yield Itacture, Conf. rtoc, Oxford 119-24; 1966.

Electron metallography shows, that dislocations are preferentiallyattached during the stress-corrosion cracking of 18Cr-8Ni steels andTi alloys., Tliis highoy localized attack is found only on alloys

. susceptible to cracking. On nonsusceptible alloys such attackis random and widesoread. It is characteristic of susceptible alloysthat dislocations form long planar arrays. The main effect of thecorrosive medium is to release this pile-up and the subsequentrapid attack on dislocations moving along a slip plane represents thepfopagation of the stress corrosion cracky

- 67 ~ Contd...

The.role of yielding in producing moving dislocations of suchpronounced chem. reactivity is considered in detail. Yielding in'alloys that do not readily cross slip causes considerable shearstrain which prevents the'formation of a protective film at the tipof a crack, promotes electrochem. reactions by reacting turbulent,conditions near the tip and by.causing segregational effects withinthe alloy lattice, and it may also increase the aggressiveness of thecorrodent through preferential adsorption on newly created slipsteps. 16 references.

244 i

ñH8¡!

242, Shimose, T et .al .

STRESS CORROSION CRACKING OP AUSTEMITIC STAINLESS STEELS. IN CHLORIDESOLUTIONS. . . . , . •

Trans. Japan Inst. Metals 8:2, 83-7; 1965.

An investigation was carried out on the effects of stress, chlorideconcn., temp., and 0 on the stress corrosion cracking behavior of18-8 and 18-13 Mo steels. Tests were made in the autoclave withchloride ion concn.. varying from zero to 300,000 ppm. at Í3O0 to 250°.The susceptibility for stress corrosion cracking increased with the

"• - increase in chloride concn. and (or) teap. The addn, of 0 to the••• autoclave promoted the tendency to stress corrosion cracking, at

180° the Í8-8 steel•cracked at 300 ppm. chloride ion concn. in theliquid phase and at 10 ppm. in the vapor phase. Thes.e results suggestthe presence of definite threshold stresses for the stress corrosion

cracking which depend on the chem. cpapn. and corrosion environments,such as temp., and chloride ion and 0 concns. .In dil. chloride solns.all clacks originated in pits'formed in both the vapor and the

liquid phases. Complete exclusion" of 0 eliminated the occurrenceof "stress corrosion cracking as well as pitting corrosion.

243. Shively, J H et al . .

CREEP UNDER HIGH HEAT PLÜX AND STRESS RUPTURE PROPERTIES OF oAUSTENITIC STAINLESS STEELS IN ELEVATED-TEMPERATURE SODIUM?

ANL-7520 (Pt.l) pp. 74-92. ' , . : . ; .

Í >'

245.

246.

- 88 -

•

244» Shreir, L L , . : •

REVIEW'OF ELECTROCHEMICAL METHODS FOR STUDYING HYDROGEN EMBRITTLEMPNTMSB STRESS CORROSION CRACKING,, (in German)

Werkst. Korros, 21:8, 613^29 ¡j 1970»

Tlié'features common to or different for both the H eiabrittlement;' and stress corrosion cracking, the electrochem. methods for

-studying H embrittlement, the methods for studying the contents andand the states of H in the.metals, and the internal stresses dueto H are reviewed. The.H absorption is regarded as a side reactionaccompanying the overall reaction. Stress corrosion craoking isthe joint action of mech. and chem. processes.

245, Shreir, L L • - • : - , . .

. . REVIEW OF ELECTROCHEMICAL METHODS OF STUDYING HYDROGEN EKBRITILEMENTAFD STRESS CORROSION CRACKING., (in. German) • ..•••< '

Werkstoffe u. Korrosiqn, 21:8, 613-29? 1970.

Apparatus and methods for tlie study of these processes are described»The similar and dissimilar features of. the two types, of failure arediscussed. H absorption can be regarded as, a side reaction, thereaction conditions and the structure of the metal are the mainfactors. Methods for investigating the' amounts and state of H: andinternal stresses which are developed are, reviewed.. Stress corrosioncracking results from a combination of" chemical and mechanical""

' processes in the case. of. martens'it ic steels» 73 re-ferences»-

246« Shustova, Z F • et ai ' '• ,. • . .'" . . -.-•-.

• TENDENCY OF HIGH STRENGTH CHROMIUM NICKEL STAINLESS STEEL 1HM6N4B;(E? 56) .(Wéíds) TOWARDS CORROSION CRACKING.. (in Russian)

Zashchita Metallov, 6:6 636-700; .1970. ;. '"•• . •=• •

The tendency of welds in high-strength Cr-JJi steel lKlil6N4B to-suffercorrosion cracking was studied in relation to the form of heattreatment applied and the other mechanical characteristics of theoriginal material. Welds in samples tempered at 300-600°C

.'• (UTS'tOO kg/mm2) suffered no stress corrosion. Welds in samplestempered at lower temp, or not tempered at all (UTS 120 kg/mm*)suffered severe stress corrosion although this effect was reducedon heat-treating at 600°C.

-89 -

2!

247. Shuvalox, 7 A étol ' .

• EFFECT OP THE SURFACE TREATMENT OF AUSTENITIC STAINLESS STEEL "Khl81J10T ON-ITS RESISTANCE TO CORROSION .CRACKING., (in Russian)

•;_,-.,;; Khim.,./Mekhan. Mat. 5:i, 123-124} 1969. . ' .

The effect of surface treatment (shot or sand blasting) on theresistance of austenitic stainless steel Khi8N10T to corrosion-cracking in a boiling solution of MgClg-FeClg was studied. Surface

• treatment increased the corrosioh-craeicing resistance of all samples,whether in the stressed state or otherwáe; fche best effect wasobtained by ueing a jet of fine sand (grain size 0.01-0.1 mm).Subsequent working of • the samples tended to re.duce this beneficial¡effect.; 8 references*- • _ ,

-1 !•

248. Shuvalov, V A et'al

EFFECT OF THE SURFACE TREATMENT OF AUSTENITIC STAINLESS STEELKM8N10T OH ITS .RESISTANCE TO STRESS CORROSION CROCKING, (in Russian)

Fiz.-IQiim. Mekh. llater. 5:1, 123-4j 1969.

Austenitic steel type 18-8 is widely used but under certain conditionsit.suffers from corrosion cracking.- A study was made'of the effect

,:. . ; :of surf ace treatment of this steel on its, resistance to corrosion• ' . crackingi as the quality of surface finish improves the rate, of

corrosion decreasses. both for preliminary' cold formed and stressedspecimens. Best result's were obtained with fine aand (0.015-0.15).

, Deformation of the sand»blasted metal sharply reduces the corrosioncracking resistance which is attributed to disturbance of the processcontinuity. The film obtained during heat treatment (stabilizingannealing at 870° for 3 hrs.) of steel 18-8 has a marked effect on theresistance. Data shown indicate that films developed .on these steelswhen stabilizing in* any of the media investigated, "except air,*: .' • ;increase the time before cracking. : •

249. simvaloy, V Aj Gerasimov, V V

STRESS CORROSION OF STAINLESS STEELS IN. AERATED STEM.'

; Sov. Mater, Sci., 4:2, 118=20? 1068i " ' ....

- 90

250. . Shvarts , G L; Akshentseva, A P

• EFFECT OF HEAT TREATMENT ON THE RESISTAITCE TO CORROSION CRACKING OFPIPES MADE OF STEEL, lKhl8N12M2T. ;. • . . .

Tr. Vses.. Naúchn.-Issled» i. Kons.trukt» I n s t . Shim. Mastiinostr. 37 ,-;••• ;: ' 2 9 - 5 4 ? 1 9 6 1 ; ; ; / . . ; • ; ' . • ' .-."," ' . . '/{" : > .;•.-.. • • . ¿ " J " , . .

) " '' '

Seamless, and "welded pipes of s/fcainles.s s t e e l s ,1KM8N9T and' whicii '"¿re sTiijject to considerable t e n s i l e s t resses i n use» are very

suscept ib le .to corrosion,.craclcing-in chloride sp ins . In a lk . media- (cbnce. %C!H^ t]i"ej;.are I'ess susceptible^, ' Cracking i s t r ansc rys t

' ; •S-taibilizing'-.'.ánnjbpliiig .of seaaless iKhÍ8N9T-and. Hil8íílSiÍ2T pipes•and; welded; Í.E1Í8N&T' pipes. at.920f fpr;.Jk. 2 ; hr s¿ : followed'by cooling/-•in the a i r preyfeiits c'orr;osipn.cracking i a 42^ MgClg and coned.

ííaOH a t 2Qp**'''ilsfeVof pipes made of,,these 3t.eel3 ir. chloride so lns .. i s ! h ó i recQiunended s ince , "after a s t a b i l i z i n g anneal, theyf-are subjectJ1 " to l considerable Ipbajqórros4.ón and .corrosion¡cracking ' in these soliis

soineit ^.Stabilizing Annealing" a t -,..920° and quenching of'seamless"Apipes óf ti i 'ese"steels ,4.3 recommended..for.most corrosive media* esp ."•-'•media-causing corrosion^ cracking of s t ressed metal . From Ref. Zli.,

Éhim. Abstr. iip,:6K20.;;l9e3,/: ' ". ;.•-....

251V Shyarts, et al"

THE INFLUENCE OF THE CHEMICAL COMPOSITION AM) STRUCTURE OF STAINLESSSTEELS ON THEIR CORROSION RESISTANCE IN AGGRESSIVE iffi'DIA. . ;

Proc. Third Internal» Congress on.'Metallic Corrosion, Moscow, 1966,23Í-24J5 r ^ : :!

Studies of the conditions leading.to intercxystal l ine s t ruc tura l -eolewtiye .corrosión and,corrosion crackin^ of aus teni t ic , áus ten i t ic -f e r r i t i c» aiid: austenit ic-marteneit io s ta inless s t ee l s , are discussed

with'-ref. to these corrosion modes. All ^lisee ^ p e s of s tee l are .susceptible to in%er crystal l ine corrosion unde.r certain 'condit ions!the fér í i t ic" s ta in less s tee ls are most subject to s t ructural select ivecorrosion and are a l so susceptible to corrosión crocking ; Examples ofcorrosion ofácking of •íii¿h-alioy Cr-Ni steel in H2S0¿í8Clu*ions "

are reported i 10 rerer enees* „ . . . • ' : ,

i,.'- ! 'f'•' -

C '" I "-•

- 91 -

C ' / * . . , - " . " . ••

' • ' . - ' • " - ' • ' . * ( '

252. S i i v a r t s , G L < e t a . l . - • ; • !' '---. '/•••'• :\'- ' . , ' . : . / " < : \ ; ~ « - ' i .

'EFFECTS OF THE CHEMICAL £?ÓMÍOSÍTÍ(jN" AND STROCTÚRÉ7OF;STMNLESSSTEELS QN .THEIR CORROSÍON RESISTANCE IN AGRESSIV1 Jffipi£*.. ' ( i n Russian)

TrVMezhdunar* Korroz. Metal.', 1 , 23&f43j

.253."

,; !Ehe interc^rystit.and..structüré^électívé••\co£f.qsl'p;n^&e well-as thepbrrosion cracks of: a u s t e n i t i c , 'ausjtenitticêrrit-JLá, and; ;auateni t ic -

; teaterisitip .stéeil.a aré. discussed.*' Austefiiîpr£e.rri it,ic:'St,e^ a re most; ,pfterVaf'f"feot'edlby, the struPture*¿éleotiyé^¿prrpsÍ9n^.^ to

í l i terature data! the córrós iV-e cracking <j " aüstén%|iQ-i-f'erritic steel

•::i'ñ;"tne presence lof stresses cprrospohdiiígîp;botii)íiie-'elastic andplastpLo defoimationi MetallPgra^hlii; sf'tu -ies • r"eveaiediUti5at: the•f A'tji OÍ11*AB ' T*nT1 ' Ttcf'UrCk fifi *t*1i A ' C 11 tt *(*£• Vt*i 'i~ &"* tíYíft "f*¿T*í*í T O ^YÔ-I M Q £10'' WP I 1 AS

-.through',them.:- •-Aust6nític-mai iténslstic : sjbeéis. a re .nior,e,ci?§ck-resistaht..; ' .-In KHI.SNIOT^steel 'tlieVpradfea"'appear"-:aft.¿¿; iOOr-SOO h r s .of t e s t i ng in 42?e MgClg» while i n ^Í5.N^yu s t e e l , the cracks do notappear, 'even af te r 40t0o h r s . of te'stinig".:. The;resistance \oi Cr-His t ee l s corrosion cracking ihcrea-ses witli injcréasé of .^he ,Nt cpntenti n the s t e e l . In,42$ MgClg a t 142°, the cracks fonaed i n '•*"0Kh23N28M33)3T stee'l only af ter 2250, h r s . ., , .' i;;».,,-'-;';.;. ¿\i<. «• •- ;

Sidorov,.. V Pj Ryabchenkov, A V- .':'"•''K .,': ,v.;''--:'.:;--j •''"-'•?-'..•'->'

EFFECT OF CERTAIN FACTORS ON CORROSIONBOILER STEELS. " -/'J. '..' •:' . : ' -,

Tsentr . Nauchu-Issl^d. Ihg-tí. .Tékhnol.,. i; í5a3liinpVte;,.92-j 1959..

STRESS OORROSIOF CRACKING- OF :fiIGHATMOSPHERIC, -ENTIRÓNMENfS» V[r< ^'-'^

,»•.

ST,RpGTE "STAINLESS ^STEELS;-IN

.AD-266,005, 38p.:.

The stainless s teels |nclude the cpldrrolled austenitics (USS 12 MoV),the martensitio ¿rade^ (l7-4pH and stainless W), the martehsitic" pptn*

,j hardenable grades (l7-|4pH, pH.Í5-f Mb, AM 350 and 355), atíd the.•/•j semiaústenitic. pptni-Wardenable grades (AIS! 301,. 201, ,an4 202, TJSS\ Tenelpn, and USS.<i?-5)\ Ezppsurfct' were- in. the .marine atm, at KureI Beach, outdoors | t several semi-industrial locations, and in severalít, lab. test environment andunéch. properties pf the test materials^

• Vare, included.; . • ' -1

255* Smialpwski,/ M '• ' i ' • ^ • ' • - • • - ' ' • . . ' - : y : - ' • " • 5 - - ' " : ' l • ' • .,•••. • : ' . . . . • • - . . . . ' > •

STRESS CORROSÍON OF - ATJSTMlfeC QHEOMIUM-HICKEL .STEELS, ( i n P o l i s h )

clíré;• Karcz;,, 12.: 7, 145-8.; 1969.

Întergrantflar'atresS oof:rosioncracking of austenitic Gr-Ni steels is!dés"c;r£;b'ed,• "and '"effect' of 'the 'stetel jcpmpn» and structure, surfaceprépnyy-s&iñ._,';:cóiípn*y-eiectasbde potéhtials, ?and stresses on this

[ pS¡én^6.¿útí:;á!íé:;diécuásedi¿:L''-Jlíeohan±-sm1'of;'"tli'e cracking is outlined-.1 1 2 • 1 r e í f ! é r é r i & ' e s v i : - o ' : ' 1 ' - ' •• '': ' ' ' ' '-'•'"'" ' : " " ' ' .

'256v Smxa¿r H H v ' , e t a l ; • ••-'••• ]• '![ ••;•-.. ; "_ _ ' I , . " '

STWX OF'..STRESS CSORROSIGS" CRACKING BÍ' WEDGErPORCE EOALING.

£ « . E ^ a c t u r e Mec la . , i , • i 2 3 - ; 8 ' j ' 1 9 6 8 . .

25?,.

HÍCR0TÓî;O'GYÓP.:!STRESS' CORROSi.QN CRACKING (OP- IRON-NICKEL-CHROMIÜM

' filmÉ-wér^ éiafflihed'-.ih the electron' microscopebef'bre- ánd?af.tér exposure • t'ó'-boiíipé ?^CÍ«. '•' Alloy ¿óíñpn» ;were

• Fe*tefa$i~20iCjfi #e±i3j(>>:m~20fo CJr-1.5^; SÍ> F¿-Í5^"'ííi-20?5 Qr-0,1^ N, ¿^d-:;Pe¿y^r-Nir2(^'';Cr--"(állya^;:--^).;r;'EÍabfi; alloy was. treated to obtains^rdcturee- in^the 'átinéáléd, •fetraiiied- and aged"condition'» .Examination

[óf j;spécii?ieqíS•;expoéed^to'7BpiHñg íígClp shpwbd .that stress exerts ah;,important; iiiíltíeiicé-bh ^ the BOSÉ .o ' crücking. 'j In ihe absencie ,6Ístress, , attack tended- to take tke íform of pitting. With stress, théattack was highiy -oriented with tlie" pitting aligned in parallelcrystallographic directions. '• Tbe'.'^lloy conrg.. P eadiibited pitt ing ..with definite geonetric. shape;s., • Défec%:"str\ictüre in' the tliiii filmappeared to ha-ê; l i t t l e córrelatiqá îth established .^trends in .-> tí,cracking suicéptibíli-Éy •OΓ with th4 npde'-.o'í dis soln. of. thiii films.1 4 r e f e r e n c e s . , , . ''•: •;',..:' •• \' ""'•' ' ; | y ' ; . •••>•••• } • • " • ' y ' V - • ' ' ; " ; ~ ' V " • "'•'• ••'''• \

r'-. Si, '- "

2513* • Smith, ; T Jf Steehle, E ff . • '

MICEOTOBQItOGY OF STRESS CORROSION ¿RACKING, (in Russian) v ,

••'•'-,"'ir. Mezhdiinar.Xongr. Kofroz, Metal», 2, 809-18» Í966.

Thin filma of austeni t ic s t ee l s ;coníg¿ in' at." $ Fe+15 + 2(5 Cr¿Ée +/15NÍ+ l , 5 . S i , Fe +15 Ni ,+ 20 Cr +-0.1 P, ¡andvFe +j45 Ni;.+ 20 Or

. were éiámd* by /electrón microscopy», ,*The. samples were, subjected to,: : yîbus, . tréátóénts i añneále.d at' 1090°. for 2 /miftr;} • annéale.d .añd 5$. .

' 'stíái^é.d^'atóieaíed., ..strained, and aged'.'at-¿8?Q°¿ during 1 li¿, .fallowingV microscopîc'Observations, the samples "were exposed to corrosión inV'. conventional boiling 42$ MgClg solris. , -and reexaíad.' 23íe'structure

of a l l al loys.contg. 15?S Ni was similar, regardless of the presenceor absence of P and S i . Tlie micrographs of the alloys; afte.r./'anneal'ing,s t ra in ing, aging, and corrosion test ing are juxtaposed- Stressa l t e r s the dissoln. pat tern: random p i t t i ng i s transformed to highlyoriented arrays. Hilé presence or absence of dislocations owing todifferent pretreatments affects dissoln.. only slig;hMy. Dissoln. . .a c t i v i t y of the P contg. alloy.was much iaore-intense, whereas a l lother s tee ls corroded more or. less in a similar way1. The possiblemeclianism of sti?es.s-corrosion cracking i s considered in view of the 'expti*,evidences. Evidence for a Bond-type mechanism requiring the

\ propagation of .cracks in.,a strained.metal through al ternat ing'.-:.."•'•' embrittíemeñt and destruction effects rather, poor. .No! similar;

• -patterns'were..observed./ ¿.mechanism involving passive film breakdown,followed by rapid metal dissoln. explains bet ter the exp,t|..i>.faots and

.. i s in agreement with previous concepts. ' The HVmechanism' may be.: applicable,, but expt l . -eyidence i s s t i l l , inadetuate. .;?;Thé-6.orr'osion

:' y5áttj^.;i|7ÍA-aS?eaaent'- ;with.a>. tunnel modeicwhich;f presumes'.that ... ..tjft'éjliighíy'oriented arrays- of,';pits, coírêspond ftp.'î¿parl"y::aitüáted '

*- : ;'. turin'eisi.t'/vTñe" prigin and -propagation ,mechánism":;pf thesê- tunnels -is;, not yet , clacified». dislocations,;howeverj; ate not responsible^..and

• ' ' ';; the existence o^ aii Unknown digsplni^procesfii ,is/ presum.ed»../r¿leptrochea. .^Ór i t e r i aô f f e r a^better.¡explanation- of ;stresq-,corrosion.c'âckiág than

...'. a s^áck: tf ault approach, ' j - . ,."- i '.'.•--,'*.<= '.,:•, ,-.••'•'.' l-.\í.-^\ ...

