Permanent joints (Assemblages permanents ) _Course - ISET ...

Higher Institute of Technological Studies of Gafsa-Tunisia

Department of Mechanical Engineering

Applied License in Mechanical Engineering

Metallic Construction

Integrated course: Permanent joints

Prepared by: Rached Nciri Technologist, Doctor Engineer

Level 2- Applied license in Mechanical Engineering-Metallic Construction

Academic year: 2020-2021

Foreword

The content of this material consists of a course entitled “Permanent

joints”. It is addressed to the students preparing the Applied License in

Mechanical Engineering-Metallic Construction, taught in the Department of

Mechanical Engineering of the Higher Institute of Technological Studies of

Gafsa-Tunisia. More globally, all students who receive a technological

education in Mechanical Engineering can benefit from this material. This is a

first version that can be improved and updated whenever required.

PERMANENT JOINTS

COURSE

• Domain : Mechanical Engineering-Metallic Construction

• Level : L2-CME2-S32

• Prerequisites: Level 1-Applied License in Mechanical

Engineering.

• Number of hours: 21 hours.

• Goals :

- To know the main technical details of the conventional

welding processes (SMAW, GMAW and GTAW).

- To know the main technical details of the liquid state welding

processes (High energy welding, Resistance welding and

Laser-hybrid welding).

- To know the main technical details of the solid state welding

processes (Friction welding, Ultrasonic welding, Diffusion

welding, Explosion welding).

- To master the welding symbols (based on the AWS

standards).

- To master the design resistance/sizing of fillet welds (based

on the Eurocode 3 standards).

- To know the main technical details of the principal types of

permanent joints other than welding.

Table of contents

CHAPTER 1. CONVENTIONAL WELDING PROCESSES. ....................................... 4

1. Shielded Metal Arc Welding (SMAW) .......................................................................... 4

1.1. Principle of the SMAW .............................................................................................. 4

1.2. Types of welding position and joint............................................................................ 5

1.3. Coated electrode.......................................................................................................... 6

1.4. Types of coating .......................................................................................................... 7

1.5. Parameters and aspects of the SMAW ........................................................................ 8

2. Gas Metal Arc Welding (GMAW) ............................................................................... 10

2.1. Principle of the GMAW ............................................................................................ 10

2.2. Parameters of the GMAW ........................................................................................ 11

3. GMAW modes of metal transfer .................................................................................. 13

4. Gas Tungsten Arc Welding (GTAW) .......................................................................... 14

4.1. Principle of the GTAW ............................................................................................. 14

4.2. GTAW current .......................................................................................................... 15

4.3. GTAW electrode ....................................................................................................... 16

4.4. GTAW nozzle ........................................................................................................... 16

4.5. Parameters of the GTAW.......................................................................................... 17

5. Safety instructions ......................................................................................................... 19

6. References ....................................................................................................................... 19

CHAPTER 2. LIQUID STATE WELDING PROCESSES. .......................................... 22

1. High energy welding ...................................................................................................... 22

1.1. Plasma Arc Welding (PAW) ..................................................................................... 22

1.1.1. Principle of Plasma Arc Welding ....................................................................... 22

1.1.2. Types of Plasma Arc Welding ........................................................................... 22

1.1.3. Advantages/Limitations of Plasma Arc Welding ............................................... 25

1.2. Electron Beam Welding (EBW) ............................................................................... 25

1.2.1. Principle of Electron Beam Welding ................................................................. 25

1.2.2. Advantages/Limitations of electron beam welding ............................................ 25

1.3. Laser beam welding (LBW)...................................................................................... 26

1.3.1. Principle of Laser Beam Welding ...................................................................... 26

1.3.2. Advantages/Limitations of Laser Beam Welding .............................................. 27

2. Resistance Welding ........................................................................................................ 28

2.1. Spot welding ............................................................................................................. 28

2.1.1. Principle of spot welding.................................................................................... 28

2.1.2. Advantages/Limitations of spot welding ........................................................... 28

2.2. Projection welding .................................................................................................... 30

2.2.1. Principle of projection welding .......................................................................... 30

2.2.2. Advantages/Limitations of projection welding .................................................. 31

2.3. Seam welding ............................................................................................................ 32

2.3.1. Principle of seam welding .................................................................................. 32

2.3.2. Advantages/Limitations of seam welding .......................................................... 32

2.4. Butt welding .............................................................................................................. 33

2.4.1. Principle of butt welding .................................................................................... 33

2.4.2. Advantages/Limitations of butt welding ............................................................ 33

3. Laser-hybrid welding .................................................................................................... 34

3.1. Principle of Laser-hybrid welding ............................................................................ 34

3.1.1. Advantages/Limitations of Laser-hybrid welding ............................................. 34

4. References ....................................................................................................................... 36

CHAPTER 3. SOLID STATE WELDING PROCESSES. ............................................ 37

1. Friction Welding (FRW) process ................................................................................. 37

1.1. Principle of the Friction Welding (FRW) process .................................................... 37

1.2. Advantages/Limitations of the Friction Welding (FRW) process ............................ 37

2. Ultrasonic Welding (USW) process.............................................................................. 40

2.1. Principle of the Ultrasonic Welding (USW) process ................................................ 40

2.2. Advantages/Limitations of the Ultrasonic Welding (USW) process ........................ 41

3. Diffusion Welding (DW) ............................................................................................... 41

3.1. Principle of the Diffusion Welding (DW) process ................................................... 41

3.2. Advantages/Limitations of the Diffusion Welding (DW) process ........................... 42

4. Explosion Welding (EXW) ............................................................................................ 43

4.1. Principle of the Explosion Welding (EXW) process ................................................ 43

4.2. Advantages/Limitations of the Explosion Welding (EXW) process ........................ 44

5. References ....................................................................................................................... 44

CHAPTER 4. WELDING SYMBOLS. ........................................................................... 46

1. Welds types ..................................................................................................................... 46

1.1. Fillet weld ................................................................................................................. 46

1.2. Groove weld .............................................................................................................. 46

1.3. Surfacing weld .......................................................................................................... 47

1.4. Plug weld .................................................................................................................. 47

1.5. Slot weld ................................................................................................................... 48

1.6. Flash weld ................................................................................................................. 48

1.7. Seam weld ................................................................................................................. 49

1.8. Spot weld .................................................................................................................. 49

1.9. Upset weld ................................................................................................................ 49

2. Welding symbols chart .................................................................................................. 50

3. Basic welding symbol examples .................................................................................... 51

3.1. Welding symbol for fillet welds ............................................................................... 51

3.1.1. Location .............................................................................................................. 51

3.1.2. Size ..................................................................................................................... 51

3.1.3. Pitch .................................................................................................................... 52

3.1.4. All around ........................................................................................................... 52

3.2. Groove welds ............................................................................................................ 53

3.2.1. Types .................................................................................................................. 53

3.2.2. Size ..................................................................................................................... 54

4. Specific welding symbol examples................................................................................ 54

4.1. Back and backing welds............................................................................................ 54

4.2. Weld contours and finishing of welds ...................................................................... 55

5. References ....................................................................................................................... 56

CHAPTER 5. RESISTANCE/SIZING OF WELD BEADS .......................................... 57

1. Weld constituent elements ............................................................................................ 57

1.1. Effective throat thickness .......................................................................................... 57

1.2. Useful length ............................................................................................................. 57

1.3. Effective area ............................................................................................................ 58

2. Principal types of loads ................................................................................................. 58

2.1. Weld subjected to tensile .......................................................................................... 59

2.2. Weld subjected to pure shear .................................................................................... 59

2.3. Weld subjected to tensile and shear .......................................................................... 59

3. Stresses within welds ..................................................................................................... 60

4. Practical exercises .......................................................................................................... 62

4.1. Directional method for design resistance of fillet weld/Weld sizing ........................ 62

4.1.1. Weld subjected to pure shear ............................................................................. 62

4.1.2. Weld subjected to tensile and shear ................................................................... 64

4.2. Simplified method for design resistance of fillet weld ............................................. 66

5. References ....................................................................................................................... 67

CHAPTER 6. OTHER TYPES OF PERMANENT JOINTS........................................ 68

1. Brazing process .............................................................................................................. 68

1.1. Principle of the brazing process ................................................................................ 68

1.2. Industrial applications of the brazing process ........................................................... 70

2. Riveting process ............................................................................................................. 71

2.1. Principle of the riveting process ............................................................................... 71

2.2. Industrial applications of the riveting process .......................................................... 73

3. Mechanical crimping process ....................................................................................... 73

3.1. Principle of the crimping process ............................................................................. 73

3.2. Industrial applications of the crimping process ........................................................ 73

4. References ....................................................................................................................... 74

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Conventional welding processes

4 Rached Nciri, D. Eng., Technologist

Chapter 1. Conventional welding processes.

In order to carry out permanent joints in weldments, a technological variety of

conventional welding processes is provided. Among this welding variety, the most used types

of welding are:

• Shielded Metal Arc Welding (SMAW).

• Gas Metal Arc Welding (GMAW).

• Gas Tungsten Arc Welding (GTAW).

1. Shielded Metal Arc Welding (SMAW)

1.1. Principle of the SMAW

The principle of the SMAW [1.1,1.2] (and all arc welding processes) is based on the

production of heat from electrical energy by the Joule effect. The produced heat is used to

fuse the edges of the workpieces to be joined. The arc welding power source produces a high

electrical current (AC or DC current) that will pass through both electrode (connected to one

terminal of the power source) and workpiece (connected to the other terminal of the power

source). Electric cables, electrode holder and workpiece connector (clamp) are used to ensure

the electrical circuit. When the electrode is close enough to the workpiece (almost 2 mm to 3

mm), the high electrical current will be able to pass through the air gap between the electrode

and the workpiece. The air, initially considered as a highly insulating medium, becomes

conductor under the influence of the high electrical current: an electric arc is created. This

electric arc is simply the revelation of the passage of electric current through the air. The air

crossed by the electric current releases heat thanks to the Joule effect. Hence, the fusion of the

workpiece (base metal) edges and the coated electrode (filler metal) is created: the weld bead

is created. Figure 1.1 [1.3] depicts the different components of a SMAW machine. Figure 1.2

[1.4] depicts the SMAW welding phenomena.



Figure 1.1. Components of a SMAW machine.

Figure 1.2. SMAW welding phenomena.

1.2. Types of welding position and joint

Figure 1.3 [1.7] depicts the different welding positions and joints.



Figure 1.3. Welding positions and joints.

1.3. Coated electrode

The SMAW coated electrode consists of 2 parts as depicted by Figure 1.4.

Figure 1.4. SMAW coated electrode.

• Electrode: it is a metallic rod intended to conduct the electric current. It is generally of

the same nature as that of the workpiece.



• Coating: it is an adhesive chemical composition that covers the electrode, and it is

intended to play 3 principal roles [1.2]:

o Metallurgical roles: protection of the molten weld pool against Oxygen and

Nitrogen form the ambient air, harmful to the mechanical properties of the

weld bead. This protection is ensured by producing a protective layer, called a

slag, which will envelop the molten weld bead.

o Electrical roles: facilitating the strike (ignition) of the electric arc and maintain

its stability.

o Mechanical roles:

- Channeling and concentration of the electric arc.

- Improvement of the mechanical properties of the weld bead.

1.4. Types of coating

Table 1.1 summarizes the most used types of coating [1.5,1.6] as well as their chemical

characteristics, welding applications and eventual precautions to consider.