260. S1

261, St

259'.-v

PATIGfI]Ey.'/(In. German)v>. .

ifferkst. KorroB. 20i9 , 73Í-49| 1969. ., / ; ? v .', -•.;:"'

Stress corrosiónvexpt's» were carr ied put on»the NTb stabil izedauBtenitip erteel X Í0 CririKb Igt 9, pa. .var|oua concns. oí!SgClgat; various tempsv w^tli externally. app3Tie|,'current,a t the "rube" poteüVia?l=iíl>y anodic, polaOrissation, and mech..; t ie ts° suchas expansion measurements^ creep, curvea, añd.metallpgtáphicinvest igat ions. Tránscrysf. s t r ess corrosion cracking in•. chloride

' •-.,-. ' ' .'c--?j. ; ;. l};-¡-'.¿ ~ 9 4 "" --,;».... °,.'--- .. '"-,• .- '; Contdi.y». •"

í»

,solna. Í B a more "unequal, weak, localized kind of corrosion ascompared with the transcryst. fatigué corrosion of the same steel underpassifying action in chloride-free reducing action. In fatiguecorrosion, in a.wMe: range of exptl. conditions, only a single crackoocurs» at the place,where syclic stresses cause slip of sufficientheight to break -through the surface. The mechanism of stress corrosioncracking,in,the range of'and"above the Q,2?S elastic limit differs in

,.,s: the occurrence of spreading slip plane slipage, with increasing,\ .difficulty, in restoring the passive slip by a redox reaction*'"C9i~lbrj.de.,,ions;penetrate to the slip plane, making repassivation of the^surfaces even more difficult; These di'plac ementa" lead .to nearly slip

, plane /displacement; and 'the formation of submicroscppic notches, which"'finally, reach macroscopic size. Pits are formed, and oracksradiate from the surface of the pit. These displacements do not oocurwhen "the stresses are clearly under the 0,2$ elastic limit orwhen the austenitic steel is cold hardened.

260. Stáéhlé, R V

•' CIRCUMTIIÍG, AUTOCLAVE "SYSTEM POP. STRESS CORROSION CRACKING STUDIES.

Ai?ér,. Soc. ,Test . . ,Matér¿, Spéci 'Techi í u b l i 425, 248-73; 1966.

A .c i rcúi%ting¡autoclavo system was cons t ruc ted and operated inwhich t ime t o .b reak ing \can be déíd*. exac t ly áü &> 700°F. , p ressure.«S^SOOO p s i » i :a;wide range •••óf; s t r e s s e s ¿"' v a r i o u s cpncns. of .dls 'spived gases .and . ionic spééie 's , and fo r a l a rge n o . of speoimensβ ^ p s e d s imui taneous iy . ' ; Gomv. andv s p e c i a l l y melted Fe-Ni~Cr a l l o y s were

•s.Wdi.eiÍv.í.n-/,préÍiminary ,.éxpts'."'; fesuí-ts' confirmed es t ab l i shedtrjends r^prj.".thle,. effects- ;of enViromaént' 'and a l l o y campn. a t 5€)0°F..;

261 , S t a c h l e , R W

• •COMMENTS ON THEE HISTORY;, ENQINEERING AHD SCIENCE OF STRESS CORROSION' : . . ' , : ; , • • • ;

''.''•/;"i.1.1Bpoc^'.Cónf. Fundam» Aspects of S t ress Coipros. Cracking 3-14 | 1969.

Some jp¿.$hei>^'^irqal^.i(^sué'á:..in ipLé;engineeríúg:<'implications of stress^corrosion oraplfcing included incorporation of stress^ có,rrosion,ídata in

!, ¡ i

I. Í! I

i; í: J

•-••.¡95 -

262, S t a e h l e , R W . !

E F F E C T S O F F A B R I C A T I O N , AND,-PROCESSING; ON S T R E S S ; CORROSION ' ¡ O R A J É Í ! ^01? I R b N - Ñ I C ^ É L - C H R Ó M l t r M ! ALLOYS»; ' : - . » • , ; • . ' " ' . .;•»'•• y ^ 1 : ? ' . ' . ' : ! "J ;:

••'••/ x - : , ; . - . ' -:•• "- - \ : : " ' : ; ] l - 7 ; ' . ' " ' ; ' . ' i - , - . / • . . . • • • • • . - ; " C i v . : ' ••!*.1--'' - . - ' • ' ; f ' J . - ' f i - " " ' " - ' ; J A . V ^ ' ' ' ' ; : > •

'Transí;. íns.t."- Chem.: Eng."'47:7'» Í227-T240 f 1969. • ":'. - ; -(V•"•**'"" ';f^'!v ' ': ' .:-'"•;''' '.' ;:'!1"-',: '•..'.;". :''-^-'^C:vi '¿•.i-v;1.'- -i:: • - : ^ ' : 4 . . ^ i ' r ^ y v ^ :Strega cbrróflibá'cracking of áug;t¿ni;tic;rFe*»Ñí-Cr -allbys.já' revitrevi ewe d

încidence bf; ;f¿iiuré.'' Various, alloy-envirorimént systems;íín. w iich: cracking' oéóurs axe; sunmifírizéd, -.Features .of1 the p%s¡'^nvííoíiment are

^ 'S ^ i ^ i^. Al J^ A - —'- ^> J * J£, JLB ^ * _A T .^ ^> J . .A. u . A*. _ ^TΜ. ^ i r ^ ' U «^^h .3 ^^ w» w « w «^^« r ^^ 4h.' .^ ¿^ "1 «. « n % «1 «« X l t f j . it* JΜ • '

welding

263,.

MONTAGE-OF PROCESSES OPERATING DURING STRESS CORROSION. CRACKING.

Coirosion. 23 :7 , 202-3; Í967. . . •• :.-'-,(-.'',',-V-v/!3T,-

•^:A'""chart' i s ' 'Shown''for''ihé rprocesses' opera t ing i n invirqnment' and': •' ',.,withiii metal. which, are - s ign i f ieatti; -in'-:thé'.;meólianíst'ic"interpretatiai

of s ' t ' rese-cdrrosion cracking. Hiis char t does not show ai- l ; ;;ppss ib le phenomena., . C e r t a i n prqcess. mayíbé;r

rjaore • important "diri'ngi n i t i a t i o n thaiix dur ing ' propagaibipn» ," Thi3í>K¿UE§' should ;in¿i;G¿|e..

-the Questionable bas is for, in te rpre ta t ions- baá"éd on only a' s i h g l e ; - ;:method^;qf"analysts such ¿as . ac t iva t ion energy'p'lot's'^'nücl'eaíión-ând

:'•' grbwtlf,- inctibJation t iês , ; propagation ra tes , , óWervat íbñ bf;-j^tiei.in -tóin f a i l s by 'the: ,'S-iectrori ;micrpscoj>e> or •eiéctroííheínV ,t- - ,. =evaiúaiíichtt; of r e l a t i v e l y l a rge .surface areas ' . '-Several1 pi theseiñethbds must be used- in . concer t . • --'. . : • ; '•''.'• , • '• ;. • • '

264. Stáehle,RW' '' • " ' . *'•;'••', -.:/ '•••/-;" -.••'• ; - , ; . \ : / . ; , / ; ; ; ^

'-••-STEEL IN WE "CHEMICAL INDÍrSTRY: FOURTH'ECSC CONGRESS. , I f ¿"^CÜRREIíT .-•'.;SÍATUS.;ÓF STRESS CORROSION CMCKING OF SINGLE PHASE-IRON-CHROMIUM-NICKEL

A L L O Y S * ;- - ' • • • • • / . ; . ••/•J^- • - • : ' • ' Í ; - ^ ; . . - , i . ' - ' - . - . ^ - i ^ ^ . . . >•-• ' " ' " . • ' • ' ; • • • ' • . .

Stee l Internat ,v, , ;5i2$, ?0-23} 1969,' • ' " • • ' " " ' - • ' • ' " ' ' . ' , ' . ' • • , - . " - • • • " ' " ; • - ' . ' > ! • * . * " . ' " ' ' • . ' • • - • ; - - . , . . . ~ - , • • -

The •bôi|8a.ew£'rjoaje]^tS;]rh^cl¿--aré' pa r t i ca la i iy r ikéíy, ío:^"crttcking^'in 'ife-ftihÜÍ '!alioylá; árJB 4iec/ustsed*:¿ ITKé •-^-í--'--<L~-(--^

of /cracking aré; ;ou'tlin4d including Idts3¿pcationi áieajfrey;,," adsprptíbn-inducédsli t-st isp eniichteeiit, and

a s p e c t s

- 9 6 -

» •

265, Staéhle, R W

STRESS CORROSION CRACKING IN Fe-Ni-Cr ALLOYS.

,.'" ,^_Gebelo.oií.'Teeh,-Rep. No, E69 (Belgian) 9p. 1968.

The áus.tenitic Fe-Ni-Cr alloys are characterized by a high toughness,a stress strain curve with no yi'eld point and very high strength aftercold working. .They are.susceptible to stress currosion cracking, as

shown by a stainless steel bellows exposed to steam containingchloride and 0g in the environment, the pressure of impurities suchas N p, P, Ft elements, C, Si and Al' and the existence of a two-phasestruqture of austenité plus ferrite. Hie essential feature of thestress corrosion mechanism appears to' involve a slip-slip dissolution

mechanism-.

266. Staehle, S I •

A STUDY OP THE MECHANISM OF STHESS CORROSION CRACKING IN THE IRON-NÍCKEL-CHROMIUM ALLOY SYSTEM. (Quar ter ly Report , December 17-, 1964-

'March 16, 1965. )

C00-13Í9-24 (1965).

EL

.'*";

Xβ

267,, Staehle,, E ' l ', . , . •

- ; A STUDY OF THE MECHANISM Oí1 STBESS CORROSION CRACKING IN THE IRON-'. NICKEL-CHROMIDM ALLOY SYSTEM. (Quarter ly Report Maidh 17, 1966-Jurié 16 ,

. , . - 1 9 6 6 ) . . , : ' , • • • - ; . • • ; • • • - • - : - - * . • • " • . . ' . . " . -, . ..-' (- . - • •:.' ,

C O O - 1 3 1 9 - 4 2 . - • - . . . -*.''••'•• . . _ • . . . , . • . . . • • - • - . • • • . : , ; ; . • • . . ; . • • •

Stress corrosion cracking experiments ate reported in dilute*chloride. environments at1 506b:F' and in boiling ligClp environments i Data' are

reported in terms of ?¿ unbroken vs time* .Studies show that various: surfaoe^pEeparotions greatly affect mean cracking times and oancause

significant differ enees ?in data seatter. A s tudy of the ••£'£f ect of 'alloys'..-. composition On annealing twin frec[úéncly was completed and final ,

resjllts show generally that increasing the, Ni and Cr increases thefrequency of annealing twins; Results are) reported ffom a study^of tensile .properties as a ftmction of tempera-ture and alloy :

\ composition. A potentiokinetie polarization study was completed foro the ternary !Fe-C*-Ni alloy ^ystém and results aré summarised • w

graphically; Figures préáenting conpepts d?n the, theory of fecorfosion.cracking are ihclttded. = ¿ ,-.\a ,; : . .

- 97 • -

II

2 6 8 . S t a e h l e , R.ff • . • . . • •

• A STUDY OP THE.MECHANISM OP STRESS CORROSION CHACKING IN THE IRON-.BICKEL-CHROMIUM ALLOY SYSTEM. (Quarterly Report Sept. 1?, 1966-Dec.

•16, 1966)

•770.;

271.

COO-1319-53 34p. 1967.

. Reported are results from circulating autoclave studies, opticalmetallography, polarization studies in boiling MgClgi true stresstrue-strain studies, and dynamic straining experiiments conductedin so^tion »t selected potentials. A significant result from thepirculating autoclave studies shows that the cracking rate of..stainless steel below 150°F is greatly reduced.

269. Staehle, B ? ." . •.

A STUDY OP THE MECHANISM OP STRESS CORROSION CRACKING IN THE IRON-NICKEL-CHR0M1UM ALLOY SYSTEM. (Quarterly Report, March 17-June 16,1967.) ; '

272.

COO-1319-57 57p. 1967.

Additional analysis of effects of surface preparation on time-to-cracking in boiling MgCl- shows that the average timé-to-breakingcan be iiireotly correlated with the potential-time behavior as measuredon open circuit. Other analysis of the same data shows that the.data.fit log-normal distribution. Transient,dissolution studiesshow that.the breakdown of passivity by mechanically produced slipsteps does,no,trepassivate nearly as rapidly as chemically (additionof high chibride). broken passivity» Stress-strain studies of nickelsinglé crystals showed that dissolution occurring simultaneouslywith, flow lowers ;the yield point, significantly compared with a flowcurve determined in air. Results of thin foi,l examinatioh containuedto show the/formation of slip step dissolution patterns ,in a widevariety of compoaitibns. An extensive'strain hardening, study-iráacompleted:arid.calculated values for: .the strain'hardening parametersa r e 1 r e p o r t e d ^ . - ' •'' .'-,'•:"'. ^:- ' "•'"'.'. ,,-• "'. ••• ''• ••-," '••:":•' '"' ': • ;, '*'-•/*"-' '• - '•'

A STUDY OP THE MECHANISM OF .STRESS (»RROSION;;CMCKING ;IN THE ;'/:

iROIi^NICKELnCHROMIJJM ALLOY. SYSTEM.. :(Quarterly Report,, June 17,June 17, tóeS-Septémber 16^ 1968). •'""'," •';":• •••:'•

273.

f

£

Cc,t,tV.1c

38p, Í969.

if y

271. Staehle, R

DN--•Dec.

1S3Bdthe

DN-16,

A STUDY. OF THE MECHANISM OF STRESS CORROSION CRACKING IN THE IRON-NICKEL-CHROMIUM ALLOY SYSTEM. (Final Report, June I9'e3-June 1969.

COO-1319-82. 222p. 1970. , • ' ,

272. Staehle, E l . ' • < . -.

A STUDY OF STRESS. CORROSION'CRACKING Iff THE IRGN-IíICKEL-CHROMIÜMALLOY SYSTEM IN CHLORIDE ENVIRONMENTS. (Quarterly Report, Sept. 1¿1969-Nov. 30, 1969.) ' ,

COO-2069-5, 44p* 1970.

Results'-of circulating autoclave teats are reported along withthose from transient dissolution studies, and experiments define: the effects of nitrogen addition on the stress corrosion cracking•behavior» Circulating autoclave autoclave studies were conducted at20p°C in 10 jppM.Cl" + 10 ppM Og. .Specimens failed botfc by localizedpitting, depending on the alloy composition. A review of the literliterature on the subject pf transient.dissolution lies been completedand.is included., The applicability to the present state of theart- is evaluated. Nitrogen additions are shown .to promote theformation of protective film.'. -

leasured

•ip

tionckél

'lowinuede'. ' .

ere

273. Staehle, R W et al .

EFFECT OF ALLOY COMPOSITION; ON STRESS CORROSÍON CRACKING' OF Fl-Cr-Ni: , B A S , E ; , A L L O Y S . • , ; • : . - • •' ' ••--•'••• .••••••'•'• " _ - .- . '

Corrosion, 26: i l , .451-86; 1970. y ,.,:,,' '-,- -

The behavior of Fe-Cr-iii base ¿illoys was studied in boiling MgClg..solutions. The"primary experimental measurements were time-to- Breakiafeof wire specimens, addition, polar izat ion, potential time, currentdecay, constant •potential cracking, and .metallogrixphic studies wereconducted. Alloys with very^.'substantial improvement iri resistance .to; cracking ffere>"foundi.1 The most" effecitiyé,alloy additions were foundto be 'Al / Be aílá-Oí Lowering CΓ to the 10-15$ range was also found to bevery effect . iyeiñ preventing cracking.. The resu l t s are discussedin terms of the s l ip -s tep dissolution model of s t ress corrosioncrackihgi^ 19 references. ,.;.,.. -,'.-''. -,--.;-'.V:'--'11-'. ' : ; •''--'.•;"). ':'''..'• '

•:-.. 1 / ; • • ; - t í f

i ¿- '*• *•'', '

2 ? 4 . S t a e h l e , H W e t a l r . ,

PROCEEDINGS ,0F- CONFERENCE OÍS^ ÍTflp/iMEWTAL^ ASPECTS 0 P : STRESS CORHOSIOlí; V I N G C0L11ÍBÜS, .OBIO,.;SÉPrEMBEá i l - 1 5 , 1 9 6 7 . : . . . . •. , ,

CONF-670985 7 3 6 p . - 1 9 6 9 .

2 7 , 5 . S t a n f o r d , . P .

• ' , - STRESS' CQIÍR0SIO1Í. ( i n D u t c h ) ' "¡'I'. .: . • : ; . ; , ' • ; • " " . ; • , '"f--:

Cons t r u e t i e m a t e r i a l e n , 3 : 1 1 , 1 7 - 2 0 ; 1 9 6 9 . , ' ' . t • .',,

Stress corrosion in-s ta in less s tee ls i s caused by chlorides andthe t i ae - to - fa i lu re of an Fe-Ni-Cr, wire in a boiling'"solution of

. . 4á^JUgCÍÚ••4liü9t-rat"e'e this . ' Tlie. origin-¡of CI ions on:-the surface. .oí; the metal i s discussed and the mechanism of s t ress oorrbsion

•• " cracking, i s . br ief ly outlined. Important parameters are Cl-cpntent,. .. ;, /bemp*;-,-composition of the alióy'.used", pH, etc;."' Hie ' resul ts p f'!',_. .":..;L's,tr,ess, corrosion t e s t s on a number,, of different alloys' including

'."'.. s ta in less s tee ls contgy Ni 8 and 20$.Incploy 800, DS, and"825?• ... . , Hiaonic alloys j and Mdnel '400 are^presen^éd.; Tests'were m^idé'in .' .NaCl .and:Na0H at"300e/C. : Alloys with highfNi content ate' -6he most

': resi.8tan-t.-tq .various types'of corrosion. . -!Hipse. pa r t i cu la r ly : suitable. .;."'are Incoloy ¿00 and 825. . . - . '•:/ - •.

2 7 6 . ' S t a n l e y » / . J K ; . ' • " ' • - , ' ' " ':. .;

SOLUTIP.NS;,TO:SOME STRESS CORROSIOIi CRACKIJJe PROBLEMS ÍH-AEROSPACE• á í T ü A T I O N S . ' ' ' ; .

. Proceedings of the F i r s t jo int Aerospace and Marine Corrosion •• . > .•technology seminar, Los angeles, eal i forniá July 10-12¿1968. .36-43.

F-

M% EFFEdT :OF,HEAT- TRA1TSFER- ON THE CORROSION' B E B A V I O R ' O F TYPE' 304S T A I N L E S S S T E E L I M T B O I L Í M J W A T E R . _ , . . '.;*'••-•_..: ••••.- . • ' '-:'--\ "'• '

" Tra9,s...-Met, SoC AIME, '245 :iq,f2175-!80r 1969..,. •* n:-¡?. '*;- '••''•''•; : ' (

Heat transfer/condi'fcions increase the tendencies of th.e stainléas 'o.steel toward stress corrosión cracking when tlie water_ is" contaminatedwith Cl~ content» Heat treatnent, cliemical cleaning, and degree ofwet film boiling also affect the corrosion of stctinles(3 steels usedas. he.at transfer 'surfaces in Soiling.water. An apparatus for ?

corrosion testing under controlled heat transfer conditions is ' .described. 12 references. •'*•' \ •' ..' -

• " '• " • - 1 0 0 . - / ' •: '. •;••• ' :'"- '• ,'.' ,

" V <J

2 7 8 . S t i e r , H e t a l .

EFFECT OF VARIOUS CONVENE O1JAL HEAT' TREATMENTS OH STRESS CORROSIONRESISTANCE» .

: . AB-293,098, lOp» 1959.

-The stress corrosion resistance of 0.032 and 0.040-in. thick Armeo17-7. pH stainless steel, sheet was eval.uate.dp under a stress of 0.8

. . qf the guaranteed 150,000 ob./in. lain, yiefd strength in the présenosof Federal .Standard Ho. 151A salt 3pray a'tiu. Material conditioned

• ,by EH-1050, TH<-1050, and RH-950 heat treatments and strain¡representative, of fabricating steps were exanxL. Material treated bySH-1050,; TH-1050: and HH*-950'heat treatments possessed stress corrosionsusceptibility inversely related to hardening teup. Doublehardening treatments reduced the stress-corrosion s-uc£pti"bility, butreduced strength below specified values.

279. Streicher, M A

EFFECT OF HEAT TREATMENT ON THE C0ÍLR03I0K OF 16^ AND 25^ CHROMIUM '• STAÍNLESS STEELS.

Conf.. Hat. Ass. Corros.. Eng. Proc. 253-4} 1958...

The present.investigation was undertaken to relate the effect of heattreatment to microstructure, alloy compn. and forns of corrosion by

- using several new evaluation tests, and to det. whether heattreatment also affects corrosion in NaCl and ISigClo solns., with andwithout application of external stress.. Test specimens were, takenfrom 1 com..-heat of AISI 430 (15.85$ 6r) steel and 3 con-heats ofAISI 440 (23-7$ Cr) stainless steels. Heat treatments were made inan el ec. furnace with Aratm.. On Ur-bend specinéns in the soln.-annealed condition there is no intergranular attack on AISI 430 or 446in either the spins. . However, when heated 1 hr at 2200°F and water

. quenched both steels ar.e4subject to stress cracking in both solns.:. ,Ih..the. NaCl soln. cracking is int'ergranular while in, the lágClg soln. .

.it is-primarily transgránular. :The 1st cracks appeared after500.hrs in the NaCl solin. and after ohiy 25 hrs in the MgCÍg soln.

-101 -•

280, Streicher, if A; Sweet, A J

APPARATUS POR STRESS CORROSION TESTS IN BOILING MAGNESIUM CHLORIDES O L U T I O N S . . . " - • "' ; •'•'*''-' '•' '

Corrosion 25s 1,1-6 j 1969.

Time to failure in stress corrosion testa on stainless steels andrelated alloys depends on the temp, of the boiling .iMgClo 'test soln.Small losses of water vapor, and condensate-.from solne. of 40-6 wt..^S.MgClp lead-to .rapid increases,in boiling-temp. , Components of a 3-part•test áppV (flask, condenser^ and .trap) have heén 'designed "to: reduce losses of water vapor and condensate to negligible1 proportions.•With this app. the temp, of the boiling.MgClp soln.- can be held.const, (as 155 ± 1°) fqr 100 day's or. more.., This app'«i can aleo be•r useful for other sblris,~'whose b.ps., ;are significantly'.affected "bystioh losses.- Design details are giyhen.;;for .a 1-1 ¿ modified- Erlemmeyertest'flaskj condenser, and vapor trap*;^Dimensions' are als'O'lf,provided-for 2 stress corrosion specimens,- a Ú-bend and a bfeirfc beam,together with holders for these specimens which fit a 1-liter testapp. • ' •.

281. Subrahaanyam, D V; Staehle, R 77

•STRESS CORROSIÓN CRACKING Al© G1ÉERÁL CORROSIONCHROMIUM, AND THEIR ALLOYS- IN CAUSTIC SOLUTIONS.January 15, 19&9-April'15,. :i969-). ,:•.'.--.:: •

COO-2018-4. 2 Feb. 1970...124p. -• .. ,<¿[.• .,. ;'.': 3/

282. Suss, H"

.;: QF'IRON, NICKEL, '(Quarterly Report,

STRESS CORROSiON Alé HYDROGEN. EraERITiLEMENT PROPERTIES ' OF 17-4 PH IN:• 6 0 0 * Í P . W A T E R S , ' " ^ ' v ' . "'":''"- •'••'•"••"; 1 : • ~ -;"v'••"•'.'/ > • • • • • -•-'••• .

"KAPL-M-6580; . 64p . 1967

Stressed •17-4C'PH. specimens were exposed: for"!700.;days .to" •600°151.3,•••'H-ammoniatéd-HgÓ- and to H-ajnmpniated and '.aerated->HpO- : The .-.susceptibility•• of. the alloy 'aged at 90p°F., to atress corrosion in"60b°F." aerated-,.. HgO was confirmed. No sucli susceptibility' was evident in'sWe -.

H-ammoniatea HgO. .Tli'e susceptibiiityiof the 900°F. aged msíterial to Hembrittlement in both H_0 conditions was shown. This susceptibility,was evident only = with a higli applied stress óf 165>000 pai., forair-melt and 100,000 psi. for consuaable-electrode-melt. materials.- ,No stress corrosion, attack of the alloy, aged at 1025 or 1100eFwin either environment was indicated. The one -failure of each 1025°F

and 1100eF» aged^ with appl-ied stresses^ close to yield strength,basob'een attributed tentatively to H smbrittlement. •'- .'*• _ k/%

- 102 - Contd...

V "-

-part

ns

er

283. Suzuki, i e t a l '

INFLUENCE OP STEEL.COMPOSITION AND CASKET MATERIALS ON THE CREVICECORROSION- OP STAINLES's STEEL PIPING, (in Japanese)

Boshoku Gijutsu (Corros. Eng.)» ^9*3, 17-20} 1970.

The influence of steel composition and insulating gasket materials on, . . the crevice corrosion of stainless steel piping was investigated by

, . loop test and polarization measurements in 5fo NaCl (pH =* 3;0) at50°C» The loop test showed that the crevice corrosion tendency wasmarkedly varied with the composition -of stainless steels and of gasketmaterials- attached tó the steel» Por the stainless' steelcomposition, the tendency decreased in the order: SUS 24, SUS 28, 33and 18 Cr-i6Ni-5Mq, For the gasket material,' it decreased in the orderi

: chryósotileasbestos, blue asbestos, SBR and Teflon. Polarisationmeasurements,.were also made on the stainless steel specimen (crevice»free)land that coupled witla gasket materials (crevice-containing.)•Thé'cúrrént-dénsity ratio-potential'curves showed the same tendencyobtained .from the loop test. -The larger the ratio in the potentialrange from passivation to pitting potential, the larger the crevicecorrosion tendency of the couple of a stainless steel and a gasketmaterial* The variation of the crevice corrosion tendency

, ; '.contributed by the' gasket materials can be explained as being due; . , mainly to the. swelling nature when immersed in +lie environmental

. solution and on the adhesion wetting nature of the surface»

284. Suzuki, T etal ,

'• STRESS CORROSIÓN-CRACKING RESISTANCE OP AUSTEHITIC FEBRITIC. STAINLESS STEELS- WITH HIGH CIRQMITJM AND LOvi NICKEL CONTENTS. '

(in Japanese)

Nippon Kinzoku Gakkai-Si,; 32-11,' 1171-77; Í968.

\ Low-.C, Pe^Cf-Ni;.alloys were studied in order to develop a two-plaase:' stéeí,;-i.c. aüsténitic and férrite, and the resistance tó.stréss-1 corrosipñ tracking.in a" chloride environment was investigated.Marternitic,hardening occurred when the (Cr + Ni)' content y;a.8/

•'/ 'Aé4$'and. the, difference between the. Cr and Ni.contents was ,'>. - Cliariateristic inter granular corrosion of the férri tic steel ; .

could be árrestéd^when the aústenitíc phase was. precipitated t o ^ 10?S.'' 10- references»~ " .'..''.'-• '.'",,• - , •. -' "[ .-.. '. . '. •;. ' •. ' . ..

r

- 103 -

. o "••

285. Takanp, M; Shimodaira, S

ELECTRO® MICROSCOPIC STUDY 01T STRESS CORROSION CRACKING OF AUSTENITICSTAINLESS STEELS, (in Japanese) . . ..

Boshoku Gijutsu 14:5, 206-11; 1965.

Effect of some alloying elements such as C, Ti, Mo, and if ,o,n thesusceptibility of austenitic stainless steels to stress cprrosionclicking was investigated by transmission electrón microscopy with

: tliin-foil specimens of these. Most susceptible of 18-8 stainless• steels was that pohrg. 0.08$ 0* Dislocation arrangements W r edependent on the relative contents of C and Ti,'but addn. of Mo had noeffect. The arrangement of dislocations was planar in !i-con±g.stainless steels, In 18-8, 10-20, and 25-20 stainless steels,

• . N.was.effeeti/ve on stress corrosion susceptibility, In 18-8 and18-20 stainless steels, the dislocation distribution was dependentupon the "relative contents of N and C. Stress corrosion initiatedat slip steps and advanced into the interior of the steel by galvaniccorrosion. '

286. Takano, M; Shimodaira, S • .

MECHANISM FOR THE OCCURRENCE OF STRESS CORROSION CRACKING Iff 18-8AUSTENITIC STAINLESS STEELS, (in Japanese)

Nippon Kinzoku Gakkaishi 29:5, 553-7j 1965.

The effect of N on the stress corrosion cracking susceptibility of18-8 austenitic stainless steels was investigated by transmissionelectron niiscroscopy. It was confirmed from the observations thatthe stress corrosión cracking susceptibility of specimen B wasaugmented. ' These thin' foil specimens were further exatid. afterexposure to.solns. which cause stress.corrosion cracking wasdiscussed. Tlie mechanism, of the stress corrosion cracking ;may beconsidered as follows: Mien the restricted slip planes arecontinuously! exposed to a corrosive environment during plásticdeformation,; the pitting is initiated, at these fresh surfaces. The • .solute atoms1.; are thus segregated to ¡..slip planes with the movingdislocations!;inside the specimen. ' Tliere occurs a high concn.. of solute-atoms on theSslip planes and in their vicinity. The stress corrosioncracking, onee> initiated at the fresli surface, would proceed in the.specimen by an electrochem.'; process. !i. .--?•. .

- 104 -

1

• \ \ •

28?,.i s •Takaho,' M;, Shimoda'ira^' S '• "' • -; -

;i-.,. ' .JffiGHiNISM.OP'STEE3S CC3H0SION CRACKING OP. PACE-CINTERED-CUBIC ALLOYS.• ' . ' ' " " ' : ' \ ' - • ' • • ' " * ^ ' : ; ; - - ' • " : - ; • " " • - • • " •

Sci . Rep^.Res. I n s t . , Tohoku Univ., Ser, A, Suppl. 18, 116-28j 1966.

stress corrosion behavior of austenitic stainless steels, Inconel, ..'.;; and az 70Zn alloy in corrosive environments was'investigated with:thin-foil and bulk specimens.' To study the segregation of solute atoms

. i n austenitic" stainless steels, lastrón tensile tests were carried out/, at'20Ca? and room temp. The mechanism of the. nucleation of ,v• transgránula^ stress corrosioncracking of austenitic stainless, steels,.;in .boiling, 42jSl3gCl2 soln, is different from that of the .propagation*.•'• Mien conditions are satisfied, the tránsgranülar stress corrosion

-cracking proceeds by-,electrochem. reaction alpng the segregated .regions»; The surface film has an important role in the intergranular

. .sibrésé corrosion cracking-of -brass in NH? aq.. solns. Hie initiation..'-•'•'ofti.nidro: pits . (preferential dissolri." at 'tlie fresh slip steps) is not• directly ssocd. with the crack nucleation and its propagation. The-^griáin-boundaries contain dislocations :ánd impurities in high d., and; tthe disturbance increases with'increasing aBsorption of dislocations..under the presence of the surface films, so that the chem. reactionin the grain boundaries becomes moré active, and corrosion is moreaccelerated. 17 references.

'if-

288., Takano, Xs Shimodaira, S. , -

, '- MEGHAITISM FOR THE OCCITEiíEIÍGE OP STHESS CORROSIOET CRACKING IN 18:8.' ATJSTENITIC STAINLESS STEELS, ( i n Japanese)

Nippon Kinzokn.Gakkai-Si, 2 9 : 5 , 553-557} 1965.- ^ ' • ! • • • ' ' = ' • • ' • " • ' • • ' ' ' ' . ' ' " ' " ' ' - ' . • ; . ! ' • ' / ' • ! • ' • ' ' • ' . ; " ' . ' •

',-rJX' Transmission, electron microscopy was used "to study the effect of N• ~ v-on s t ress corrosion,of 18:8 stainless, steels ' . Aplanar arrangement of. : ; J .dislocations occürreqfí-when N:was present',1 the arrangement being

';,••• . 'cellular'•in the .absence of N." With' "specimens" Eohtg.,' N subjected to , .. stress".in boil ing 4zfo JSgCl» solh», p i t t i ng began at. active s l ip •,' v planees .and'advanced'a_long...íhese p lants . Chem. attack ceased i f the

,:. ./''jstrésg-was^reEioyed. In N-freé specimens where; cross-slip,was ;: possible, no pittíng^ooóürred; ,The mechanism of stress corrosion i s

discussed i n terms of thre disipcétion configurations present in the,, -specimen contg, S. 16 references., / ,; , . c

- 105 -

-». ¡ Í -

L ti . in .: rlliá...... j , ,r

289* Takano, Ms Shimodaira, S

• ' STRESS ...COR3OSI OK CHAOJQHG IN AU85M1TIC S.TAIULIdS STEEL UiTOERCONSTANT STRAIN-RATE AED COffSTAM) POLARIZATION.

Trans. Oap. I n s t . Metals 9;4, 294~301s ?96'8»'

"' 'The mechanism cf s t r e s s corrosion cracking of an a u s t e n i t i c s t a in lesss t e e l in 42$ aq.. MgClp solns*, aerated and deaerated," was investigatedunder.'eonsvV.'strain r a t e s and const, po l a r i z a t i on . Prom measurements

," '••' of- the. stre.ss s t r a i n curves and the observation of corrosion behaviors' ' a t slip, s teps produced during s t r e s s corros ion , i t-was found t h a t

' the. suscept ib i l i ty of s t r e s s corrosion t rack ing depended largely.on the dissolved 0 and the oxidizer in a,corrosive medium and on the

v- ; ' polarization, of. specimens, a n d a l s o tha t .the'mechanism of s t r e s s•'•''''" corrosion cfacfeing differed dipending on the s t r a in , ra te3 . The

1 ' 'presence of surface filma on the aus.tenitic stainless- s-teel whichfai led in a i r (elec.tropoiished aurface). and in a éZ'fo.MgC^ aq.

•'sojn,' was confirmad by ,a ref lec t ion electron di f f ract ion íeohnique,and the surface fi, 1ms were found .to consist of varying iaixts. of

' . of Fé-Cr-rlfi 3pinél-typi oxides, or a~ or *Y>P9OOH, and (or) a'FegOg.". ; Tlie corobiñfid act ion of the repassivation of fresh, s l i p steps

produced in the al loy-corrosive system and the ' .s tress to produce• ' •' the corrosion a t par t i cu la r s l i p r-.teps play an ..important role in

s t r e s s corrosion cracking. • ;

290, Takano, M et a l ' • .

A .STUDY OF THE STRESS CORROSION .GRACRIiiG" SUSCEPTIBILITY OF 18-8, STAI1Í1ES8 STEEL BY ELSCTHOii MICROSCOPY< (in Japanese).. .

Mppon Kinzoku ¿ackkaishi 28:5, 2Ü7--44; 1964o

I t i s well known that 18-8 s ta in less s t ee l s are much more susceptible. •tc. s t r e s s corrosion cracking than Inconel. in solnsv contgv 01 ions.

'•• This work was attempted to find out whether' the . .susceptibility tostreds corrosion cracking1 of. these, metals depended on* the kind ofsurface-films bri the' alloys or "on tiie-disl.oca-tion. dis.tribution in

; ' ' 18~8 s ta in less stfeéí wáe also investigated.by transmission electron• . m y s c r b s c o p y , . The surface films formed'on ; 18-8-.stainless s t ee l and

Inconel, which- Were immersed in pure, water or- aq,,;%Ql2.- solution(Cl~, 500 ppm.) ;for 20 hrs.. at 30.0?,, were ^inves^tigated by re la t ionelectron diff ract ion and diffuse r e f l ec t i on , spec t r a . , Hie-films formed"oh both 18-8 s ta in less s t ee l and Inconel consisted on 2Ti (0H)p.

, On the other hand,' there was a remarkable difference in dislocationdistribution/'On these meta ls ; , in 18-8 s ta in less s t e e l , the '"•' .dislocations/vwere confined to Sl ip planes'and stacking fau l t s werepresent, while in Inconel the s l i p was not t r e s t r i c t ed to par t iculardirect ion and cross s l i p easily was allowedi The sufeceptibility tos t ress corrosion cracking of 18-8 s ta in less s tee l i s closely r t l a ted t(stacking faul t energy. The /effect of addnl. elements on the d i s -location d is t r ibu t ion in 18-8 3tainless s teel i s also discussed.

• \ • ' • • - 1 0 6 - .. • : " - ;

Z21. Tariaka, R et a l

53teabsoxs

-.-• VINFLUENCE OF DISSOLVED OXYGEN ON THE STRESS CORROSIÓN BEHAVIOR OP

18Cr-8NÍ AUSTENITIC'STAINLESS STEEL- , ( in Japanese)

Telsú.To Hagane 56:2, 342-50; 1970.In order ,to study the behavior of 0 (dissolved in corrosive agents ) ,

, which hate ,been reported to influence the s t r e s s corrosion cracking ofáus.ténit ic s t a in l e s s s t e e l s , the specimens of the s t e e l were s t ressedand exposed, t o ' 43$ MgCl? soln. or 40$ Fe-Clg so In , under N or a normalátm and the change in d u c t i l i t y and hardness during corrosion, andfrac ture time'were measured. In 42$ MgClg soln, without dissolved 0,the s t r e s s cotfrosion cracking occurred with both the whole immersionspecimen and.-the half i spers ion specimen. -Ihe dissolved 0 i s necessaryfor p i t t i n g . t o occur in high temp» NaCl so ln . , but af ter the i n i t i a lp i t forms, the crack propagation may depend- on H enitrittlemtnt whichr e s u l t s from the nomenOn tha t low pH FeClg' i s formed in the p i t byelectrochem. reac t ion . The s t r e s s corrosion mechanism seems to beexplained from the standpoint of crevice corrosion mechanism, andconsequently i t was not the 0 but. the H that playa an important ro l?in s t r e s s corrosion cracking processes .

Le

aedl

292.- Tanaka, R e t al

INFLUENCE OF HYDROGEN ON STRESS CORROSION BEHAVIOR OF AUSTEiíITÍCSTAINLESS STEEL, ( in Japanese) . .- ' .

Tetsu-tq-Hagane, 55¿:7, 40~*52j 1969.

In order to inves t iga te the behaviors of H embrittlement and s t r e s s• ' corrosion cracking i n aus t en i t i c s t a in l e s s s t e e l , the change in

d u t i l i t y of 18Cr-8Ni s t e e l under various environments was studied:r chief'ly. by means" of 180" r epe t i t i on bending t e s t . The main r e su l t s

obtained a re .as followst the H émbrittlenient in aus t en i t i c s t a in lessV , s tee l , was determined sens i t i ve ly a t the bending t e s t a f t e r pickl ing and

e l e c t r o l y s i s . I t was found t h a t the s tee l also embrittled" durings t r e s s corrosion t e s t i n g in. bo i l ing 42$ ?%CÍ2- solut ion in a. manner

; s imi lar io H erabritiilement by pickling... and eíe.c tro l y s i s . The Hocclusion owing to various environments occurred only risar the surfacelayer» Tlie recovery, of d u c t i l i t y .was l imited a t the i n i t i a t i o nperiod of the embrittlemen-fc and' the longer exposure time made moreembrittlement. I t Was concluded t h a t the H embrittlement plays 'an

. importantr role, i n 1iie formation of the susceptible paths . for theátress corrosion cracking of austenitic stainless steel. 60 references»

- 107 -

•¡•i

293. Tanaka, R} Hsu, T-K .

STAINLESS STEEL 5DR AIíTI-STRÉSS CORHQSION AND HIGH-TEMPERATURE SERVICE.|

Chem. Eeon. Eng. Rev. 217, 18-22; 197a. ' . ,

The s t r e s s corrosion fracture times (hr) in bo i l ing -42$ MgClo so3in.under an applied s t r e s s of 30 kg/mm^, the room-temp, t ens i l e strengths(kg/mm2), elongation ($ ) , 0.2$ proof s t r e s s (Kg/mm2), and rupturetimes (hr) a t 700° under an applied s t r e s s of 15 kg/mm", r e s p . , a r e :new s t a in l e s s s tee l (Cr 17.19, Ni 10.27, C 0.13, Si 0;37, Mn 1.42,V 0.27, Nb 0.35, B 0.02, and (P +S) 0.004-0.25$) J*. 1000¿ 7 Í . 0 ,801, 27 .5 , 900} and com. 304 s t a in l e s s steeL;(Cr 18.49, Ni 8.93,C 0.07, Si 0.74, Mh 1.65, N 0.027, P 0,036, and S O.OIO), / 1 , . . 6 2 . 2 ,80 . Í , ' 21 .1 , 10, re3p. Although' the corrosion of the new s t ee l i n

-•; • 5$ HgS0 4 i s oJ 4-fold greater tlian that of 304 s t e e l , the . i n t e r granular-lcorrosion res is tance, , p i t -cdrfosipn r e s i s t ance , aad-high'rtérip. oxidn.