Table 1.1. Coating typology and applications.

Type of

coating

Chemical

characteristics Welding applications Precautions

Basic (B) High proportion of calcium carbonate and fluoride

- Limestone slag (desulfurizing effect) -Suitable for welding ferritic steels - Reduced risk of hot cracking of the deposited metal - Direct current / reverse polarity (electrode at terminal +)

Steaming at 350 ° for 2 hours. (unless otherwise specified by the supplier)

Cellulosic (C)

High proportion of cellulose

- Little slag -Suitable for rapid welding in downward position - Improved penetration - Direct current / reverse polarity (electrode at terminal +)

Open circuit voltage ≥60V

Rutile (R) High proportion of titanium dioxide

- Slag is easily eliminated -Suitable for welding in all positions -Metal deposited with good

No special precautions



mechanical characteristics when steels have limited carbon and sulfur contents - Direct / alternating current

Acid (A) High proportion of acidic matter

- Very fluid and abundant slag - Suitable for flat, horizontal (Corner joint and T-joint) welding. Not suitable for vertical (Up and down) and overhead welding. - Requires good weldability of the base metal otherwise joint sensitive to hot cracking.

No special precautions

1.5. Parameters and aspects of the SMAW

There are several parameters for SMAW:

• Diameter of the electrode.

The appropriate diameter of the electrode eφ is determined according to the

thickness t of the workpiece [1.8]. Comply with the indications on the supplier's

technical data sheets or use the Formula 1.1.

te

≤φ (1.1)

• Intensity of the electrical current.

The intensity of the welding current I depends mainly on the diameter of the

electrodee

φ [1.1,1.8]. Comply with the indications on the supplier's technical data

sheets or use the Formula 1.2 for butt joint:

)(I)mm(

e

)A(

150 −×= φ (1.2)

For corner joint, the value of the current intensity is reduced by 20%.

For T-joint, the value of the current is increased by 20%.

• Travel speed (speed of the movement of the electrode during the welding operation).

• Distance between the electrode and the workpiece (air gap dimension).



• Welding positions (flat, horizontal (Corner joint and T-joint) and vertical: up and

down).

• Welding polarity.

When the Direct Current (DC) is used, the SMAW welding polarity may be 2 types [1.9]:

o Straight polarity: it is a direct current with a negatively charged electrode and

a positively charged workpiece (DCEN). With a straight polarity, 2/3rd of the

arc heat is generated near the workpiece while the remaining 1/3rd is generated

at the electrode tip. The melting rate of the workpiece increases and the filler

deposition rate of the electrode decreases. The width of the weld bead is

decreased while the penetration (depth) is increased.

o Reverse polarity: it is a direct current with a positively charged electrode and a

negatively charged workpiece (DCEP). With a reverse polarity, 2/3rd of the arc

heat is generated at the electrode tip while the remaining 1/3rd is generated

near the workpiece. The melting rate of the electrode increases and the filler

deposition rate of the electrode increases. The width of the weld bead is

increased while the penetration is decreased.

It is to note that when the alternating current is used, the polarity will change almost 100

times per second. An even heat distribution is created, so, between the electrode and the

workpiece. Thus, a balance between bead penetration and electrode filler deposition rate

(bead width) is provided.

The variation of these parameters mainly affects the following welding aspects:

• Size and shape of the weld bead.

• Penetration of the filler metal within the base metal.

• Fusibility of the coated electrode.

The principal weld bead aspects are depicted by the Figure 1.5.



Figure 1.5. Weld bead aspects.

2. Gas Metal Arc Welding (GMAW)

2.1. Principle of the GMAW

The GMAW process, also called MIG/MAG (Metal Inert Gas/Metal Active Gas), is part of

the arc welding family. It consists in establishing, under gaseous protection injected

continuously (against Oxygen and Nitrogen in the air), an electric arc between the tip of an

electrode (generally bare copper conductive wire, unwinding at a predetermined speed) and

the workpiece. When the shielding gas does not react with the molten weld bead, it is called

inert. Argon and the mixture between Argon and Helium are neutral gases. When the

shielding gas does not react with the molten weld bead, it is qualified by active. The mixture

between carbon dioxide, hydrogen and argon (in varying proportions depending on the nature

of the metal to be welded) are active gases. Figure 1.6 [1.10] depicts the principal components

of a GMAW machine. Figure 1.7 depicts the components of a typical GMAW torch (gun)

[1.11]. Figure 1.8 [1.10] depicts the GMAW welding phenomena.

Figure 1.6. Principal components of a GMAW machine.



Figure 1.7. GMAW torch (gun).

Figure 1.8. GMAW welding phenomena.

2.2. Parameters of the GMAW

The GMAW parameters [1.12] are the quantities which influence the aspects of GMAW

weld bead: size and shape as well as the penetration of the weld bead into the base metal. The

GMAW parameters are mainly:

• Voltage

• Wire feed speed (the intensity of the welding current is proportional to the wire feed

speed)

• Wire diameter

• Distance between torch and workpiece

• Torch movement speed

• Torch position



The manufacturer of the GMAW machine generally provides the GMAW parameters

depending on the thickness of the part to be welded (Table 1.2) [1.13].