" ' r e s i s t ance of the new-steel are be t te r than those of 304. Pit-corrosionres i s tance i s esp. good. The cost of the new s t e e l i s possibly onlys l i g h t l y higher than tha t of 304 s t e e l .

294. Tedmon, C S J r . , e t a l " ,. . "

• IBTER5RA1ÍULAR CORROSION OF AUSTMITIC -STAINLESS STEEL.

J . Electrochem. Soc. 118:2, 192-202; 1971.

Tlie wellknown suscept ib i l i ty of sus teni t ic s t a in le s s .steels tointergranular corrosion after heat treatment' a t eeC-BOO0 ( i . e . ,"sensi t izat ion") lias long been a t t r ibuted to depletion of Cr fromregions of the al loy matrix adjacent to grain boundaries i n whichCrggCg had pptd. Those. regijans. of the s tee l in wMcli the localCrcompn. f a l l s below #>^12$ have a"diminished"ability to form, apassive film and hence corrode preferential ly.- Thermodynamic calens. ofof the Cr-C*»Cr23Cg eqjiil. i n and near grain boundaries were made todet . the. Cr content in the v ic in i ty of carbide- particles. ' 'The•"equ.il .Cr content i s ' a strong function of the temp;, and of the C and alloy

•contents, of the* s t e e l . Variations iJi the s i s c e p t i b i l i t y to i n t e r -granular at tack, aré detd. primarily by changes in the' eq.uil. Cr

• content near the carbides and not by changes .in the no. ana. ' ' d i s t r ibu t ion o f"par t i c l e s . Exptl, s tudies of ra tes , of grain boundary

at tack as functions, of temp, and compnw have confirmed, the predictionsof the anal . A further factor of lesis importance i s , the d is t r ibu t ionof carbides i n the:grain boundary, ¿a lcns . were made to det . the Crconén. gradient within, tlié boundary between carbide pa r t i c l e s as a

. function of .temp* and comph. as well as ,the Cr gradient: normal to theboundary. These calóns. predict á strong interdependence betweensusceptibility to intergranular corrosion,: carbide-particle spacing,and séñsitizing temp. » Exptl, result's qn thinned samples of sensitizedmaterial corroded in a Strauss soln. and Esamd. by electron microsoopyare in good agreement wilfc predicted effects. r ;.

<,/•

- 108 '-

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295* Ternes, .. K

• ' ;;'- THE STRESS' CORROSION CRACKING OP IRON ALLOYS, WITH SPECIAL REFERENCE\ m STAINLESS AÜSTEIíIÍIC S.TEELS.

•.••- Werkstoffe Korrosion 14, 729-39; 1963.

The present state of knowledge of stress corrosion cracking ofsteels stainless,ÍH reviewed with emphasis on austenitio steels.

296» Thiruv engadam, - A-, Preiser, H S

CAVITATION DAMAGE II LIQUID METALS.

NASA-CR-72035 79p. 1965.

This report summerizes the results of the investigation on thecavitation damage resistance,- the high frequency fatigue and thestress corrosion "behaviour of five metals in liquid Na up to 1500°F«The test duration is an important parameter in evaluating the

.. relative cavitation damage resistance. Stellite 6B exihibits thegreatest resistance as compared with Cb-132M, T-222, T2M, and 316

\ stainless steel. The rate of damage decreases with increasing temp.~ . High frequency fatigue tests at d^35 ppn. and at «-W100 ppm. oxide

contamination in liquid Ha up to 1500°F. show that the oxide contentdoes not change the fatigue behaviour of TZM and 316- stainlesssteel. The fatifue of 316 stainless steel in 1500eF. ITa at 14000cycles/sec» is comparable with.the results obtained at 1500°F. vocvnn(3 x 10-5 torr) at 4-5. cycles/sec. Ho stress corrosion cracking wasobserved on TZSI and on 316 stainless steel over a 60-hr, test at 2oxide levels (^35 and £4100 ppm.) inliquid Ka at 1000°F. and1500eF. up to 100^ yield.

297. Thomas, E C; Allio, R J

- • . ÜBCHANISM OF STRESS 'CORROSÍOIf 7.8 MATERIALS POR NUCLEAR APPLICATIONS.

... AED-CONF-66-198-16 35p.

298.. Thomas, K C et al

. '•- ' i STR1SS--CORROSION- SUSCEPTIBILITY AHD THE-DISLOCATION ARRANGEIENTS OJPAUSTINITIC- STAINLESS STEELS.. . '

Corrosion Sci. '5:4, 71-9; 1965.

In considering stress corrosion sensitivity in relation to dis- .location arrangements, a study was made of the effee"i~of strainand temp, on dislocation arrangements in type 304^stainless steel

-• 109 r . ; Contd,...

and Incoloy 80S, the former sensitive and the latter..resistant tostress corrosion in MgClg soln. at. 142°. Increased stain for a ~fixed temp, and increased tenip. for a given strain increaseddislocation d. in "both materials; increasing temp,.of Straining hadlittle effect on dislocation arrangement.. Dislocation arrays wereplan-.er, the stacking fault, energy feeing 10 ergs/cm, for. stainlesssteel and 30 ergs/cm.2 CI hr., while Ineolony- 800 did not fail underSimilar conditions in 350 hrs.j the latter effect is attributed to arecording reaction occurring sufficiently quickly to destroy chem.reactive sites need- í for crack initiation. ' 24 references.

299. Tliomas, K C et al

STRESS CORROSION OF TYPE 304 STAINLESS STEEL IN CHLORIDE EMIRONMENTS,

Eorrosion 20:3, 89t-92t; 1963. - . . .

The difference in time to failure of Type 304 stainless steel invarious chloride solution at. cpnt. stress, temp.> -pE value, and Cl"*concn. are dependent. Hie time of failure, increase in the order

•"JJg++, Ca++i Li+. This may be due to adsorption effects which may be. MgClg soln. were made after different surface treatment of the

• stainless steel. Addn. o.f-3.5^ of inhibits' stress corrosion inannealed'or work-hardened steel. Steel jontg. 5.4$ Si resisted thecorrosion for 1000. hrs. . .- . ;

• ' •• ' • - . ' . * ' ' •

300, 'Tiller, F Aj Schrieffer, R . • .

. ' HYDROGM HIMPLE STRESS CORROSION CRACKING.

. Scr.- M e t . 4 : 1 , 5 7 - 6 1 ; 1 9 7 0 . ' . ' - ". • • , ' ' . •..

The characteristics of.stress corrosion cracking is, math, analyzedon'the basis of 2 approxne. for energjr.; Tlie-cal ens. indicate that'electrons flow into regions of highest tension making ;tlie. cracked tipcathodic. .The max.p.d. between the crackled• tip, and bulk metal is

0.8 V. Fluid at the tip of the craek is acids. H"1" chemi-so.rbs onthe metal surface and forms a. covalerut bond. The continuity of -Epumping depends of (i) the discharge of H+ at the metal.surface,(2) the migration rate of H into the metal, (3) the source eoncn.of ff1" ions. '.' .

301. Trt-0'

HYIAU£

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302. Tro

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301. Troiano,. A et al-&*'•••••/•'; , ;

. HYDHÓGM-PERMMBILITY AND STRESS C0RR0SI0F CRACKING IN STABILIZED• " • AUSTENÍTÍIC STEEL.. •

..CEA Symposium on-'Hydrogen in metals', "Valduc, 1967; p. 109-114; 1969.

.By-'electroplating H on one surface of a thin membrane of 310 stainlesssteel ,an4 measuring the rate at which gas escapes from the other side,it was shown that the difusivity of- H is at least 3 orders ofmagnitude lower than ixi Fe, and it is rate determining. In HpS0¿

solution a cathodically applied current is necessary to activate• the surface to allow H to permeate the steel,'but permeation

continues and even increases When the potential is removed. Solutionsof HC1 and NaCl activate the surface spontaneously, corrosion pitsproviding an important means of hydrogenation even under anodicpolarization. H plays a rolé in the nucleaion. and propagation ofcracks in the stress corrosion cracking of f.c.c. austenitic steel.

302. Troiano, A et al

• HYDROGEN INDUCED MBaiTTLÉMENT AND INTERNAL FRICTION lit STABILIZEDAUSTENITlC STEEL.

CEA-Symposium on'Hydrogen in metals', Talduc, Sept. 1967; p. 200-205;207-208; 1969¿ - .

Stress corrosion cracking is attributed to stress induced diffusionof H to regions of high triaxial force, where it lowers the cohesivestrength. Only H which is free to diffuse can influence cracking, andit is. thus important.to determine the nature of H-traps which mayreported on type 310 austenitic steel at l?0-270°K to observe theeffects of straining and ageing oh H-trapping and recovery.7 references.

¡edlat'id tip.sonI

303. Trueb, L F .

C0HR0SI02J AND STRESS C0HJÍ03I0Ñ CMCZING OF EXPLOSIVELY SHOCKEDAUSTENITIC STAINLESS STEELS AND,'EXPLOSION-BONDED STAINLESS" STEEL-TO-

' STEEL CLADS. ; ' '• .

Corrosion, 24:11, 355-58; 1968.

Corrosion rates and sensitivities to stress corrosion cracking of tv/otypes of austenitic stainless steel (304 and 310) were investigatedafter explosive shocking between 90 and 540 kbars. In boiling nitricacid as well as in ferric aulfate-sulfuric acid, the intergranular

-ill - Contd.

corrosion of both 304 and 310 stainless steel was only-mildlyaffected by explosive shocking in fully solution-annealed as well asin sensitized material. Explosive shocking at pressures below acritical threshold value did not increase the sensitivity of eithertype of stainless steel to strese corrosion cracking. Cracking dueto shock-induced residual stresses occurred above 200 khars in 304stainless steel and above 300 kbars in 310. 19 references. •

304. Truman, J E

METHODS AVAILABLE FOR AVOIDING STTESS CORROSION CRACKING OF AÜSTENITIC: STAINÍESS STEELS IK POTENTIALLY DANGEROUS ENVIRONMENTS.

I.S.I. Proc. Conf. on Stainless Steels, Birmingham, ^o'ept, 1968)(P117), 101-109; 1969.

.Stress .corrosion cracking of stainless steels is caused by environmentsthat are quite specific, e.g. solutions of halides or of stronglycaustic substences. The effects, of CI concentration," cation species,temp., 0-concentration, and óf the solution pH; the applied stress;

, and the composition- and metallurgical condition of the steel, onchloride and caustic-induced cracking were investigated. Methodsavailable to ensure that stress corrosion cracking does not occur inservice are considered and possible techniques of improving stresscorrosion cracking resistance are discussed.* 9 references.

307. T:

305. Truman, J E; Perry, R

M)TE ON THE EFFECT OF TESTING TEMPERATURE ON THE STRESS CORROSIONCRACKING OF líáRTENSITIC STAINLESS STEELS. ,

. B r i t . Corrosion J.., 1:9, 369-71? 1966. •

For 13$.Or marten-sitic s t a in less s teels b r i t t l e f racture occurred atup to 30GeC due to- the-presence of E although toughness increased >with temp.- ..The -.degree of1 embrittlement decreased with increaseof temp, for a given H'"content.

308. Ti

306. Truman, J E}. Perry, R , . , • . , •_._• :': . .

THE RESISTANCE. TO STRESS CORROSION CRACKING OF SOME Cr-Ni^Fex AUSTENITIC STEELSANB ALLOYS. • • ' .: . „• ." . ' [ • . .

Brit. Corrosion J.. 1:2,- 60-6;, 1965. ' \.; ..

A study was made:of the effect of variations of Ni and Or contentof austenitie. steel (Cr 10-25, Ni 15-45, Mo 0-5, and CuO-4.0?S)

••"- 1 1 2 - Contd...

on i t s suscept ib i l i ty to s t ress corrosion and caustic cracking. Tensile. . t es t s were effected „in. 42$ ••lágCl-• a t 150% in 40$ CuCl at 110°, in 3$,:iraCl a t 250°,at 2000 p s i . , in 10$ HaCl a t 250° at 2OO6 p s i . , in 50$ifaOH a t 300 " a t 200.0 psi.;, in a strong soln. of NaCl in steam a t 300#

. ' a t 1600 p s i . Increasing Ni reduced s t r e s s corrosion crackingsuscept ib i l i ty in a Cl~ environment; some cracking was s t i l l found i n45^ 'M. Cr. had a reduced effect but a s l ight min. may exist at 15-20$in CI*" media. In NaOH, the beneficial effect of Hi was not so strongbut Cr,increases to 20$ were benef ic ia l . Mo and Cu have l i t t l e.influence in a CI" medium. In addn. to res t r ic ted s l ip some otherfactor i s required for cracking to proceed. Significant featuresrequir ing further stuciy include the specific action of differentha l ides , that of temp., the role cf cation species, the "effect ofcorrodent conen.} a l l these suggest a chem. control factor. •34 references.

307., Truman, J E et a l

' TáE NATURE. OF STRESS G0RKDSIOIÍ CRACK INITIATION WITH MáSTENSITE iSTAINLESS STEELS.. • . •

. Br i t , Corrosion J . , 1:9, 360-68j 1966.

For 13$, Cr.Hartensitic (-i-70 tons/ in ) s ta in less s tee l s cracking wnsi n i t i a t e d l a t . a l a t e stage; of exposure (80-90^ of fa i lure time)i r respect ive of t o t a l time to f a i lu re . Explanations based on H

. embrittlement concepts with i n i t i a t i o n as a slower process than eachstage .of propagation are suggested;

308. Truman,, J E et a t • . , - , , - •

'" ." STRESS CORROSIOSf CRACKING OF MARTEÜÍSITIC STAINLESS STEELS.

J . Iron s tee l I n s t . (London) 2:2, 745-565 1964.

Twelve 12-l!3jS Cr sieels.. cóhtg. "0.07-O.325S C'were studied'using .,. • i' 5/8- 1-in-diam.. t e s t piedee loaded by a- simple lever system by wts.

in an opp. of the. á t r^ss-rupture type. One coffipn. wasted'in sheet•form 10,018 i n - t h i ck ) . ' Four t e s t environments wore: 6fa ÑaCl bonfg.

. 0.5^HoAc and; sa td . -with HgS at 60°, cold 3fo NaCl, boil ing Zfo BTaCl,I the polluted industr ia l , atffi. in thé-'est end of Sheffield; Failure •.:J, •-', can ,beíby corrosion along a narrow act ive path-or, becáuae of H . .Í, ; - embrit3;lemen't.-with "higher tempering temps, corrosion in, ¡the more- c\ / imprtantj with lower,"temps.'. H.imbrittlement. i s the.major catiiei ,'-• '•,-'• The. ¿ embrittlemen-t typ;e\qf fa i lu re is^ due .to; local r a p i d / / / ;,i! ; absorption a t the crack t i p father than to general hydro genat i on.

'I'- - 1 1 3 - C o n t S , . . . •,'

Under ,. acid conditions -the'.strength of. the materials is. themajor factor. Steels with max. stress valuee below 70 tons/sq..in-arerelatively, immune to crack-ing.'.(It is.-doubtful whether any -high-6martehaitic stainless steel could be used safely under corrosiveconditions if tempered" between 250 and 650-.. 29 references.

3(59. Tsekovich, K Nj. Gerasimov, 7,7

p p STRESSES AND RESISTANCE OF SOME 'AÜSTENÍTIC STAINLESSSTEELS TO CORROSION -TT-JR}. (in Russian): • •" " ;(. '

Zashch.. Metal. 5s6, .369.

Investigations of 2nd.-order stresses were made on steels: lKhi8N9T,Kh23iT18 (EI-417), 01Ü123Í128M3DZT ÍEI-943), Kh25iI20S2 ( E I - 2 8 3 ) ,Kh20N14S2 (EI~-21l),..and KM38NT (EI-703), after similar plastic defodeformation as, well as on'the mechanism of the deformation and' itsrelation to corrosion cracking. Hesults of x-ray anals,. indicatedthat there is a relation between 2nd-order stress and resistance ofsteel tó corrosion cracking. Higher stress upon similar plasticdeformation corresponds to .lower steel resistance to cracking inboiling 42$ MgClg + bfi EeClgi a<1 •' solns. It is assumed that in theplastic deformation process of steels, susceptible to corrosion

local sections with higher stresses orgináte before thefrqt of the corrosion crack, and are subject to faster dissóln.Studies, pn~ the,-deformation mechsiiism conducted with an electronmicroscope confirmed the results obtained'by x-ray anals. Por steelÍKhÍ8Í39T plastic deformation ±s achieved mainly by. twinning and roughsliding. As., resistance to corrosion cracking increases, elements oftransverse sliding are dbsd. but twinning and, initial sliding prevail.Twinning is seldom' noted with the aost resistant. EI-Í703 steel.Reformation proceeds mainly owing to initial and transverse sliding.

312i : •

Ó10; Tseikovich,. K H ; Gérasimoy, V .7 • . . . .:

SXRESSES OP THE '.SEC02© KIM • ¿SD RESIüTjüíOE-OP AÜSSlalTIO STAINLESSSTEELS TO CORJSOS ION OMCKING. ' • • : .. . ••.:"" ;.

Prot., Meitáls,;5.:6., .574-76?. 19(59V :• ... -' ** ;

313, .

3 1 1 . U h l i g , - : H _ H ? ' . C o o k i ' , i ' ' E ' . W : J r . ' , ; . - :•...• ' .• .•"•.• •,• ' /'•• '•• ',"•••" ,

MECHANISM OP INHlBÍTÍNG STRESS GORHOSlON.. CSACK-ING OP 18-8' STAINLESSSTEEL MgClo"BY ACETaTES-Aim lilTRATES.. :; • •'•• '. •'[ •

J. Electrochem. Sbe. , 116:2, 173-4775 1969.

- 114 - ; Contd...

Modest additions of sodium acetate, nitrate, iodide, or benzoate toM&Clp. test solution, boiling at 130°C, are found to increaseresistance to or inhibit stress corrosion cracking of 18-8 stainlesssteel. : The critical applied potential in J/feClo solution (-0.145V)

.aboye which,«tut not"below, cracking occurs, is shifted in the no>ledirection by extreaneous salt additions. Tvhen the shift exceeds thecorrosion potential for 18-8 in the saiae solution, cracking isapparently inhibited. On the other hand, salt additions, (FeCl,.)which shift;the.corrosion-potential in the noble direction may °indmce'or accelerate stress corrosion cracking. The criticalpotential is interpreted as that value, above which but not below,01" ions 'adsorb' to cause imperfection siltes of plastically deformingmetal in an amount adequate to cause failure (stress sorption cracking).The present data dc not support an electrochemical mechanism of stresscorrosion cracking based on anodic dissolution of metal ions at thetip of a crack, nor the aechanism dependent on continuous crackingof a surface oxide film*

312i ühliBgi H H; Sava, J P •

ORIGIN OF.DELAY TIME IN STRESS CORROSION CRACKING OF AUSTEMITIC(25.J2O .CeROMIUM-NICEEL) STAINLESS STEELS..

(Nat. Assoc. Corrosion Eng.) 2nd Internat..Congress on MetallicCorrosion, New ¥ork, 211-214; 1963-1966.

Stressed specimens of 25:20. Cr-Ni stainless steel were subjectedto boiling MgClo for various times. Oxide or passive films had• little or no; influence on time to.crack initiation or on propagationrate-.... The important: factor is the time for segregation of N andsimilar atoms to lattice defect sites. -The- segregation of N causesageing and produces".crack-sensitive' paths.

!,:•:

313. . Uhlig, H H; Sava..,-.J. P . .

ORIGIN^OF DELAY TIME-IN:STRESS ;CORROSION CRACKING OF ATJSTENITIC• STAINLESS. STEELS. .. .'..-• ." • ' ' •'

Corrosion Sci. 5:4, • 291-9y Stt.:

In a'study of factors affecting .delay .time in-the stresis corrosion. cracking of stainless steel, tests were made on a Type 310 material

(25 Cr, 20;:35i, 0.03 C, and 0,14$ Mo), either cold roiled.or annealed,in ifeClg soln¿ at 154°j; tests, were oade/by an initial immersion for adefinite'period either just short of or greater than the inductiontime necessary,for initial initiation of cracking followed iy.repickling for 5 min. and further SfeClg testing.

i I

- 115 - Contd...

The time to failure depended only on total previous exposure, time ofunstressed specimens at 154°., whether in MgCl* 9? aiz*j cracking timewas riot altered by interrupting the test early or late, followed byrepickling the stressed specimens and re-exposure to MgClp. The dataare inconsistent with any supposed role of an oxide or passive filmin detg. failure segregation at lattice imperfections and the assocd.time-factor at 154°; N appears to be, the ¿significant impurity. A low-N 2Ó0r<-Í9?6 Hi steel showed no quench-aging or- stress-corrosioncracking sensitivity» . - •

.314., uto, Y

STRESS CORROSION CRACKING OF STAINLESS STEELS BY SULFIDES, (in Japanese)

Boshoku Gijutsu 19:3, 117-25} 1S70.

Stress corrosion cracking and methods for its study end preventionare reviewed. 13 references.

31

315« Vasilenko, I I et al

STRESS CORROSION CRACKING OF STAINLESS STEELS Khl7N2 Alii) KliM5M3 IIICHLORIDE SOLUTIONS, (in Russian) ' " '

(Fiz.-Mekh. Instj Vov). 3:3, 286-92; 1967.

Stress corrosion tests were made of ferritic-martensitic steelY&1T&Z and austenitic^marternsitic steel KliÍ7ír5J5 in 3% and, Zfo É&GIspins, at room temp., and at^ the b.ps. ,of the s.olns Klil7ií2;wásquenched and then tempered at 170-650p; Khl71i5iI3 was normalized,cooled to-70°, and then temppjeed at 450° stresses were induced

.. either by tension or by bend.iog. None of the speoimens tested.at'room temp, in 3$ soln» showed any signs of cracking.1 Tests at theb.ps.j either by immersion or spray, showed that Khl7N2 was moreresistent to stress corrosion, cracking, than Klil7N5M3.. Steel Khl7N2tempered at 17Óe and atnJ460 (brittle'range) was sensitive to"crackingi after tempering,at 340°, it resisted cracking. "None of thespecimens tempered at 650° cracked. In general, the results weremarkedly affected by test, variables, such as aeration or áfternatewetr-dry condition» . . , ..• - '-.' • .'• :

- 116 -

i II i-

se)

316. Vaughan, D A et al

RELATIONSHIP BETWEEN HYDROGEN PICK-UP AND SUSCEPTIBLE PATHS IN, STRESS-CORROSION CRICKING OF TYPE 304 (I8i8) STAINLESS STEEL.

Nat. Assoc* Corrosion Eng. 2nd Internat. Congress on Metallic..Corrosion, New York, 216-226? 1963-1966.

The susceptible paths for stress corrosion cracking in 18:8 Cr-Ni,O,0efo C, stainless steel were identified "by electron-microscopeexamination of thin sections before and after exposure in 42$ MgClp».Difference in susceptibility to stress corrosion cracking were

. attributed to the solubility of H in the steel and the extent of . '.diffusion under applied stress. In resistant steels the hydride

. phases precipitate rapidly and prevent diffusion of H to high-tehsiie-stress regionsj in susceptible steels the ppt. does not formimmediately. El^ct¿'on and photomicrographs of the process areincluded.

317. Vaughan, D A et al

-RELATION BETWEEN HYDROGEN PICKUP AND SUSCEPTIBLE PATHS IN STRESS-C0RR0SI0N CRACKING OP TYPE 304 STAINLESS STEEL.

Corrosion 19:9, 315t-326tj 1963.

The susceptible paths for stress-corrosion cracking in types 304stainless steels were identified by electrón-microscopio exam.of this sections before and after exposure to boiling 42$ MgClg.These paths were generated by- the corrosion reaction, esp. thecathodic part. Type 304 stainless steel reacted with H to formhydride phases which were attacked rapidly by the corrosion..environment and would not be detected in the steel after stress-corrosion cracking failure. Diff^rcnoee in susceptibility' of type304 stainless steel were due to the soly. of H in the steel and theextent of diffusion under applied stress. In resistent steels thehydride phases ppt. rapidly and prevent diffusion of E to high-t ensile-stress regions, ahile, in susceptible-at eels the pptn. doesnot occur immediately. H in solids soln. diffuses through theaustenite lattice under an applied load and forms a stress-orentedtransgranular ppt. phase distribution similar to the distribution ofthe cracks in stress corrosion-cracked specinents.

- 117 - ' fIf-

I

1 'i

• • ' . i ,

313. Veingarten, A M et al .

RESISTANCE OP HIGH-STRENGTH DISPERSION-HARDENED. STAINLESS STEELS TOSTRESS .CORROSION CRACKING. (In Russian) •"- ' ' .

Fiz.-Khim. Mekh. Mater. 6;4, 39-44; 1970.

The study on title resistance were carried out with austenifcic-martensitie steels of different grades. As corrosion medium,., a42$ soln. pf MgGlp a synthetic sea water, and sea water from theBlack Sea were used. Testing temps, were 60 and 100°; and the

. : testing time was 100 hr for the 1st 2 mediums and 1000 lir for thesea water. During testing the time to failure in a given mediumwas detd. at stresses of 0.25 and 1.3 of.the ultimate creep point<TT. In addn., the tensile strength was detd. in air, in 42$ MgClg

and in synthetic sea water at 60 and 100",'as well as.after •immersion.in the corrosion media for 100 hr under stress of 1.0-1.2of ($ T. All tested steels showed a tendency to corrosion cracking

. in boiling 42$ MgCl? and the degree of this tendency depended on 'chem. compn., heat treatment conditions, structure, and the levelof applied stresses.

319. Verma, 2 M' et al

GORROSIOK OF COLD BOX EQTJIHffiNT IN AN AMMONIA PLANT-A CASE HISTORY.

Technology 7 :3 , 176-8 ?'• 1970.

A case h i s to ry of corrosion of cold box equipment i n an MEL,, plant isdiscussed. Some s t a i n l e s s s tee l vessels in- the air-sepn.. and N-wash un i t s were found damaged by corros ion.a t several places duringinstallation. It was concluded after investigation that carbidepptn. coupled with corrosive environment esp. chloride from .insulating.materials were'the main factor responsible for causingooirrosioli"failure of the -stainless steel vessels.

321,

322,

320. Waeker, ' G A • ' .:

EFFECTS' OF MARINE ENVIRONMENT ON' HIGH STRENGTH STEELS.

Amer. Soc. Test. Hater.', Spec. Tech. Publ. 445, 66-87? 1969.

General and stress corrosion cracking behavior of several classesof high•strength steels in the marine environments are investigated.Eleven exptl. heats of maraging steel were evaluated for resistance tostress corrosion cracking in sea water. Alloys contg. 12 or .14$ Niwere susceptible to pitting attack and stress corrosion cracking,while 18$ Ni laaraging steels were highly resistant to pitting attack.

- 118 - Contd.. .

Hie corrosion charac ter i s t ics of. 5Ni-Cr-lib-V HY-130 s tee l were alsoinvestigated in sea water» The stress. ' threshold s t ress for H ^ 1 3 0was detd» by using the c r i t e r i a of no fa i lure after 6 months; of-exposure in natural sea water under sustained s t ress in the •;'

.preci'acked canti lever t e s t . A study was made to det . i f long-termcontinuous cathode protection of HY-130 in sea water would lead to"eventual problems assocd. with H embrittlement. Work u t i l ized

. precracked canti lever specimens, which'were precharged with H a tseveral h i g h - c d . levels and then step loaded to Éailure while s t i l lbeing cathodically protected. Cathodic protection tes t s were alsocarr ied out by.using 2~point loaded bent-bean specimens stressedto 9 ( $ o f the Q,2fo yigld strength which were cathodically protectedat 13 and 130 ma. / f t .^ c .ds . for, 1. protection on the low-cycle•corrosion fatigue behavior of HY-130 was also detd. I t wasconcluded that HY-130 s tee l has good resistance to s t ress corrosioncracking in sea water. • HY-130 steel i s insensi t ive to H embrittl^mentwhen cathodically oyerprotected in sea water and tested as ei ther aprecraked canti lever of bent beam specimen. Cathodic ov&rprotectionof: HY-130 s tee l in sea water reduces the low-cycle corrosion-fatigue

* l i f e of the a l loy .a t ' any given reversed pseudoelastic s t ress l eve l .

321. Warrén, E B . ,

SOME PACTS'ABOUT STRESS CORROSION OP AUSTENIEEC STAINLESS STEELS INREACTOR SYSTEMS.

. ..Reactor Mater. 7:1,. 1-13j 1964, .

322. Watanabe, M;_Jfakai, J '.- • " ,

EFFECT OF COLD VTOREIlTG Oil'STRESS'CORROSION CRACKIiiG OF AUSTENITIC ' .• STAINLESS STEELS' AND THEIR '.VELDED JOINTS.

. ' Technol. Jtlép. Osaka Univ., 20:908-931, 99-120; 1970.

Tlie s t ress , corrosion of several austeni t ic s ta in less s tee ls in boi l ing' . =42$ ligQl^;Solution was investigated under, constant load using a , tes t ing

, machiné an whiclV di rec t ;metallographic observations-could be made-• 'I during t e s t ing . The effects of p r io r cold working--in the temp.-

. : range-196to „+ 100°C on the time to f a i l u re , the quantity of , 'martensite, the i n i t i a t i o n time and propagation tine of s t ress corrosioncrack* and the °effeet of heá-fc treatment on the tine to fa i lure , of .cold-worked material were studied. \Hie .effect;of cold working before»v

'and ,after welding on the°s t ress corrosion behaviour of welded^joints was also examined. , 12 references. ;

r

- 119 -

323. Watan'abe', et-ai

., STRESS CORROSION CRÁCÉIKG 'Of1' AU3TENITIC STAINLESS. STEEL 'AND ITS

. WELDED JOIHT. Ü1ÍDER- PULSATING LOAD. I. PROPAGATION TIME .0? BASS.METAL;,tfNDER PULSATING TRAPEZOID LOAD. . (in Japanese). • ' ' "• "

' Yosetsu aakkai-Shi,39í6, 556-64;.. 1970. '" " . . '

In the first stage of the research on. stress corrosion cracking underdynamic-load, the tested material was AÍSI 304,stainless steel and the• corrosion medium was a boiling soln. of.42$ MgClg (b.l54°)i The• app. was a const, tensile loading type, the load iime.and.the no»' load time of which can be changed arbitrarily. .The damp.ge due to

"•• stress corrosion cracking under pulsating trapezoid load is not equalto the accumulated value of static damage. This damage is .not onlyinfluenced by the dynamic effect due to"the pulsating load but alsoby the lenfth of no-load time» The propagation time can be presumedunder the following assumption: the total s.um of the daaages due toload time, no-load timé, and dynamic effect is equal to the damage. under static load. In the case of the ratio of load time to no-load.In the casé of the ratio of load time to no-load.time being const.,

. the crack propagation time is prolonged by the prolongation of theloading period.

324. Watanabe., M et al . . • . -/.

STRESS CORROSION CRACKING OP AUSTENITIC STAINLESS STEELS. IV»INVESTIGATION OP INDUCTION PERIOD BY METHOD OF PREIMMÉR8I0N.(in Japanese) '

Yosetau Gakkaishi 35:6, 649-56? 1967. . : ,

The mechanism of stress corrosion cracking during the .so-called"induction period" be-fore ceacks initiated was studied by. using .the method of preimmersion. During the induction period, thecorrosion potential of the test piece rose more and- more' independentlyof the.load valué, until at last it reached the necessary valué

causing the occurrence óf "micro-pitting" which was believed to be theinitial stage of stress corrosion cracking. . If the necessary value v

of stress was applied at the time, cracks immediately started.' -Thestress is not necessary until the potential of specimen reaches thenecessary' value descrined above. The. maternal was hot attacked by thecorrosion agent and, it became brittle during the Induction .period.. .'The values of the threshold stress for crack initiation and forcrack propagation were obtained arid generally, the latter had a,lowervalue than the former, " ••: --. . --. - ^ . •'.-•''..':••. • "

325.

326,

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atly

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• 32.5». Watanabe,: -M e t a l ' •• • "' ' . - J : • • • • • • • • ' . ' • " " • ' • •

STRESS- CORROSION. C1ÍACEIN& OF AUSTMlTIC STAINLESS STEELS, V. EFFECTP.P. POTENTIAL CHANGE.ON INITIATION AND PROPAGATION OP CRACKING BY'ELECTROLYSIS, (in Japanese) . :

Yosetsu Gakkarishi 36 J7, 729-37¡ 1967.

The relation between corrosion potential and the 30-called "inductionperiod" of austenitic 3tainless,steels subjected to stress corrosioncracking tests under cathodic or anodic electrolysis is discussed.For cathodic electrolysis, the corrosion potential of the test piecewas 'lowered* Consequently, it took a longer time until thecorrosion potential reached the necessary value for.crack initiation.

... . Therefore,,.the induction period was also lengt'iened. When the c.d. ofoathodic electrolysis increased sufficiently, no stress corrosioncrack occurred during the test time. In this case the corrosion. potential did not reach the necessary value for crack initiation.This is the nechanism of preventing stress corrosion cracking bycathaciic electrolysis Next, a cathodic current was applied to therestrained welded plate under stress corrosion test. Cathodicelectrolysis was effective for preventing stress corrosion cracking...The propagation of stress corrosion cracking qan also be controlledby ,the corrosion potential of the test-piece,

326. ttatanabe, M . et al

STRESS CORED SI ON CRACKING OF AUSTMITIC STAINLESS STESLS, VII. EFFECTOP COLD WORKING. 1. (in Japanese)

Toeetsu Gakkarishi 36s9, 1015-23;.1967.

The effects of cold working on the stress corrosion cracking ofaustenitic stainless, steels in the foiling 42$á MgClo soln. were, studied.

. For ,an 18-8 stainless steel which io transformed partially"intoquasi-iaartensite by cold working, both induction period and crackpropagation, time are changed by cold working. Esp. the crackpropagation time ie very much lengthened by heavy cold working.Por other stainless steels, both induction period and crack-'propagation time are hardly changed by cold working. As a result of ,the quasi-marteñsi.té obstructing -the advance of the cracking, thecrack propagation^ time is lengthened arid .this effect-is generallycalled the^"Keying effect..'1 The, electrocliein. potential of a testpiece indicated at-the crack-piece is-cold worked it indicates aslightly lower potential than the orginal test piece, but when thetest piece is cold .worked heavily it indicates a slightly higherpotential'=thah the original one. The slip, bands occurririg ¿t the tineof cold" working are never, attached during the stress corrosión

' applied test load aré gradually attacked during the stress^ corrosiont e s t * •" -, ••, •. • .• " . . '••

i< •

- 121 Contd...

ii

When a slip band occurs, its fault plane has no protective filmeIf this unprotected fault plane appears in the MeCl2

s o l n'» *•*' is

attacked. If it appears in the atia., its área is sudéénly oxidizedand goes into a passive state. The higher the applied stress, thegreater the no. .of cracks which appear on the surface of iestedspecimen* When the test piece is cold worked, this relation is ;.shifted, toward higher stress followed by increasing yield point .*:•••"••

327» Welinsky, I H et al • - ' . . - .

FINAL EVALUATION OF SHIPPINGPORT POWER STATION'S STAINLESS STEELGENERATOR AFTER HIVE YEARS; • ' . ;

High purity water corrosion of metals^ 1-13 j 1968. (Met.'-A., 6908-. 72; 0151). .-.•'_.. : ;. • . ' , ' : .

The steam generators were tubed with type 304 steel*- Leaks developed• in the. IB .unit after only a short period of operation. " The. unit hasnow been subjected to a conplet destructive examination. Describesthe condition of the taiit and reviews the boiler water control used.Widespread cracking was found in- the tubes. The cracks were.intergranular in the sensitixed sections and transgranular in theannealed sections* Although the cracking could be attributed toeither chloride or caustic stress corrosion, the evidence points tocaustic as.the more probable cause. Most of the cracking.apparentlyoccurred during the initial 150 hr of operation when the boilerwater contained free caustic. Seventeen of 31 typical tubes fromthe IB unit showed performstions, Trisodium and monos odiúín .phosphate were used to adjust pH rather than caustic soda? disodiumphosphate was substituted for sodium pyr.ophospate. and phosphateconcentration was increased. 7 references- .. . . : .

328.. Wendelbo, A H '.,r> ... . . .

• POTENTIOSTATIC DETERMINATION OF.STRESS CORROSION SUSCEPTIBILITY IN431 "STAINLESS STEEL. •• .. . ' , . : ' •. >

. Conf. Nat, Ass. Gorros. Eng. Proc. 556-7} 1968. . . "a .

The presence of Or carbides in the martensitio mati•'.% of 431stainless 3teel parts can be .detected, by means of a simple! galvanicnondestructive test procedure, Mie teat is based on the¿largedifference in small anodic current flows, for acceptable andunacceptable parts. The reí ability qf the 4neiiiod was verified by

. salt siSray; -exposure to failure of stressed parts, which had beenpreviously examd.^ by the galvanic teájfc. Initial expts, were done onrapidly and slowly quenched materials as well as on°parts that had

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^ ^ ^ ^ ^ r e l a t i o n s ' , f.br. the.yarious samples jreré, pl>taine.d, ¿yei ^vyoi^tage.'"range of.; rO.3 *to + 0.5 V, by using a s '.."-.'freaking pí>téntioetat# v 9Jhe β^eetrpiyte.was, 0.?» NaOI-. Voltages werei'v'ét erred.ÍQr>-. SC?, ¿using a Ba^dísi KClr-agar salt brine .and a. FÍ , •.éóíxatsT électrQd"é.:/The electrolyte was stirred with a'vibratoragitatoÉ* • Hh'en c^réntr^oltagerdata were plotted, 2 distinctlyaiffer^nt curvee were,,obtained* - The semilog plot of'o.d.ys. appliedvoltage fpri-th|e"properly ^úencHed material exhibíted a very low .

;,c.d¿>. Over a "-restively, ^ ^ d r a i t g e 'óf applied voltage, while theméajsriái having intergrflínuáait Cr carbides 'exhib i ted passivity over.'anextremely narrow voltage; i'ain^ c.d.

.'between, tfiie, 2; curves showed-tliat this could, form-the basis of the 'desired nónáestructiVie

' jbcEANISM OF STRESS ..(JPfiKOSION CfiACKI G*; ..v ; " ' V ' ' ; • : ' ' • • ' • • = ' ' - " ; - r 5 - ; " ' " - • " • " '

330»

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•i ;•••; CJoÍQfiiid.erati?9|i of t.the data póstrese-corrosión cracking- iñ specific •;- B^stai; s-agge^tá ; ttiá-it rbó,th metal-deformation and ionic solvation

' *. should-b/e ¡considered. /The metal structure may also be' involved, inH ./so far as th.e/electronic conflgtiratioñ oi1 both tlie metal and'its ,' / j sp lya ted ctatipn; may. effect ; the activation energy of the solvation: ;;'-•- process;* : The ;atPms in furface steps haye a very low coordination, ' and áíasólyej/f pllówiiig frpia; y i e l d i n g , / . Ú. . .

STRESS '-"<

- J* • Slieffleid- ^ni¥. MétVSotí.-4:/.27-31^ 1965. " • , ;*í••' •• ? ; • ' • . " X • • / ^ • • ^ • - • / ' j ' : v í / ^ - ' • • . • V " • " - : ^ ' 1 " ^ ' '•-•'- ' - ' • ' ^ • • • • * ' \ - C - ~ ' " ' " ' ' • ' ' ' > ' ' . . ' • - ' ' • ' - " ' " . ' •'-

',. The' •β-trjess -corrosion -crackingJbfo-Jlight'alleys»,'caústió cracking of/ ./nüKfd' ete^l t -seasonal oracMag." ár hráss, ^ d : ch-lpfa de cráckiitg of' ; austenitic steels 'aire féViéwédv 3# references.. - • ' '

CRACfe IN^ AUSTHilTlC STAINLESS .STEEL-..