Table 1.2. GMAW parameters for a SAFMIG 400 BL welding machine. T

hic

kn

ess

(mm

)

Po

siti

on

Wir

e d

iam

eter

(mm

)

Volt

age

(V)

Wir

e fe

ed s

pee

d

(m/m

in)

Cu

rren

t

Inte

nsi

ty (

A)

Sw

itch

po

siti

on

Ma

teri

al

Gas

Wir

e m

ate

rial

10/10 30/10

Fillet

0.8 16 19

2.8 7.8

55 125

A-1 C-2

Ste

el

AT

AL

7

0S

15/10

Butt

0.8 17.5 5.4 90 B-2

15/10 30/10 80/10

Fillet

1 16 18 28

3.1 5.5

10.5

90 135 190

A-1 B-4 E-3

15/10

Butt

1 16 3 80 A-2

15/10 30/10 80/10

Fillet

1.2 14.5 17 29

3 3.8 8.5

140 180 275

A-1 B-1 E-1

20/10

Butt

1.2 15 2.8 115 A-2

40/10 80/10

Fillet

1.2 16 27

3.7 7.8

110 220

A-4 E-2 S

teel

A

TA

L

SD

20

0

30/10

Butt

1 16 11.3 105 A-4

A-L

A

rgo

n

Ner

tali

c 3

0

20/10 30/10 60/10

Fillet

1 15 16 26

9.6 13

21.5

100 130 210

A-1 A-4 D-2



Th

ick

nes

s (m

m)

Po

siti

on

Wir

e d

iam

eter

(mm

)

Volt

age

(V)

Wir

e fe

ed s

pee

d

(m/m

in)

Cu

rren

t

Inte

nsi

ty (

A)

Sw

itch

po

siti

on

Ma

teri

al

Gas

Wir

e m

ate

rial

30/10

Butt

1.2 16 8.9 130 A-3

A-L

A

rgo

n

Ner

tali

c 3

0

20/10 60/10

Fillet

1.2 15 27

7.4 16.5

110 275

A-1 D-4

30/10 80/10

Butt

1.6 15 27

5.2 10

130 260

A-2 D-4

10/10 15/10 50/10 80/10

Fillet

1

15.5 16 21 25

2.6 3

9.3 9.7

60 72

165 180

A-1 A-1 C-4 C-4

Sta

inle

ss s

teel

N

ox

alic

12

N

erta

lic

50

20/10

Butt

1 17 5.1 100 B-1

15/10 30/10 50/10 80/10

Fillet

1.2

16 17 20 29

2.7 4.3 7.5

10.5

80 140 200 245

A-1 B-2 C-4 E-4

15/10

Butt

1.2 16 2.6 75 A-1

30/10 80/10

Fillet

1.6 16

25.5 2.5 3.1

165 240

B-2 D-2

3. GMAW modes of metal transfer

Table 1.3 summarizes the principal GMAW modes of metal transfer and their

technological attributes (current intensity, workpiece thickness and welding position) [1.14].



Table 1.3. Principal modes of metal transfer and their attributes for GMAW.

Metal transfer

modes

Current

intensity

Thickness of

workpiece Position

Short-circuit transfer 30A-200A Thin workpiece Any position (Flat,

Horizontal, Vertical and Overhead) Axial spray transfer 200A-400A Thick workpiece Flat and horizonal

4. Gas Tungsten Arc Welding (GTAW)

4.1. Principle of the GTAW

The GTAW process, also called TIG (Tungsten Inert Gas), is part of the arc welding

family. It consists in establishing, under gaseous protection injected continuously (against

Oxygen and Nitrogen in the air), an electric arc between the tip of a non-fusible Tungsten

electrode and the workpiece. Argon and the mixture of Argon and Helium are the neutral

gases used in TIG welding. The filler metal (of the same nature as the base metal) is added

separately by a filler rod. Figure 1.9 [1.15] depicts the principal components of a GTAW

machine. Figure 1.10 depicts the components of a typical GTAW torch (gun) [1.16].

Figure 1.11 [1.17] depicts the GTAW welding phenomena.

Figure 1.9. Principal components of a GTAW machine.



Figure 1.10. GTAW torch (gun).

Figure 1.11. GTAW welding phenomena.

4.2. GTAW current

Two types of current are used:

• Direct current: The welding is carried out with an electrode connected to terminal (-)

and a workpiece connected to terminal (+). The direct current is used for welding

structural steels and stainless steels and also for copper alloys.

• Alternating current: has the particularity of being able to destroy the surface and

insulating oxide layer. It is used, as well, for welding aluminum alloys.



4.3. GTAW electrode

There is a technological variety of Tungsten electrodes [1.18,1.19] for the GTAW process.

Five principal type of tungsten electrode are summarized by the Table 1.4.

Table 1.4. Principal GTAW electrodes.

GTAW electrode type Color Current Welded material

Pure tungsten electrode Green AC Aluminum alloys 0.8% Tungsten Zirconium

electrode White AC Aluminum alloys

2% cerium tungsten electrode

Gray DC Structural steels, stainless steels and nickel

and titanium alloys 1.5% Tungsten-Lanthanum

electrode Yellow AC-DC Structural steels and stainless steels

2% thoriated tungsten electrode*

*Be careful, Thorium is

radioactive!

Red DC Structural steels and stainless steels

4.4. GTAW nozzle

The nozzles ensure a continuous jet of shielding gas. They have an internal diameter which

varies between 6 mm and 20 mm. The main materials of the GTAW nozzles as well as and

their principal mechanical and thermal characteristics [1.20] are summarized by the Table 1.5.

Table 1.5. Principal GTAW electrodes.

GTAW nozzle material Color Mechanical and thermal characteristics

Ceramic Dark pink Poorly resistant to mechanical shocks Resists thermal shock well

Alumina Pink Fairly resistant to mechanical shocks Poorly resistant to thermal shock

Silicon Nitride Drak gray Resists mechanical shocks well Resists thermal shock well

Pyrex Transparent Poorly resistant to mechanical shocks Resists thermal shock well

(offers good visibility)



4.5. Parameters of the GTAW

The GTAW parameters are the quantities that influence aspects of GTAW weld bead: size

and shape as well as the penetration of the weld bead into the base metal. The main GTAW

parameters are [1.18]:

• Current intensity

• Diameter of the electrode

• Nozzle diameter

• Diameter of the filler metal

• Shielding gas flow

• Torch movement speed

The manufacturer of the GTAW machine generally provides the GTAW parameters based

on the thickness of the workpiece (Table 1.6) [1.21].