©racking 4.h stress corrosiphoóf Or 18,' etesl in 4£& lfe01« a t0 ;ot: • "

,3Sfo óíiscdntinwitiee 'were; found'ôp^ti'nxions./^c^ffcbÂ-y.p.rt^pá^

ói á, dynamic,.and eíebtrbchesi.. dissoln., Í.;A jierievj-aE~: *íien

332 * Westwobd,: A

l i W r e l a ^ q n ^ . ^ ;:-

tp; 1.5á3cv10^ r?". dosage %a shpw îafcwtutóéliing!! :*cán;íbe : éxtféáiely , „: deleterious in / te rns of meph.^propertie^s of ifiotoh-brittle":-i--*:?{>-,. •mater ia ls ; r8ifrearib acid Tras used "at'tjie »tép ;poi>orf in th'i"Step-?,p6isbns capable of changing diásbla» -'jficbjo."gejieral"""far1''w i l l probably .be- ,signifi6an,t, i n the ftiteréidevel^paent pj£H'-s!treng|h> but notch \brl :ttle ;v jc-atepiala 'üsfd'.vstrúVtiIBÍfépt-Van,.b!e.reduced I***• ' "+ * «e- - ^ •»»»•»"h-i+>.'~- i««oS;-treng-pi> but notch \brittre ;v jc-atepiala ;us«|d5.v8trúo't«rálly»" íhiS. a';;".iBffiso,t "Can ble/reducéd 'by '«11) .us*e'"ojlr 3>*nhi'bitior*fxons ^Wuich^screen* o^ ^breakdown trbúbiespae poTaptexrspeoíe/s'^théí-.boippn.. of'r-th'é-.splS.d»- ..l&FéfSrMU>é&,1 •:•;•-'-.'¿¡K^'^'.. V.'-.-.-'•:/'•.. :-r:.V; -:J

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334#t M i d e ,4 '•WECmfldtiB FOR. STUDYING OBB KINETICS.OF,IMmGRAlTOLAB CRACK TOC'¡Oír AISI ¡TYPE '304.STálSIJBSSSTEEL IN, eXYGEBTÁOÜSD WÁTERAÍP 289-C.

''iCorreeiok, 25* 359-65/ Í969¿

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S 4 í l 2 , 393-402» Í968;

of Si and Mg pn,thé electróchéiñ. and ¿prrosipn behayipr of;

; a hi¿b>purity austenit ic o14Op/l4 Ñi, báíanCe.Fe, alloy haá beén^"•1-í-'-k' áf. v O .ér iáí£~:5ompn> range 50.41-500 ppm. Sij:%iio effect was •<•"-,_

^d'-ipai t h í lE4.neticas* óf the anodic, pr.; oathodídj par t i a l processes'. •of ilg- over iáie J^ánge. 5.26-30Ó ppm,;ácoelerat"ed the.anodic

diséóln. kinetics- in the áátiye range of 'potentials and.also the ;-,) '/.-"• \stêady—state'corrosion r&te—iii. íí- HrtSO -'w-owii* tovits- inf lüence" •-- v'" \-

• o n -jOk j s o f the cathQdi^ "par'tial proeles s> V^ ie nature of th is ;jras anályaed.'Caccording td electrode ^ ine t i c concepts which- '\7tháti'Mg chkngea vaUue^ of ^lie eieGts:pa.e ^ process transmission

AlliOys. eontg»i l(g; and Si pêr large; boncn. ranges.,are >, "ily^ resistant,^ to stre 'sscorrosic 'n cracking:-'"i n /bailing 42: wt. f? ,

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'^^¿'<í<m%x<^'BÍiaílav..^îíx^;_wmb{^xie\irífh steel Khl8NiOT: (after' \auatenitization./at. 1050?)-:j. The' ehem». compna.,, of' these steels wereîveift»""-the testing foru-corrosion .cracking was,: done' with "ring - .-','"•SpeciiSene having a cross section 2*5,x S^mai,-whereby well.-definedgtretóses were creaied as; follows";,-f o"r/ studied steels 30-50 kg./nifl.?wiaie-f^s^tha^coiitrc»! khl8NlpT lOy 15^0, and 25 kg./mm2. The' 'corroaion medium" conbistéd; either'"(Í) of a. boijing soln¿ of 'Ug^.^'éijí£\t'kij addáí ,6t .%f> Pe chloride j- or, 2) of a-stéam-air mixt.-at 4oO-iê. tá th 'e . la t ter case the surface of specimens was previously

nr.m . e J L . ^ ' ^ W it* 3^3,3 fiad, no tendency toeólh.j.however", they disintegrateds; Because of this tlieeeiteelp .Were „

ty ifa ;thét atea¿iiair/mix..t¿ .'Steel-:2IQ}13-showed' corrosion: -oliij• -.'¿fter• hárcténiiig and .itnipering ¿t 500°, whi le'- stee 1 • :

, corroded' ^nly after hardening; andí'témperingí-át 150 and ;.lyâiiêr: hardening ¿n¿[;;tempering at:l50 and -500 Steel -;

?íü shbWd corrosion^cracking only alter, certain defined heat ';'. •}ni coi$a.i,|{ioris :ahd,J only irijbhe boiling %Clg contg» si>ln» wliile . •Í112H2CÍP5E wás" more, sensitive to /corrosion eracfeing in MgClo;.'. :

soln» rá.'étier^than in air-st'eaiff mixt. / In., general the-aore \ ' .,thérooSynamically/statílé was ;^hé. structure of. a s-teel' the less was thiá ;steel» Object,to.aorrosipn.cracking* . -- ." ^ '¡

coNJoaien crao^.,iig ift 1 ;C1¿ oontg .ajpâi^ pwihgp- tójge'nprál co¿ro.áion

l \ ^

s.te>ei

" ¿<

-Í5ELDS";iíí NIÍHATE SOLUTIONS. .'•

iS

^

PBfOHMATIONr.Oír,. THE SUSCEPTIBILITYSTEÉL3 T0 STÍIESS COHH,OSION Í i

OP OKIXIBNIOT STÍÍBL

'••• • ' ," . • ' Ü •

t V . ,

. bf Vglded: jpiíi ts ' pf; p!£a^¿'"1cí^fj Mh Ié^ ;°Sd"lílí 0 í 8 $ í

$?J£fl "before¿ te¿St¿;e¿i

.-: 9.£

¡f the

Ic-^tof /wélded. i ¿<Hnt ' ' iW' |^ l^Í¿ : ' faB ;a J% : í - -h : | ; »i •• .The;,••'•''

^ ^ i - ^ n . . ' ^-^^^ánüitfr^cfeaMg^eip.piirl^

f;¿^he3''b^;"fr^ .•''

' d ± % i t ^ Í ^ ^ ¿ é f á '1'

347. ~ CH¿(tóe' MD

Sumiteáno Metal I n d u s t r i é B ,

15p,

tlls-i"

^^WF^^i^S^

349* MECHANISM OF STEESS COHBOSIO1Í Iff 'STA1IILES.S STEELS:

ARP-2181-12. Final repor t , 1959 to 1360,

Armour Research Foundation, I l l i n o i s In s t i t u t e of Technology, Chicago- (1962). . \

Tlie s t ress ' cor ros ion of ,auS;tenitic s ta in less s teel in a large, number of. aqueous :arid non-aqueous media has been studied, with the conclusion

'. ' that- no. specif ic . ion, compound, or solvent i s essent ia l to the^crácjting" process i Evidence gathered from potential*-time ourves,

.. '. "acpufeticobservatiohsv-and loading ra te s tudies supports the theorytha t .tlie crack propagation mechanisms i s electrochemical in nature.

' .•;•' • Purtiiermore, d i rec t examination of the surface of a s t ress-corrodieg'";.; • specimen by. the electrochemical mapping technique revealed that anodic

'••'.• : zones Coincide' with crack s i t e s . I t i s concluded that invest igat ion• of tile pre-crackihg-period of exposure i s the most promising area for

"-• : -further s£u'dy.

350. 'HEW STAINLESS STEEL TO RESIST STRESS COKROSION CRACKING. .

Metallurgia, ,77:464, 237-38; 1968.f

A high«-Cr f e r r i t i c steel , with good resis tance to s t r e s s corrosioncracking has been developed. A typical s teel contains C 0.03, Si 0 .5 ,Mn. O.6, Cr 15.7, Nl 2 . 5 , Mo 1*0, and Kb 0.5fS, láechanical propert ies

: a t room and elevated teiip. were determined, and welding characttristfficcha rac te r i s t i c s s tudied. Studies of corrosion res is tance and s t r e s s'corrosion.cracking in various media are reported briefly.-

•351*., SOME PHYSICAL CHARACTERISTICS OF AIS I TYPE 304 CONTAINING NITROGEN.•'• •"••" (Report 438-B.) THE RELATIONSHIP OF NITROGEN CONTENT OF AUSTENITIC

STAINLESS STEELS TO STRESS CORROSION.

EURAEC-1732 34p.- 1966.

352* A STAINLESS'STEEL TO. RESIST STRESS CORxlOSION. CRACKING.

Engineer, 225:5860,' 777$. 1968. . ' '

Austenitic stainless steels-fail by stress corrosion in hot strongsolutions of chlorides and, aatUltic. substances, especially in heatexchangers where hot.gases or liquids^are cooled by water. Ferfiticsteels are resistant to stress corrosion, tut. ordinary corrosionresistÉince is limited and post-weld heat treatment is needed. ',

- 131 - Contdw

357.

A f e r r i t i c s tee l F.V. 702 has been developed wliidi-is frees ^*6m theabove 'limitations» Chemical composition i s C 0.03, -Si'0.5# iíh '0*6,Cr 15.7, Ni 2.5 Mo i .O, and Nb 0.5^.. The. Or, Ni>f and Mo. contentsconfer general res ia tance- to corrosion "and the Nb and control of

' C ensure res is tance to weld decay; The' structure.remains f e r r i t l e .Tensile propert ies at room temp, on sheet 0.128 i n . thi*;k are UTS44.5 tonf / in 2 (-70 kgf/mm2), 0.2$ PS:3,8 9/ tonf / in 2 ; (60 kgf/zma2).elongation, 15$ on 2 i n . af ter soaking, and at •.850°C for 1 hi on a 3/4i n . ' b a r , propert ies were-at 20°C, UTS '45>6-:tóíif/ifl t (71 kgt/itun2),,0.2# PS 32.5 t o n t / i n 2 , (51. kgt/mm2)'arid :at 50Ó°C OTS 31.4 tonf / in2,(4.9-•.\LgtJw£)t:Q.Zfa.'B& 24.9 tonf/ in 2 (39 kgf/mm2). -Elongation (5I>)was ,22^,at botli.tanp. At room temp; the Ijapact.'.s.iren-gih is. l l a i t e dibeing 11 i t / l b f (Í .52 kgf/m). de ta i l s of welding and.;córrqsioií. t e s t sare given» . . , • .

353. (PV .702) STAINLES,S STEEL (VERSUS)' STHESS' CÓÉROSIOST; v

Engineering, 205:5328, 8317.1968. :. •'- . -' : ' ' • '

A s t e e l P7 702 produced by Pirth-Vickers for service in 'condi t ions• where s t r e s s corrosion i s a po.ssibiiiiy i s described. Typical

••;' ; composition i s C 0,03, Si 0 .5 , ; Cr Í6 .0 , l i i ;2 i -5 ' ; foLoi- ind Nb 0.5$;,The,steel i s essent ia l ly f é r r i t i c $ : i t remained uneracked af ter 500 h inin boil ing 42 % MgCl, under 20 ton in" 2 s t r e s s , and also af ter 500 hin &fo ITaCl a t 250°G, a t 1.0 tons In"2 s t r ess under 0 at 1500 lbs i n .

3 5 4 . STRESS CORROSIÓN CRACKING OP Fe-Cr-Ni ALLOYS -IB CAUSTIC. ENVÍRONIáEÍJTS." . . . P e r i o d Covered! J u l y 1 6 , 1 9 6 9 - O c t . 1 4 , 1ST69. •"•; / . ".'•• : , . . :;

COO-2018-8 s

355. -STRESS CORROSION CRACKING OF Fe-Cr-Ni ALLOYS IN CAÜSTÍC ENVIROHÍIEÍJTS.Period Covered: Oct*. 15, 1969-Jan. 14, l 970r iS ? ' :E - •

COO-2018-11 37p.

3 5 6 , A STUDY OF° THE STRESS GORROSIO^JEHATÍIOR OF STAINLESS-STEELS»( Q u a r t e r l y , Repor t ; Ñ o . I , 1 . S e p t . - ^ i } . 1 9 6 4 ) . •.'!•• ^ ' .,'' :

Euratom Joint Reeearch'and. ¿evélopmeni; program, 36 p .

EURAEC-1309 • „ „ = r - •-,/

- 132 -

357. A STUDY Oil THE STRESS CORROSION OP STAINLESS STEELS IN CHLORIDESOLUTIONS.. (Final" Report.) ' •

: ÉÜRAEC-Í947' (Pt.l) i22p. Oct. 1967. ,

Work Performed under United States-Euratpm Joint Research andDevelopment Program. . • •

Tests were, performed on eight grades of stainless steel, four with anaustéñitic structure and four with ah austeno-!-ferritic structure.Testing devices u'sed for the study are described.'. Sample preparations'are summarized. Tests in boiling concentrated solutions of magnesiumchloride to 44$-at. 153°C, calcium: chloride to 62$ at 150*0» andsodium chloride (5N) at 107°C were performed. Results are given.Stress corrosion tests,in. chlorinated waiter at 150°C were carried.but at various pH.in low-pressure'autoclaves. At 200°C, tests wereperformed at pH of 2.6,.6.5 and 10. Experimental data are tabulatedand results discussed and compared to previous results.

- 133 -

ADDENDUM

35S. Balezin, B A et al

' INVESTIGATION OP THE EFFECT OF COJEjüÓSION IHEIBITÓHS'Q1ÍTHE CRACKCORROSION OP STEEL IX18H9 IN MAGNESIUM CHLORIDE-SOLUTION BOILINGA T 1 5 3 ' C . . .• ' . •. ' • • : • * -." • '. ' ' •- '..'•

• ;

' .• . . ' ' . • - . - . . . , . . • . '

Zhur, Priklad. Khim. 33, 1300-115 I960. ....,, . - .

The degree to which inhibitors designated PB-5, PB-8,. BA-13(a condensation product of benzylamine and paraffin), and KI

• prevented; crack corrosion of a steel containing 18.44$ CΓ, . 9.91$ Niy' 1.39$ Mn, 0¿.ee?á Si, and O.Ó&/0 0 in a saivurated Mg:ci«. solutionboiling at. 153°C was studied on specimens kep.t under a stress of 30

' kg/mm2.. It was found that addition of 0.1 volume, $ of HC2. to thesolution increased crack corrosion by a factor.of 1.2 and. the generalcorrosion by a. factor of 1.5. Tlie. primary, layer formed on the metal

• surface which initially localized the attack and protected thesurface, was slowly dissolved and replaced by a'secondary fil.niformed from.the bydrqlyais products. Addition*of PB-5 and of BA-13together with KI protected the steel against stress corrosion whilePB-8, BA-12, and KI alone slowed the corrosive attack withoutpreventing it completely. Cathodic polarization at a current ,\density of 0.005 milliamp/cm^^resulted in the complete protectionagainst attack by boiling MgClg containing 0.164^, KI. Anodic,polarization on the other hand reduced the protective,action. Theelectrochemical behavior of the stressed, specimens was determined.Addition of iron salts negated the befeficial'effect of PB-&, buthad little influence on the behsvior of BA-12. Abstractor1s note;Russian steel designation lCrl8Iíl9. However,. X and H .are notelement names but initials only, transliterated Kh and_H.

Birchen, 2)} Booth, G C. . . .

STRESS, CORROSION CRACKING-OP SOME AÜSTENITIG STAINLESS STEELS. AS;AFFECTED BYt SURFACE TREATMENT AND WATER COMPOSITION.

CONF-28-3 , -

From International Congress on Metallic Corrosion, New York, Mar. 1963.

A simple static autoclave test was «developed for studying the ,l ; •stressL_corrosipn cracking of áustenitic and stainless steels in -high-temperature and high-pressure water of Relatively-highpurity. Chloride contents varying from 0.2 ppm upwarda in waterinitially saturated\with air can, cause cracking blinder these •conditions.. A threshold strain was observed'below which rounded pits •occur and notsracks develo. Atoove this strain cracking is precededby the formation of angular pits.' The threshold strain is reducedby pickling/ Emphasis ig given to the need ¡jto a%oid° oo'ld work on .stainless steels that sre to be exposed to á "pressurized-water «° °environment. " ' - • e° - . . = %, • •" .= ,

- "., x .- - - - 1 3 4 - • • « - • - • 'r '• •' . • "• ' ' " " ' '

V " . ' - • ' ' * t.; ' "•" "f . ••

t"'8

360.. Clarke, P E; Ristaino, A J.

INVESTIGATION OP CHEMICAL IKHIEITORS FOR STRESS CORROSION CRACKING OP'• STAINLESS 'STEEL, (Summary Report for January 1964 to, June 1957.)

• : • . • • - " ' ' • ' • . . . - ' . . . , - . . . /

Since recommending coordinated". phosphate-pH control for the STR boiler•in 19.50, numerous laboratory, tests,'experimental boiler tests, andactual service tesis have, been made of this treatment with andwithout supplementary chemical inhibitors, to. determine its merit

' .in maintaining proper waterside conditions and particularly in ' '- preventing stxess corrosion cracking. R has been determined that thetréatflent originally recommended affords adequate protection forboth mild steel and stainless steel surfaces completely submerged J.n

, boiler water.' However, stainless,steel parts exposed intermittentlyto ,the boiler water and its vapor are riot protected against stress-corrosion cracking if. both dissolved oxygen (or certain oxidizing-agents) and chloride ion are present. There is evidence that caustic

•', alone will cause cracking under the same conditions. This daaage :

has been prevented by supplementary treatment with sodium sulfite•\,oxygen scavenger.. A more pracitcable inhibitor for the stress.. corrosion problem still is being sought.

" ' • • ' . , , • • " ' ' • . ' ; • ' • - " • • • ' , '

361. • Coleman, E G et al • _ •• ' '.' :' . ' '

'••"' ON A SURFACE ENERGY MECHANISM FOR STRESS CORROSION CRACKING. A.: /•.* MECHANISM 'FOR STRESS CORROSION; EMBRITTL'EMENT.' ....'.'•

ARP-2152-iO ,, I960." ;. . . ; ' .' ' . ,

It-has, been demonstrated that strés.s corrosion cracks, can be initiated. on continuous1 loading in a suitable-medium. Results are shown for

. , ; stainless steel immersed in boiling MgClo solution and for a Mg-6$ Alallpy in Sftúeóus NaCl-K>Cr6^ solution at room temperature.1 Tlii3

• behavior has been μse1d^ to analyse .the. stress pprrcvBioh cracking ..

process in terms of the dislocation theory of brittle fracture*It is proposed that the mechanism of cracking originates from a .condition .of reduced surface energy brought about by adsorption of •

l.

..:', , soníe ion species from the "surrounding'medium..; An analysis of the ,grain size dependence of the fracturé initiation stress in the •*stress corrosión media ,leads to. estimates of reduced surface, energiesof the order oí 100'to 200 ergs/cm2. ' V

- 135 -

.•^•M"^..^-.^i

362., Cc»lou, H eg. al

. 502^5 SENSITIVITY TO STRESS-CORROSION AND tNTÉRGH&NOLAR ATTACK 01HIGHir-NlCKEL AUSTEiTITICALLOYS.. . ' '" .. - ' . , '" ' ; , '

\ ': • • • ' - • " ' • . " ' ' ' • ' • • : ' " ' • ' • - ,

:"

: •

*., Corrosion, Vol. 22, pp. 280-290; 1966.; • c[ . . .