Table 1.6. GTAW parameters.

Non alloy steel, Low-alloy steel and stainless steels

Electrode 2% thoriated tungsten electrode; 2% cerium tungsten

electrode; 1.5% Tungsten-Lanthanum electrode

Shielding gas Pure Argon

Current type DC (Electrode connected to the negative terminal)

Welding position Flat (for other welding positions reduce the intensity by 10

to 20%)

Workpiece

thickness(mm)

Electrode

diameter

(mm)

Filler

metal

diameter

(mm)

Current

intensity

(A)

Nozzle

diameter

(mm)

Gas flow

rate

(l/min)

Welding

speed

(cm/min)

0.6 1 - 1

10-25 6 4 20-40

0.8 1 - 1

15-35 6 4 30-40

1 1.6 1.2 25-65 9 4 25-40

1.5 1.6 1.2 1.6

45-95 9 5 20-45

2 2 1.6 2

60-110 11 5 15-30

2.5 2 2

2.5 90-130 11 5 15-30

3 2.4 2 100-150 13 6 15-30



2.5 4 2.4 3 120-200 13 6 10-25

5 3 3 4

150-250 13 6 10-25

6 4 4 200-300 15 8 10-20 Aluminium et aluminum alloys

Electrode Pure Tunstene

Shielding gas Pure Argon ; Argon / helium mixture

Current type AC (High frequency stabilized)


to 20%)

Workpiece

thickness(mm)

Electrode

diameter

(mm)

Filler

metal

diameter

(mm)

Current

intensity

(A)

Nozzle

diameter

(mm)

Gas flow

rate

(l/min)

Welding

speed

(cm/min)

1 1

1.6 1.6 30-55 9 7 20-25

1.5 1.6 1.6-2 60-80 9 7 20

2 2

2.4 2

2.5 70-120 11 7 15-20

2.5* 2.4 2.5-3 110-140 13 8 10-20

3* 2.4

3 140-160 13 8 10-15

4* 2.4 3

3 4

140-160 13 8 10-15

5* 3 4

4 150-190 15** 9 5-15

6* 4 4-5 180-240 19** 9 5-15 8* 5 5 200-300 19** 10 5

Cuivre désoxydulé

Electrode 2% thoriated tungsten electrode; 2% cerium tungsten

electrode; 1.5% Tungsten-Lanthanum electrode

Shielding gas Pure Argon

Current type DC (Electrode connected to the negative terminal)


to 20%)

Workpiece

thickness(mm)

Electrode

diameter

(mm)

Filler

metal

diameter

(mm)

Current

intensity

(A)

Nozzle

diameter

(mm)

Gas flow

rate

(l/min)

Welding

speed

(cm/min)

1 1.6 1.6 60-110 11 5 35 1.5 2 1.6-2 120-130 13 5 35 2 2 2 120-170 13 5 30

2.5* 2.4 2 170-200 15 5 30 3* 3 3 170-230 19 6 30 4* 3 3 200-270 19** 7 25 5* 3 3 220-300 19** 7 25 6* 4 3 280-350 19** 8 20 8* 4 3 280-350 19** 10 15



4

12* 5 4 5

400-500 19** 12 10

* GMAW weldable if the GMAW quality is acceptable **The diffuser nozzle is recommended to limit the heating of the torch

5. Safety instructions

The welder must respect certain safety measures and use Personal and Collective

Protective Equipments (PPE and CPE) when he carries out arc welding (SAMW, GMAW and

GTAW). Table 1.7 summarizes the main risk phenomena as well as their corresponding safety

instructions [1.2,1.12,1.18].

Table 1.7. Safety precautions for arc welding.

Phenomenon Risks Safety instructions

Ultraviolet radiation Micro injuries in the eyes Radiation filter mounted on a mask or helmet

Released smoke

Intoxication by inhalation - Outdoor welding - Smoke extraction circuit in the workshop

Eye burns

Lung overload

Intense heat Hand burns Gants de sécurité Body burns Tablier en cuir

High electric current Electrocution - Checking the electrical circuit - Safety gloves.

6. References

[1.1] Houldcroft, P. T. (1973) [1967], "Chapter 3: Flux-Shielded Arc Welding". Welding Processes. Cambridge University Press. p. 23. ISBN 978-0-521-05341-9.

[1.2] Nciri Rached (2019), Atelier Procédés et Méthodes I-Soudage à l’arc avec électrode enrobée, Higher Institute of technological Studies of Gafsa-Tunisia, Digital courses, http://www.isetgf.rnu.tn/ENS/uploads/nciri_rached/AtelierProcedes_et_Methodes_I_TP_Rached_Nciri.pdf, Access date: 01/09/2020; 07:50 AM

[1.3]Welding321 (2018), Stick Welding, https://www.weldingis.com/smaw-stick-welding/, Access date: 08/23/2020; 11:42 AM

[1.4]U.S. Army (1967), Operators manual welding theory and application, Figure 5-26, p.72 at https://archive.org/details/TM9-237/page/n71/mode/2up, Access date: 01/09/2020; 07:40 AM



[1.5] The International Organization for Standardization (2016), ISO/TR 25901-4:2016(fr) Soudage et techniques connexes

[1.6] David, H. (2018), Les électrodes enrobées pour le soudage : leurs caractéristiques et leurs choix, https://www.soudeurs.com/site/les-electrodes-enrobees-pour-le-soudage-leurs-caracteristiques-et-leurs-choix-444/ , Access date: 08/23/2020; 12:40 PM

[1.7] Mechanical Engineering blog (2019), Welding position for plate (Figure), 1G, 2G, 3G, 4G, 5G, 6G, 1F, 2F, 3F, 4F pipe and plate welding position, http://www.mechanicalengineerblog.com/2019/03/30/1g-2g-5g-6g-pipe-welding-position/, Access date: 08/23/2020; 12:44 PM

[1.8] Centre National de Ressources-Structures Métalliques, Procédé soudage 111-Réglage de l’intensité de soudage (2012),

http://cnrsm.fr/c_ressources_cnrsm/5_divers/501_Dossier_machines/08_Fiches%20securite%20machines/Version_2/34_procede_111_catomatec_3058_09_04_2012.pdf, Access date: 08/23/2020; 12:49 PM

[1.9] Jeffus, L. (2016), Welding: Principles and Applications (8th ed.), Boston, MA 02210: Cengage Learning, ISBN 10: 1305494695, ISBN 13: 9781305494695

[1.10] Steven E. Hughes (2009), Chapter 5 - Welding Processes, A Quick Guide to Welding and Weld Inspection, Woodhead Publishing Series in Welding and Other Joining Technologies, 49-66, https://doi.org/10.1016/B978-1-84569-641-2.50005-2

[1.11] Jeff Grill (2019), MIG Welding (GMAW) Process Techniques & Tips, https://weldguru.com/mig-welding/, Access date: 10/10/2020; 03:21 PM

[1.12] Nciri Rached, Atelier Procédés et Méthodes I-Soudage MIG-MAG, Cours numériques, Institut Supérieur des Etudes Technologiques de Gafsa-Tunisie, http://www.isetgf.rnu.tn/ENS/uploads/nciri_rached/AtelierProcedes_et_Methodes_I_TP_Rached_Nciri.pdf

[1.13] SAF, Documentation techniques- SAFMIG 400BL

[1.14] Lycée Henri Darras, Liévin-France, Cours numériques, Soudage MIG, https://le-chaudronnier.pagesperso-orange.fr/Technologie/4procedeetmoyensassembl/soudageMIG.pdf

[1.15] http://knowwelding.weebly.com/gtaw.html, Access date: 11/10/2020; 08:57 AM

[1.16] U.S. Army Welding Manual

[1.17] Larry D. Smith (2001), The fundamentals of gas tungsten arc welding: Preparation, consumables, and equipment necessary for the process, https://www.thefabricator.com/thewelder/article/arcwelding/the-fundamentals-of-gas-tungsten-arc-welding--preparation-consumables-and-equipment-necessary-for-the-process

[1.18] Nciri Rached, Atelier Procédés et Méthodes I-Soudage TIG, Cours numériques, Institut Supérieur des Etudes Technologiques de Gafsa-Tunisie, http://www.isetgf.rnu.tn/ENS/uploads/nciri_rached/AtelierProcedes_et_Methodes_I_TP_Rached_Nciri.pdf

[1.19] Normes Françaises, NF EN ISO 6848: 2015



[1.20] CKWorldwide : The standard in TIG welding, Technical specifications for TIG Welding, http://www.ckworldwide.com/technical_specs.pdf

[1.21] Centre National de Ressources-Structures Métalliques, Procédé soudage 141-Paramètres de soudage TIG,

http://cnrsm.fr/c_ressources_cnrsm/5_divers/501_Dossier_machines/06_Dossier_Machine_temps_BTS_CRCI_2011/ressources/BTS%20complet%202.pdf

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Liquid state welding processes


Chapter 2. Liquid state welding processes.

The Liquid Stated Welding (LSW) processes are based in the fusion (liquid state) in order

to create welds. SMAW, GMAW and GTAW are considered, so, as conventional LSW

processes. However, other non-conventional LSW processes are more and less used in

industrial applications. Three principal technological varieties of non-conventional LSW

processes are distinguished:

• High energy welding: Plasma Arc Welding (PAW), Electron Beam Welding

(EBW) and Laser Beam Welding (LBW)

• Resistance welding: Spot welding, Projection welding, Seam Welding and Butt

welding

• Laser-hybrid welding (GMAW-augmented Laser, GTAW-augmented Laser and

PAW-augmented Laser)

1. High energy welding

1.1. Plasma Arc Welding (PAW)

1.1.1. Principle of Plasma Arc Welding

The Plasma Arc Welding (PAW) is a non-conventional welding process. It belongs to the

liquid state welding processes. The PAW consists in directing a hot jet of plasma (hot ionized

gases) towards a junction between metal workpieces in order to heat and then weld them by

fusion. The PAW process is similar to the GTAW except that the plasma is used, instead of

direct electric arc, to weld workpieces. A Tungsten electrode is used to heat an inert gas up to

25000°C-30000 °C in order to ionize it. It is to note that the PAW uses less current input

compared to the GTAW. Figure 2.1 depicts the principle of PAW [2.1]. Figure 2.2 depicts the

PAW machine [2.2]. Figure 2.3 depicts the details of the PAW torch [2.3].

1.1.2. Types of Plasma Arc Welding

Two types of Plasma Arc Welding are distinguished (Figure 2.4 [2.4]):

• Transferred Plasma Arc Welding: The direct current straight polarity (DCEN) is

used between the Tungsten electrode and the workpiece. The Tungsten electrode is

connected to the power source negative terminal while the workpiece is connected



to the positive one. Thus, the electric arc is established between the Tungsten

electrode and the workpiece. This will enhance the heating capacity of the welding

process. The transferred Plasma Arc Welding is adapted to thick workpieces

(especially thick sheet metals).

Figure 2.1. Principle of Plasma Arc Welding.

Figure 2.2. Plasma Arc Welding machine.



Figure 2.3. Plasma Arc Welding torch.