363. -''iGul t akneen j E A '• y . '• ''• ; • . ; ' ' „ • " : / • . " ' • " ' ' ' ' ' • " . . , :

UNUSUjkl' GRYSTAL GROWTHS OBSERVED IN- THE HIGH-TMEERATTJRE CORROSION. OP304 sfAiNJiESS STEEL ATSTD 'IRON. • (Resea rch - ,Repor t . 6 -9460Z-1-R5 . )

.19p. 1957 .

Electrbn microscope' and electron diffraction .studies were.made on thecorrosion products5fornúiLd on 304 8tai,nless s tee l and i ron in dry a i rand oxygen, oxygen saturated a t . 25°C. with .'..water ?.apor, -and .oxygensaturated at 25°C with HgO. Vapor pliiS a few parts per million ofÉC1'vapor. In addition %o the formation of the normal layer type ofoxide fjilmi many finé oxide whídkers were formed oh from at 500°Cin wet jand dry oxygen atmospheres. These whiskers grow nearlyperpendicular to the stxrface and were 300 to 1000> ángátromé thick

| ?i g

and' up |o 470,000 angstroms long. The density of;whiskers was l<? • toiO9 | 2 C l i

p |iO9 per|cm2

iTh6

ty ;p | oxide was ©C-Fe205. s With s ta in less s t e e l , oxide

whiskersi of CrgO^ were formed 100 to 500 angstroás thick and up to .-;.5*0,000 diigstroms in . length . Some areas of the specimen were fSeefrom whiskers;.'wh"ÉLe other areas contain up to 10^ whiskers per cm2*In atmospheres containing HCl'vapor at 600°C, -fan shaped single-. .crystals,! of CrgOg, were forjEed."/ These grow .-nearly perpendicular to thesurface-' ^lid were about iOO..angstroms ¿hick,. ,10,Q00 to 5,000 angstromsin heigli^ and 1-©0,QPO angstroms I8rig¿ These crystals" appear.,in . •''. .-'paral lel ; Hayersi Pre-straining of, the specimens with str-ess levelsgreater tSjian^the yield point greatly âccelerates the. growth Apf the, fanshaped-prystals.; . I t was proppsed that this crysta l habit may; be "' •;,important'Sin dfetermining whether a" given alloy i=s susceptible-^ to ; 's t ress = cóír~dîon cracking. . - ;",--• -',, ".'.-.,..,"""' ".,.,,'?, '••^'\o.' '•.'•" . "'• V '-[

364. English-,¿jjl I ) Óriess, J b = ': ; • ' ';?'.. . •% ' , ' .' • • • V l \ ' ; - ' | " " \ , ' - ' • • . - • - • - • . = • • ' • • ^ ' i ' V 1 ' * : . . • • • . o \ \ : - ' - . ' • "•• ; :

, ' , STRESS'COMOSION CRACKING" OF-AUS^SKTITIC STAINLESS -STEEL I N URAITYLSULFATE SOLUTIONS. » • : ' " ' , , - ^ > _

• \

TJie eff ecteit of a rtumber of variable's on the stress" ctfrrosion crackingbehavior ofi two different ,êats of, ,lfpe S4? stainless steel wer.eexamined inIsiaulatia aqueous honogeneous, reactor fuel solutioncontaining low coneWEtfatione'of ^hloride lone» o = ; °. ° ,

'*$.

- 136 - Contd.

/'. i

The fuel solution-consisted of uranyl sulfate, sulfuric ac¿d, andcopper sulfate. Tests were conducted in the temperature range of50 to 101°C. .Although the two heats of stainless steel were nearlyidentical in composition, specimens from one heat were consistentlymore susceptible to crocking than specimens from the second heat.•Chloride concentrations of 25 to 500 ppm were equally effective inproducing cracks. The higher the dissolved oxygen content in solution,the moré numerous and intensive were the cracks. . Cracking was stillobserved, however, in the absence of oxygen. Urahyl sulfateconcentration was an important variable; at concentrations of 0.40Mand greater i no'cracking took place with chloride present. Sodium-dichromate. was found to be an effective, cracking inhibitor.Pretreatment of. specimens in chlpride free fuel solution either beforeor after stressing greatly reduced cracking susceptibility duringsubsequent.exposure in the.fuel'solution containing added éhloride.

365. Gopsp», II Rj Lang,, F S. "

STAINLESS-STEELS ¿ESISTANT TO STRESS CORROSION CRACKING,,

U.S. 3,159,479, 1964; 5pp. (Patent)

Bént'and bolte.d austenitic Cr-Ni steel specimens about l/8 in. thick,"considerably" stressed while suspended in boiling'42$ MgClg solus,at 154e in .flasks having reflux condensers, resist cracking forat least 20 days if the lii content is ^19, Cr 16-25, P ¿0.018,CO.Ó7-0.1, Si # 1.6,,; N ár 0.045 with P + t £k 0.C65¿.. Mri 0 . 2 , Cuáé 0.1,Bi, As, and Sb each ^0.015, Mo .¿«0.05, and A3. either below 0.05 -or above 0.06$. Tiai^d Nb are undesirable because of'lowering theeffective C content. \Forged, cold-róiled, annealed, and sensitizedspecimens of 30 cómpnp. were tested .to. derive these conelusion»,which were approxi the same Irrespective!of such,treatments.. Thecracking was'• generally more, rapid as the divergence of the coapn..from- the stated limits^ increased.. -Vacuum melting* is riot required for ,resistance to this type of failure., but^ p. 12?á¿P,of more such as .'..improves high-temp, st'iren th must.be avoided. ...TlieJIi content need notbe ove-r 35$., Tlie Hi, ol nd .? liaits:are all .especially crit. ..;•,U.S. 3,'1-59,4.80j 5pp. Wi'íjbía,..,higher Si, the ;C limits, are not crit.,'.the.prermissible compn. limiis for no cracking in the ,sam,e; test for 30-.,days' being as given, in, he previous patent with- the exceptions-1 of -Si lé'1.7-2.5^ and C.up to Ó.0j4$>yTlié conditions of. testing, were the some,and results fVom 23;compha5..,0mostly cphtg. ¿-1.7 i ;Si,..are- reported, anddiscussed. The Ni, Si, aljid P limits are here, considered esp. crit.

.'n137 vi-'*-'

J

•366.. 'HoFells, E-j; -•McNárjr, -3 A

3 6 7 .

MÓDEL TESTS OE. llkTMlAIiS-'WATER- REACTOR PLANTS*. .;•; 'V,'_'_. v¿

r a s i o n 1 6 , 2 4 Í t ~ 5 t y i 9 6 0 , \ j .'",• : •. ;;:••• •';-"•"•"•'';•.-' ; - ' - ' ' i 1 <•'• \'~ .,. _,,'

• Anêvaluatiori waeJ zaade 6f various' materials, on.<ihe secondary, side of-boiler mqdeis built and:operated, in,simulation:;of>,a.' full- spale unit _;•„_i 1 á'pressurized #ater:t,nuclear, power p&xit.. Materials' tested-included.•stainless steel j, carbón .steel j Groloy 2l/4 Gvqloy' í-6-i,'. nj^cJce^. .;

!' #In'coñél, and'Mbnéi.- Considerable attention was given to problems ';involving, stress .corrosion cracking¿. particularly/:of -Type 247 í ;.stafilless stve.el .tubing.Mother topic discussed dnclú^é,control*df ,'. ,dissolved oixygen. concentration; pitting corrosion.,, and -^location of ,.rtubing áréaé most susceptible to corrosion». • ' . ..f ..,/•;. -' :

3 6 3 .

E o n n q . u i s t , 4 • '" ••'•':•--'.'' .-.. - :-,.;-;

THE EFFECT "OP"DISLOCATIONS hé, CEmiGALCORHÓSION CRACKIIíG;Ílí;FACE!,COÍíTEREp.CUBIC

,,ON TEIl''STRESS

JIcadaat

• -\"[ ''J.ernitofiter.., A i m . , S v e r i g é 1,51; 1 0 - 1 1 , , ?65-80P}.;19.67* ,-; •;.•;•,.:.;/

368. •' Ifeumann;' P-Dj Gri#ae, J: C

-.,.; ^.STAINLESS STEEL. AMD. OTHER; ALLOY'S Iff EIGE.. TEfPESAT'ORE -1AÍM."' \

'jv> 19:, 345t-53'jv 1963/-

An extensive study;w^s c^hduííted on the susceptibil i ty, of Type,347s t a i n l e s s s t e e l to stress. 'corrosion cracking .in high íemp'erátúre water fover wide ...ranges.,',of <Hchl or:id.e/cf¿úc£ñ=tration, temperature ¿ ^ó^gên ' -.

,concentration, «and pH. -No erac|ting rifraa.pbservJed at .a chloride; .conp.V ., .concentration,of 5 ppto, but"cracks vrex&- pbsérved.ai XO ppmíand higherat temperatures of," lOOf C;'andvaboveV ifaxiiiium -sjasce'iftábillty wag,*. = . v

found bétwéfin'1'SO and 250fC» but np< clacking was sfound -b'elow .100°C. .'No pH effect ¿was noted, ârioi'-5. heat' treatments ándL surface preparations'showed lió appreciable Jeffect.' .Mckéiplá t rng, ' e#en .with a only3 pa r t i a lcovering of the surfape, waá found to íhhibí i , s t ress .corrosión cracking ,completely, while,ohromate and phosphate in .solution/.weife^éfi'jectiye

^n-ily—^^higfa^JcQiiCBiLti^t;^ s teels =- ~— -were* similar invb,ehaviox to Type"347*,stainless s t e e l , and three f e r r i t i cs ta inles i ; Steele exhabited only sligfiily be t ter r.esisiarice to '• ,..''.". °cracking."Of five h|gh n icke^ liigh chromium alloys tested^ onlyinconel exhibited complete fmmimii|ôtQ stress, ' corrosion cracking.

. Ca|t chromium niojcel^ sJa^nlee&iêls i wiers °foupd tp be extremely-res i s t an t tó°etreap;corro8ioiêraokíng as ¿long as they were cnot•subjected to 0034 wprking oj^plaetip„deformation.

370. P<

Reelmothin£0:

'• \i ; -

Once stressed above the yield the resistance to cracking could notbe regained by annealing* Á number of the .alloys tested in hightemperature water were also tested in boiling 42$ MgClg* It was foundthat "-lie susceptibility of an alloy to stress corrosion cracking inboiling 42$ MgClg solution is not necessarily a measure of itssusceptibility in3 high temperature water containing relatively smallconcentrations of chloride ion.

369".' Pashos/- T J

'STAINLESS STEEL FAILURE INVESTIGATION PROGRAM. (First Quarterly Progress. ,. Report, February 15r-June 30, 1965.)

. GEAP-4915 • 1965.. •

A number, of type 304 stainless steel clad fuel rode operating inboiling water reactor environments have failed the to intergranularcracking. Factors that may affect intergranular cracking of austeniticstainless steels are discussed and the research program proposed is .described. The program consists of the investigation of the effects ofmaterial composition, coolant environment, irradiation damages,

• . and operating stresses on clad cracking. In preliminary corrosiontests, high purity stainless steels proved more corrosion resistantthan type.304 stainless steel. Intergranular attack was produced byboiling IINOg +Cr'+'solutions, transgranular attack by boilingMgClp solutions, and either transgranular or intergranular in FeC3g

solutions at 343°C depending on test variables. A cladding specimensection through a region of localized strain revealed an inciptentintergranular crack starting on the outside surface and extending r%/&mils across the 14 mil cladding thickness. Eighty-four references onintergranular cracking in austenitic-stainless steel are included*

me

tic

.370. Pennington, R T

NUCLEAR SUPERHEAT PROJECT ELEVENTH QUARTERLY REPORT, JANUARY-iWiRCH. 1 9 6 2 . ..- V -• ' • - • • •• ' ' ' " .

GEAP-3924 :302p. Í962.

Result of a study concerning the optimum type or types of superheatelements are presented. A seven-rod fuel element appears to be themost promising design for nuclear superheaters» It is recommendedthat'the combination-type element witli internal coolent channels beinvestigated. Physics- vu/rk during period* was devoted-to the core'for a 600-MW(e) reactor.. ; ; . ' .. •

~ 139 -

Results of analysis of flooding, effect's on reactivity are presentedalong with' data 'on effects of moderator temperature and control' rod worth. Examination of fuel element 8H-5A firter tradiation at750*-845°F for 1000: hr. revealed small cracks in .the cladding ofihtergranular nature. A description of the NUSÍT Irradiation operationis.included. Data are included on the ESH-1 and ÉSH-2 fuel .design.Data are included which- show that'the stainless steel tubingrejection rate is about lO/o* Development of ¿velding parameters for10-and 20-mil.-thick inconel, Hastelloy X, Hastelloy N, Ni-O-Nel, andstainless steel is reported. It was found that end plungs involvingthese alloys can be welded without undue preparation. Test-work done.on type 304 stainless steel stress corrosion is summarized along withresults .'of a 1000-hr check on-stress corrosion of Inconel and Incoloy.Results are also included- on the effects of ll-00°P steam on HastelloyW and Inconel, and on the SH-5A and MuSu. tests. In mechanicaldevelopment efforts during the period were devoted to procurement of aplastic shround for air-water testing and to a series of steam-watertests. A designs and irradiation summary for SADE fuel el&nents isgiven. Work on the E-SADE is about 70$ complete. Information isinduded on design of the 75-Mw(e) Mixed Spectrum plant along with datainformation of the Mixed Spectrum Superheater Critical Experiment. •

373.

3 7 1 . Posey, ¥ j ( e d . ) •

•PROGRESS REPORT Ü0.46..FOR APRil-iiJD lilAY 1956,HSA Research .Corp. Ca l le ry , Pátina.NP-6787 • 30p. . 1958. ' . ' '

. . . ' . . . " _ . . , * ' . . . • . • • • • - ' • • . . . .

The response characteristics rpf three chromel-alüiaei thermocouples toa ramp function change in temperature in the' Bottis Foaeter Flow tube.with the Core I need cluster were determined. Experiments to obtaininformation' of film boiling at elevated pressures in a forced-convectionsystem were performed. The water parameters covered were: water inlettemperature 500 and 600°F, pressure 2000 psig. and mass flow rates0«4x 10*> to 1.5x lO6 ob/br-sq. ft. Stress corrosion cracking óf 304stainless steel pipe by exposure to chloride-bearing water is beinginvestigated. Fission product release and zircdmium-water explosionhazards in core.meltdown were evaluated by melting t\wzirconium-uranium subassembles' in a, steam atmosphere. . ,;

374,

- 140 -

372. Posey, ¥ J (ed.)

on

e

PROGRESS REPORT NO.50.FOR DECEMBER 191958 AND JANUARY 1959MSA Research Corp., Callery, penna.

glp. 1959.

• Film boiling runs made *n tubes pc .taining water showed considerable.. axial variation árouíiá the lieat exchanger. Heat balance at low JaKflows was off by abou*!; 30$. Loop modifications were made, and testswill continue. Studies of chloride stress corrosion on stainless steeland Inconel pipe were conducted. The stainless steel stress corrodedin one to. four days depending on thermal cycling temperature. No coatingwas found which would'provide extended protection* Coating withwater glass provented cracking in one 100-hour cycling test. Inooneldid not stress corrode? however, pitting occurred in a 5-week thermalcycling test, ..Seventeen protective contings were tested, four of whichappeared', to: of f er the best projection. These include coating 9 (Mn base)»coating 5 (Ni base), coating 10 (Al base), and coating 6 (Zn base)*

ba

;ion

373¿ : Turner', Fj Richardson, H K

INVESTIGATION OF CRACKS IS AS 18/13/1 STAINLESS-STEEL AUTOCLAVE.

IGR-TJtf/C-1015 lip. 1958. ,

A stainless steel autoclave used in the corrosion testing of metalsin water failed by stress corrosion in the vicinity of a weld.Welding had been by metallic are using flux-coated electrodes and aslag deposit was found at the weld root in the failed area. Theflux and resultant slag deposit were proved to contain significant

, ampunta of chloride; The slag deposit was connected with theautoclave interior via the interface between the base plug and wall.•This provided the corroding medium which in the presence of waterresidual plus operating stresses caused failure by stress corrosion.cracking. . Recommendations are made for the avoidence of this typeof failure. : ..

374. Waber J T| Waber, S : ,

ACCELERATED CORROSION TEST OF STEELSf . .

1 LA-191.3- 27p. : 1950V : • .

General tests have been made on materials being considered for ductwork in the new CMR laboratories in an effort to determine which wouldbe most satisfactory. Materials tested were "A"•Nickel, "B" Monel,

- . Inconel, Inconel B, and Types 316, 316 ELC, and 318 stainless steel.

-141 f\ Contd....

•'••».•-

General accelerated corrosion tests were-run in.a. simulated*"'bobd withthe. metals in contact..with the.fumes of six solutiona-fiv concentrated-apids 'and one alkali.. The-.saw.kerfs in .e.ach specimen5 were1 examined for' stress corrosion., Welded specimens of the;,met&lS' were' álspitested forstress corrosion cracking and for, intergranular .'attack'of tlíé'-'íieat-.

. affected' areas. . The ,,stainless.steels and inconel showed--the'bestresistance to /general'.chemical attack:., inoonel offe,rs tlie-addi:tionalfeature'of being free from, stress, -corrosion- susceptibií.fity>'and- pitting»Hence, i^ is preferable by more than a;slight.-margin. 'Ih< general,the. results, ofythe.se corrosion tests . agre.e .quite well with' general

1 •'commercial experiinérice. ,The use of inconel; is. recommended for the duetm ' • mm- mmmm. 1 ^m " I ^ _ ^ k _ ^ _ Mm mm* mm- T ^ 'mC^ ^ ^ 1 h ^ ^ - — * - _ ^ _ . - m_ A A rntm, Mlm* mm* dX> 4ri« ^m ^ i A | ¿*- > k my^^m*m « ^ ***m> 9m . ^ ^ . ^ ^m* m*M " - b h Jt mmmm "irnmmt *m a ^ . ^ ^ U i _ ^ \ ^ ^ ^ . ^ •• ^ ^ . ^ ^

-and:, wmagnesium chloride reagent. .The-sample

5 abundantly after'a few; hundred hours. . Considerable protection wasafforded.by heat-treating the lubing at 1950°? for one-Salf hour andthen air-cooling. Where stainless tubing is used for drains, theÍ95Ó°F heat-treatment is recommended. 'It is-also, desirable- that thesteel be pickled before being passivated.

375. Wanklyn, J H et al . ;•> • L ••• • ; -: - ' '

• , THE COEROSION OP AUSTElSflTIC STAINLESS STEELS .UHDEB^.HEAT "THAiiSPER' I N H I G H - T E M i E R A T i m E ¥ATER. •. .*.•.••.-•', • --.- . :; v- " ¿.'•.'.•'Í ..;•'-.t-¡? •'• •

J. Nuclear.Materials/iV 154-73; 1959Í

'corrosion of'.two is/s austenitic; stainless- srbe'els. under' stress andboiling heat transfer',izi oxygen-free water .at pH. 11 and 280°G has beenstudied.' On plañe;' surf ace'is, .heatj transfer, does . notr'. sighif icaritly.increases' corrosion in. times up to :i-000;hours* .. In •crevices' where heat'transfer'caua.es. superheating and concentration of solut-i^ns^ stress'ciorrosion. cfacking 'occursV Tliis is due to the caustic- álkáli(60 ppm)required to. raise the pH to 11; by compa'rispn, a chloride concentrationof 0.5 ppm in the bulk water has a neglible-effect* -unlike thepreviously reported stress corrosion by.caustic alkali,"the cracking 'is wholly intercrystalline*-~ Tlie minimum superheat and causticconcentration required to produce;, it, are* about 25'to 35?C and'40 to "50 wt. % KOH, respectively. The better-known transcrystalline crackingappears to require higher, concentrations.¡the» this.-'-In the'-/appropriate solutions intercrystalline corrosion is.possible in,virtually unatressed metal, but mechanical-failure is more rapidat .stressea of, the order of 20,0Q0 p,ai (MOO Jrg/cm.). '•• . •-' .

- 142

376, White, B E

STRESS CORROSION SCREENING TESTS OP MATERIALS FOR STEAM GENERATORTUBING IN NUCLEAR POv7ER PLANTS.

- . • Corrosion 16, 320t-:41; 1960.