• Non-transferred Plasma Arc Welding: The direct current straight polarity (DCEN)

is used between the Tungsten electrode and the nozzle. The Tungsten electrode is

connected to the power source negative terminal while the nozzle is connected to

the positive one. Thus, the electric arc is established between the Tungsten

electrode and the nozzle within the PAW torch. This will enhance the ionization of

the gas within the torch. The torch will direct this ionized gas towards the

workpieces to be welded. The non-transferred Plasma Arc Welding is adapted to

thin workpieces (thin sheet metals).

Figure 2.4. Types of Plasma Arc Welding.



1.1.3. Advantages/Limitations of Plasma Arc Welding

The Plasma Arc Welding presents some principal advantages:

• High energy welding (high penetration. easy thick workpiece welding)

• High welding speed.

• Low power consumption.

• Electric arc stable and not affected by the distance between torch and workpiece.

The Plasma Arc Welding presents, also, some principal limitations:

• High cost (equipment and maintenance).

• High skill welder required.

• High level of radiated heat.

1.2. Electron Beam Welding (EBW)

1.2.1. Principle of Electron Beam Welding

The Electron Beam Welding (EBW) is a non-conventional welding process. It belongs to

the liquid state welding processes. The EBW consists in directing an electron beam towards a

junction between metal workpieces in order to heat and then weld them by fusion. The kinetic

energy of the electrons is converted into heat energy. The EBW process must be carried out in

a vacuum in order to avoid the loss of electron kinetic energy by collision of electrons with

the air particles. Figure 2.5 [2.5] depicts the principle of EBW. It is to note that no filler

material and no flux are used in EBW.

1.2.2. Advantages/Limitations of electron beam welding

The Electron Beam Welding presents some principal advantages:

• Both similar and dissimilar metal (with different melting temepratures) can be

welded.

• Suitable to weld hard materials.

• Low cost (No filler metal and no flux are used).



• High finish welding surface/Less welding defects.

Figure 2.5. Principle of Electron Beam Welding.

The Electron Beam Welding presents, also, some principal limitations:



• Limitation of the workpiece size range/ Welding cannot be carried out in site (due

to vacuum confined space).

1.3. Laser beam welding (LBW)

1.3.1. Principle of Laser Beam Welding

The Laser Beam Welding (LBW) is a non-conventional welding process. It belongs to the

liquid state welding processes. The LBW consists in directing a Laser beam towards a



junction between metal workpieces. The interaction between the laser and the workpiece

produces a large amount of heat. This laser beam will heat and then weld them by fusion. It is

to note that no filler material and no flux are used in LBW. Figure 2.6 [2.6] depicts the

principle of LBW.

Figure 2.6. Principle of Laser Beam Welding.

1.3.2. Advantages/Limitations of Laser Beam Welding

The Laser Beam Welding presents some principal advantages:

• Both similar and dissimilar metal can be welded/wide variety of materials can be

welded.

• High depth (penetration)-to-width ratio.



• Faster welding of relatively thick workpieces.

• Easy welding in narrow areas (areas that are not easy accessible).

• High welding quality.

• Well adapted to robotic automation.

• No X-rays.

The Laser Beam Welding presents, also, some principal limitations:


• High cooling rate of welds (cracks may occur in some metals).


• Welding thickness up to 19 mm no more.

• Low energy conversion rate (lower than 10%).

2. Resistance Welding

2.1. Spot welding

2.1.1. Principle of spot welding

Spot welding consists in establishing a high electric current (1000 A-5000 A with a low

voltage 2-12 V) passing through two sheet metals, placed under mechanical pressure. Two

electrodes ensure both the establishment of electric current and the application of mechanical

pressure. The two sheet metals will release, then, by Joule effect, heat all around the virtual

line of electric current flow. A melting point is thus created. After stopping the electric

current(after time cycle), this melting point will cool, solidify and turns into a weld spot. The

spot welding is well adapted to robotic automation. Figure 2.7 [2.7] (Partially modified

compared to the original reference for educational purpose) depicts the principle of the spot

welding. Figure 2.8 [2.8] depicts a conventional spot welding machine.

2.1.2. Advantages/Limitations of spot welding

The spot welding presents some principal advantages:



• High productivity.


• Less skill welder required.

• Relatively low equipment cost.

The spot welding presents, also, some principal limitations:

• Impossible welding of high thickness workpiece.

• High maintenance cost.

Figure 2.7. Principle of spot welding.

Fixed arm

Movable arm

Welding plates

Weld spot

High electric current



Figure 2.8. Spot welding machine.

2.2. Projection welding

2.2.1. Principle of projection welding

The projection welding is a modified technological form of spot welding that permits to

obtain multiple high strength welds even when sheet metals have not the same thickness. The

electrodes are flat. The two sheet metals to be welded are placed between the two flat

electrodes. A series of projections (nuggets) is fixed on the thickest sheet metal. The passage

of a high electric current combined with a mechanical pressure causes the fusion of these

projections and, then, the obtaining of multiple weld spots. Figure 2.9 [2.9] (Partially

modified compared to the original reference for educational purpose) depicts the principle of

the projection welding.



Figure 2.9. Principle of projection welding.

2.2.2. Advantages/Limitations of projection welding

The projection welding presents some principal advantages:

• Suitable to weld sheet metals with different thickness.

• Faster welding.

• Good weld quality.

• Long electrode life.

The projection welding presents, also, some principal limitations:

• Need to place projections on the sheet metal.

• High maintenance cost.

Movable flat electrode

Fixed flat electrode

Projection

Weld during formation

AC Power supply


Force

Force



2.3. Seam welding

2.3.1. Principle of seam welding

The seam welding is a modified technological form of spot welding that permits to obtain a

continuous weld line (weld seam). The electrodes are rotating wheels. The two sheet metals to

be welded are placed between the two wheel electrodes. While theses wheel electrodes

moves, the passage of a high electric current combined with a mechanical pressure creates a

melting line (melting seam). Figure 2.10 [2.10] (Partially modified compared to the original

reference for educational purpose) depicts the principle of the seam welding.