Nuclear power plant steam generator tubing materials were tested fortheir susceptibility to chloride stress corrosion craoking. StressedU-bend specimens'were exposed for 24 hours in a tilting autoclave to

' botft the liquid and vapor phases of a high pH synthetic boilerwater solution containing oxygen, phosphate, and 500 ppm of chlorideion." The results indicate that AISI Type 347 stainless steel, thecontrol material, and Carpenter TMo are about equally susceptible tostress corrosion cracking in this test environment. Carpenter20Gb and Type 304 having low cErbon .-and nitrogen content displayedimproved resistence. Inconel, Monel, nickel, and titanium displayedcomplete resistance.- Ferritec steels were crack resistant but • •they did suffer pitting attack.

377. MECHANISMS AND SOME THEORETICAL ASPECTS OF STRESS CORROSION CRACKING,OF AUSTENITIC STAINLESS STEELS. . ... . '

Corrosion 15, No.9, 103,106,108,110; 1959. ,. -

After, reviewing briefly the generally accepted causes of streas.. . . ,corrosion cracking of stainless steels, design of heat exchangersintended for use with chloride containing waters is considered'^ .Conditions causing stress corrosion cracking make tube-side coolingbetter tiian shell,side, favor-designs eliminating stagnation and- makemandatory operation resulting in full water boxes. Velocity '-$¡n-:.excess of - 5 fps is recommended. Insulation containing chlorides shouldbe protected from:. moisture and water'temperatures kept as low • , • ;..*

•••••_ as. possible. Good aeration is necessary and recirculating waters . • .Blióulá', contain no chromates or other o¿rxidizing eompounds. While pH.'..'

J ' is .not, critical-,' this-does not'Tmean that pH in concentration cell • '..anoiytes is not important,' ' Theoretical considerations involved in the.-.stress corrosion:cracking phenomenon are considered. Plastic deformation,

which, results, in. the., accumulation of .stresses at barriers along a slipplane/ is viewed as a precedent—tó cracking. Nickel, among alloyconstituents, is seen as beneficial in preventing cracking^ andthe reasons, for this.are suggested as an avenue of fruitful" investigation.The nature of the corrosion phenomenon, involving 3uch complex factors '

as films, adsorption effects, and electrical double layers,are. mentioned, as areas where-more/study.would be rewarding. Possibility of thermal orelectrochemical concentration of chlorides must be designed out, cleaned^

• ' out, cleaned out, or kept out of industrial cooling water,systems. '

- 143 -

3 7 0 . G r i e s s , ' J . C e t a l ' .• • . • . •;; .'..;

QUARTERLY- REPORT OF THE SOLUTION -CORROSION GROUP FOR THE PERIODENDING JANUARY 31, 1959. -. • < «•.. ' • 3 3 3 '.

CF-58-1-72 69p. 1958.-

3 . 7 9 . G r i e s s , . . J . C e t a l " • . • • - . / . • ' .

• >• QUARTERLY. REPORT OF THE SOLUTION CORROSION GROUP "TOR THE PERIOD'; ENDING APRI.L 30, 1958* " , . . .-.'•/- \ ; \.

; CF-58-4-131 j>¿. . 1958.J\::I' ;

380. Griebs, H C et a.l •'• . - , . • -."-*'

SOLUTION CORROSION GROUP QUARTERLY HI PORT FOR THE PERIOD ENDINGOCTOBER 31, 195.7. . . . ' " j ' .;-' 7

' VV-'i '

CF-57-10-80 39p. 1957.

A fifth test of the HRT.core.-pressure-yessél flángs.and transition'mockup was made. No leakage occurred. Metallo&raphicexamination hasshown-the •.occurrence of stress corrosion cracks on the'outside, of astraight section of .type 347 stainless steel pipe'exposed to a tap

. and demineralized water spray. A .hydride phase'was found; ."..'''metallógraphically: in a Tir75A sample holder exposed" to' UOgFTe" and in a

•. .Ti insert exposed- to Og-free UQos.O¿. It, was shown that .SO.-3/4"" inhibitscorrosion of stainless steel in U0gSÓ4 at 250°C-The .initial, run.in the

'.'new all^Ti. loop, loop H, gave. low. corrosion ratfes' on pré^tyeátédstainless stéél coupons. The, second, run. gave higher corrosion.' rateswhich may be due Üb a difference in .pretreatment of !couporis.': Filaisfi f-on'stressed type. 34? ¿tainless steel by exposure in b'oi ih 'arid "'aerated chloride-free UOoSO^ .solution .were.found to' provide • ai léss-'tsome protection to the. alloy from stress •.corrosion crocking when"'

-.-_,-. exposed in a similar solution containing .chloride'ions.- A number ofalloys' of Zr were tested in siinuía-ted HRT fuel/solution; • ..:.V-'':!, •.. •

3 8 1 , G r i e s s , ' • J . C . e t a l •/'/'. ... "-•*., ;••• \ ' . i : ' ':;-'-/ "'.^ ';•• •"',-''' ".'

-....: SOLUTION' COÉBÓSIÓN: GROUP QUARTERLY. REPORT FOR THE PERIOD ENDING•: !.- J U L Y 3 1 , 1 9 5 7 , '. ' •,.,',. ..',v, .•• : v • , • ' - , . • • • > - - ' • ' ;. ''•;..•"'' .'...

CFW57-7-121." 64p. 195?. . . -.; ' '•••'.-

-•144 -

v 3 , 8 4 ^ Í

- ' ' •'. *

; 382-

• • ' . . ' • ' . • , • • • 1 . . • ' f ' ' ' " ^ ''. . ' "i ' * ' • '^ > ' - . ¿ • ' , , ' - ' . - *

Griees, J O, e t , a l ' '

CORRO SION BY. SOLUTÍOMS.': , .:. • ' . " . • . • • • ' .

'

383.

THE' , CORROSIÓlí: CRACÍCING. 0

:•,,;;L17pV .-IJ,. 19,

á¿\.ê/'%ííe"oí¿\o'f^t^íá¿e:'--pTepai!atibn onl the . . incidence pf s t r e s s . . ,->po¿ro'si,oá praókin^, pí;'.T¡y-p^.31.0 s t a i n l e s s : s t e e l was / inves t iga ted»

' > ! - . ' . '•

•^wérVpreparéd, by íaéchanical'pplislítng.at t | i r te levéis, of roughness, '••eheinic'ál-poíishin^, y1acûia,áâeálingr' and eleotrochemicaí polishing.;

'/:!k:'éiTe'^rahge óf/.g5éan-;-t±iííes1-?tb--cracl¿ing wasíndted.Y'.'Méán; .times _-•/', \ *'', ¡

•differed fcy about á factor óf' f ive . . ^ ia t r ibút ioh of cracking tiiaeáâísó:''.Viiêd.âbbut^t4e;._niân value's» üíechanicáliy ?p,óiishéd>specimensí ó?aekéct. in° shorter, -tiiñe;^: than - thósé, 'cheQically.^••polished- or'" vacuum '";?í ánríéaíéd.,, Thlev&ata '«eíe". rationalizeM in.-tlie terms Qf probability of

s t e p s . ~ \ l : ••:',• * • : " " , « . ' . .'••,•:•:.••'••'•• • ;'••

•''-".• >,. •'.-..;

,W • \

• • . 4 ( , '

; í l íV?STíGATÍiME O P ^ C R í m ^ J Í ^ m i í ¿ E I S S ; STEEL FUEL ELEMENTS.?' ( P e r i o di - C o W r é d ' D e c e m b e r 1 9 6 Í - Augxfst 1 9 6 5 . ) ,•••-". • -! .,- ! .'.-. ; .v ' 7 - : ' " ; •••i1..-^ " = "

1965. . ''.. •..'_ ; ' i V' •-.' ' '. : •"•

An i ^ é s t i g á t i o n iráts ünde^tajcén to elucidate ;the natiirejnebliaMeni, ttéax bV la number of s ta in less s teel clad' fuel',, eliment

. failed^^J-i\-,experimentáí essembirea!in; the YBWR.,. The: experimental -^hêeiigation .included optic'al metallography^ microhardness, ,«;'iHuéi3P',testsif> anodic: polláriífation, :;cheniical 4npilysís áad eleotron-tíyeo^Pf fiaoiograijliy. ,An ettemptvWQ»f.mad.e/ta.rationalize. ••' vobservation onithe basic ófba cracking mechaniem which was eitheVent i ra ly rJnéohanióol o? Chemical' meohani,cal. Such an zpproooh waadesirable in order to aspees, whether thê cracking was'applicable !onljr to . Vα*; speoiphio expjgtriêjit :or ^ «to a broaq.,; range f> reactor 1

'"typi#'"ánd.''"4a4;eri;ai^ -.". Bepa|íee s>ó1fc-";lhe¿lábk of physical0 ir ífomaüon. _no^ difinlfé.éóJÍBlutiOíi régixáXiig eifeer Jfíânieniwae obtaineiiaíWhile •^l :i«êh0<-*Te4-i^J4.at. iiaiie.,ê'°9eeme tó favouí A

^ l ^ ^ of pthe

& k ¿ t t ó ; p p n $ $ € , 1 > é ^ ¿ o c ^ * f d i / \ ^ c l ^ n w t a | ? ¿ \ iregíqídittf epeeifio eêrintent«' #tióbi*o«ld be performed to rwurfi

1 . , < ."'.' \0-

-V. -'., r >•.'

/ ' Y ^ ' . A . ' i ; . ; r ' j . , . . „ • > ; . , ] ; > f c / j i ^ K ^ - \ (-;1

i-:,.''r;- « ^ Y , ;'- „ • • : ' , « ' . _ _ "

. '••. V"'l

-:?. S .-'S-i'.X

::h: •••*

. °385a. ; Kbvacio,.; E C e t a li , " • - , > < - ""

-JPAST BREEDER'' " : * ' " V " / ' ' V ^ " ' " '"V ' > ''"•' '/' "'"

. . . -The basic- s t r u c t u r a l '.material i s the."-'primary.- siodium syatian.jp.f > tl;e;., ;; '; "β^xicojermi Fast BreedfeT Reactor; (EFPBR) i s ; a i i s t e n i t i o , s t a i n í e s á ;; ^

' ' s t e e l . . Where s t r eng th proper t ies" perfflit., .^type 304 a ta in less ; . : s tee l "",•(' • ;;'-Kae.";:%een';f.-aeéd*''.- ôr' comporieiits" r e q u i r i n g high"err s t r e n g t h s f ^ p e s 316,; 321°:andv347 have been used» 'Hie in te rmedia te hât-exchangers- (ánd i

• bas ic p i p i n g of the secondary system ,is"also.* qf'-typeT,'.3O4 s t a i n l e s s' s t ee i» ". The s t ean genera tors ' a ré láaáé of r a 2 l / 4 $ Mo lo#<-aíjlqy s t ee l»g / $ jqy••Stress cor ros ión crátclcing of the áteamigeneraíájr -tubiiig.has beenobserved and has been r e l a t e d tpîhépleánin^prQcAdiufeUSfd»p i p ^ p A f f

eí s ta inless s teel i s susceptible to self-welding ánd; t

I -galling irbênîn intimat'e '-conjfettó-t • wi-th iftf elf,,. • This,. its particularly. so, \.- .in.a sodium .environmeht., ás .á ' reáuíf , ônside^blé; effort has been"•

;:?; dévotéd :ío-evalíüatión 5bf variousi surfápé treajtments pr coatings ; "•-«that •catt^be applied to' the stainless' 'steel 's to,prevent galling in both

-,-,•.••'. i n e r t atiaosphéres'and'in sodium. In general, i t , was found that the*'¿. JiárderéEiatériáls-áuch|,iás chromium,plate, ni t r ided surfaces^ and J '

;"• hard-fabe coalings gfcve superior resis tance .to galling under most - *^--conditions. Kitrijiing'of the staí i i iéss s teel ha.s been used» rather

-/ extensively'with good sueeess..,'%!IThe;orie exception has been;. on the =• ••5 .application to dummy subassembly nozales. Here^.it i s believed

-- that the nitridi 'ng was substandard with respect ' to processing-and,•^Γ':•;."that higher-than-ahticipated loads were"encountered during non- " -

.., nuclear tes t ing *, as á resu l t , the n i t r ide- layer waB^subject to .. -%: . epall lng. In a l l other appricatitiiw^ tíié n i t r i de "wa9°;fq}ind t a be '-.•" '"'""'".' a d h e r e n t . ^ ' , „ ,"r --- ' t ".;, . '. • " '.••". - * " v . • • ' '*. ' _• -''.""' ' ,."• " •—

366 . BONUS BOILING WATER NUCLEAR SUPERHEAT REACTOR PROJECT-. TASK FORCE>R* ON CHLdRI-DE STRESS CORROSIÓN OF AUSTENETIC STAINLESS STEELV '..

' - . • • • • . / ' • / " • • • • ' • • = ' " • *-''] r ? ; -' • ' " • >-' • " ; - . ' ' " - . . " „ ' & ' ' - ° . : - * • V '

- : . 1 9 6 2 . = * : • • • " * ••-' „ . , " • " * • • . ? ' , • , . . . * ; . - • " * : - / ' - .

.387. COOLAHT '"AND" CORROSION.

.•"'V*' ':! •ZΓ'"' - ' . i .H"" '

, o ^ °S

t * a p * t * t u i « jr**aia''from a boil'i'ng-water" r e a c t o r 'ê ing

. : : ' ; - • ; - • - • • : , . - • _ . • / • • • - . . . / .

Incoloy 800 fuel cladding corrosion and üjOoaliaed corrosión of , , ;' type-304 SS. and nickel-base alloys in superheated siesp ¡were studied»Oxidation products'dis.trilMitions'during expo.asure to superheatedsteam were studied for 300-series SS and nio^l-tase alleifs with andwithout heat transfer» The development "of a .ti^gital-readout*programmed1 dissolved gas analyzer is.reported. The EYESR chemistryprograms are described* .,••.-.

J ..•_•

AUTHOR IUBEX

Akshentseva, A PAktiebolag, S JAlekseenke, M'FAllio, R JAadreev, Yu VAráviñdakshah, C •Armijo J SArmijo, J SAsawaj M 'Ashbaugli, W G

Bebakov, A ABackensto, E B

• Badart, ABade, JBailey, S 0Baker, H RBalezin, B ABarnhartt, SBarnwell, Y LBarüartt, S

; Bates, E FBates j J' FBaúltóñ, JBaunél, A -Beok, f'HBéier, E•Bel'lot,' J . -Belous,. V mBergen, C RBerggreen, JBérry, W Í EBiefer:,;, <?;. jBireheri, D , .

S3.J .

Bqllant, u . .'.: Bond, ,A P :"/•;

Booth j *G 0"Bofgst&dt, H 1.Bbüfrantj • J.:•>•••:

Bovíe.r'sock, 'R YBóydí W,K ••/;:•':Brá"bers,;MvJBrauhs^' E^ •Brenner ¿.'P;' B é t V S ' ¿{;'Bryani, R E,\Btíkt E R

250'12

. 29?3

, 4335,56

8,9,1011121314 ,15,16358171819 • "'20 ,21>22,23 ;42.-24 -. .

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359 ', .." '• 40,41".'.43,138,139

•:44 ,'•';• f.. 4 5 ^ 4 6 -•••

. 4 7 --•.•

4 8 ;v " ",' •

Garter, C SCasle, I BChaudron, GCheng, C F. Chikunov, Y KChristopher, S SCibal, VClarke, P EClevinger, G S

Cochran, R WCo lemán, E GCook, E W J"r.,Copson, H RCoriou, H,Córioií., N0ouperf A SCox, T BCracknel1, ACreak, G ECrossley, P A

Da Cunlia Bel o, MDavis, J ADaviea, M Ji>,enliard, E E. Jr.,Desestret, A¿és.pie, A RSeVries, GDodd, R ADouglass,, D LDuñcan, R NDundas, H JEckél, J P

.Economy, G ,Eds iron, J O;Eng3Íish,, J IEváná,:"P R VFairnian,-L .Peld^an,'-M- S";' . .Peri^ií, R IT ''Fersmán, LAFoJcinl M,N

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AcetatesAdsorption'Aerospace'Aging .Alkaline earthhalidesAmmonia PlantAmmonium chlorideAnions .Aqueous mediaAutoclaves

BibliographyBoric acid

Chlorides

\,'Chemical composi-tionChemical, IndustryCarbonCalsium chlorideCold GoxCold-rqllingCold workingContaminationCoolant .Corrosion. ..•"•;••inhibitorsCorrosion . . - -•>;.. resistance"

Corrosion testingCracking > 'Crack initiation' •'Crack propagationCreepCrystal growthCrystalibgraphy

DeformationDelaying

KEYWORD

3 1 1 •" ' ''•'

218,333276 •97

339319

218215260 '

93,113,225

177

12,31,48,50,51,52,71,91,105,117,118,165,272,242,'299,315,357,

386, .

2.742 6 4 . •

1361319193129,322,3263387

214.

1,61,71,83,84,106,196, .212,231,247,248,250,251,252,2.78,309-,310,347,365 :88,150 ...185,202 '.,--.' ''2Í9.-: • ' •-• ,

89,182-' '-•-- •243,340- -•363197,201 ;.••'•. '.

345 ' ;" ."' :-".'.2 1 4 : . - ' • , - • •

IHDEX*

DislocationsElectrochemicalEffects

ElectrolysisElectron microscopyBnbrittlement

FailiireFatigue

FerritesFlavrsFlow resistanceFractene -FuelcladdingFuel elements

Heat exchangersHeat fluxHeat transferHeat treatmentHeavy waterHigh purityHigh strength steelsHydrogen

Induction periodInhibitorsIntercrystalline

••£• corrosión

Intergranularooxrmion

. \ Ions'-'-. Irradiation_ r-\ Lithium

•¿} • Magnesium chloride

- -Manganese' Martenstitic steels.

367

85,89,184,228,229,233,240,244,245,337325285,29037,100,158,244,245,282,333,36195,198,343,369149, 232,259,•1 D O 1 A t\Io<s,o4038,39J

18034712744384

223243277,375278, ¿50,279,343222222,238346,254,318,32037,185,202,244,245,282,292,301,302,316,317

7 7

32430,360

110,190,340

58,5,133,211,215,334,336,36210886

• • 9 2 • .

8,9,40,55,61,70,84r85,i29,i30,131>i62,280,337,358.""...335, • .;.

149,305,307,308; Meohanical properties178,348; Microtopology 257,258; Molybdenum ••;.,' 90 , i .

-• 152..-

NitratesIfitrogen

OrderingOrganic liquids ... .. ,Oxygen ' " . " >'"OH effects.PliysphatesPhosphorusPoisons.Pqtentiostatic measurementsPreinuner3ionPressurePittingPressure vesselsProtective cratingsPulsating LoadPurity ••Radioactive Tracers.Reactor materialsReactors 'Shipping port power stationSilicon \SodiumSodium chlorideSolution chemistryStacking faultsSteapr • ' ~\Straining.Stress rupture'Structure .• 'Structural iaeterialsSulfides ' ..- ' • '' -: .Sulfuric acidSurface • '. .•;.

•Surface chromizatiori- •Surfa,ce treatment .Temperature ' r * - •-

Transgranular corrosion. ,Type 302 . ' -'" .Type 304

Yielding

52,311¿344.,,13-^2,63»64,65,66,67,68,78,79,80,81,. 98,102,103*104,162,179,230,351224 •

219 - . ,117,334,33:6111168162,23033232032472.122,218,187217113,1163SÍ192210113 '. ' .171,206,207,321,366,385327' '"90^5352436,54,128,176 .235 - . .94-, 224121,171,249 •• - - • • . •-.-

NL22S •2 4 3 • : . . . - .2 1 2 . .62,-96161,314 - • ' .

6,106,1286 9 , 7 0 • .'. • •

12 • -.-2 4 7 , 2 4 8 , 3 5 9 ' . •.•-•-•>.: z

Ó. 5,12,^5,205:,i34-,142,143,156,176,178,,190,107,208,243,345,368,375 \. 2 3 8 .. ' : ; ' . ' :• , ; -,/..t- . .. •

-lf t124'- ' ". •••-',''•.'.

15,58,72,117,142,143,166,190,204,205,208,334,336,359,366,368 ... - • ,• ' ,.2 4 1 '- . ' • . . , . - • ' • •'-•••. •••• . . • •

- • - 1 5 3 -

STRESS CORROSION CRACKING STAINLESS STEELS A ...

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