Figure 2.10. Principle of seam welding.

2.3.2. Advantages/Limitations of seam welding

The seam welding presents some principal advantages:

• Continuous welding (seam weld)/Suitable for gas and liquid tights.

• Several seam welds can be carried out in parallel/More productivity.

The seam welding presents, also, some principal limitations:

Seam weld

AC Power supply




• Higher electrode cost.

• Welding thickness up to 3 mm no more.

2.4. Butt welding

2.4.1. Principle of butt welding

The butt welding can be considered, in one way or another, as a modified technological

form of spot welding that permits to obtain an end-to-end (butt) welding, mainly between

pipes, rods and wires. The electrodes are two clamps (one movable and the other fixed). The

two workpieces are placed end-to-end, each one connected to one clamp. The passage of a

high electric current combined with a mechanical pressure creates an end-to-end melting (butt

weld). Figure 2.11 [2.11] (Partially modified compared to the original reference for

educational purpose) depicts the principle of the butt welding.

Figure 2.11. Principle of butt welding.

2.4.2. Advantages/Limitations of butt welding

The butt welding presents some principal advantages:

• Dissimilar metal can be welded.

• Fast welding.

• 100% strength factor.




• Low cost process.

The butt welding presents, also, some principal limitations:

• Metal loss during welding.

• Fire hazards.

3. Laser-hybrid welding

3.1. Principle of Laser-hybrid welding

The Laser-hybrid welding is an advanced welding technology that combines the principles

of Laser welding and arc welding (GMAW, GTAW and PAW), creating, so, an incorporated

welding process. Depending on the used arc welding process, three principal types of Laser-

hybrid welding are distinguished:

• GMAW-augmented Laser. (The first hybrid welding introduced in industrial

applications).

• GTAW-augmented Laser (The first hybrid welding to be researched and developed).

• PAW-augmented Laser.

In the Laser-hybrid welding, a laser beam and an electrical arc, influencing and supporting

each other, act simultaneously in the same welding zone. The Laser beam, with an energy-

flow density in the order of 1 MW/cm2, applied on a spot of the material to be welded, heats

up this spot until vaporization. A cavity, called keyhole, is then created. Figure 2.12 [2.12]

depicts the principle of the Laser-hybrid welding. Figure 2.13 [2.13] depicts a Laser-hybrid

welding prototype.

3.1.1. Advantages/Limitations of Laser-hybrid welding

The Laser-hybrid welding presents some principal advantages:

• Enhanced weld speed and filler metal deposition rate.

• Reduced distortion (thanks to the low heat input).

• Improved weld mechanical properties (thanks to the low heat input).

• Welding from only one side is accommodated.



• Enhanced penetration.

The Laser-hybrid welding presents one main limitation:

• Process parameters determination takes a lot of time and resources in order to

obtain good weld results.

Figure 2.12. Principle of Laser-hybrid welding.

Figure 2.13. Laser-hybrid welding prototype.



4. References

[2.1] Admin, Plasma Arc Welding: Principle, Working, Equipment’s, Types, Application, Advantages and Disadvantages, https://www.mech4study.com/2017/04/plasma-arc-welding-principle-working-equipment-types-application-advantages-and-disadvantages.html, Access date: 11/07/2020 11:00 GMT

[2.2] Jeff Grill, The Plasma Welding Process, https://weldguru.com/plasma-welding-process/, Access date: 11/07/2020 11:18 GMT

[2.3] PLASMA ARC WELDING (PAW), https://www.mechanicatech.com/Joining/paw.html, Access date: 11/07/2020 11:28 GMT

[2.4] tvm@2017, Plasma Arc Welding Process- Principle, Main Parts, Working, Advantages and Disadvantages with Application, https://www.theweldingmaster.com/plasma-arc-welding/, Access date: 11/07/2020 14:09 GMT

[2.5]https://learnengineering.wordpress.com/2016/02/06/electron-beam-machining-ebm/, Access date: 11/07/2020 15:43 GMT

[2.6] tvm@2017, Laser Beam Welding – Equipment, Principle, Working with Advantages and Disadvantages, https://www.theweldingmaster.com/laser-beam-welding/, Access date: 11/07/2020 17:40 GMT

[2.7] T.S. Hong, Morteza Ghobakhloo, Weria Khaksar, Robotic Welding Technology, Comprehensive Materials Processing, 6 (2014) 77-99, https://doi.org/10.1016/B978-0-08-096532-1.00604-X

[2.8] Evolution and Applications Of Spot Welding!, https://www.wcwelding.com/spot-welding.html, Access date: 11/07/2020 19:29 GMT

[2.9] Admin, Resistance Welding: Principle, Types, Application, Advantages and Disadvantages, https://www.mech4study.com/2017/04/resistance-welding-principle-types-application-advantages-and-disadvantages.html, Access date: 11/07/2020 23:00 GMT

[2.10] Dhiya Alden Jabr Alawi, MODAL ANALYSIS OF RESISTANCE SPOT WELDING FOR DISSIMILAR PLATE STRUCTURE (2017), Thesis

[2.11] Dmitri Kopeliovich, Resistance Welding (RW), https://www.substech.com/dokuwiki/doku.php?id=resistance_welding_rw, Access date: 11/07/2020 23:47 GMT

[2.12] Lincoln Electric Company, NX-1.50 03/11, https://www.lincolnelectric.com/assets/US/EN/literature/nx150.pdf, Access date: 11/08/2020 10:05 GMT

[2.13] Cloos Company, Laser Hybrid Weld -Laser Hybrid MIG/MAG head: Standard -Standard head, https://www.cloos.de/de-en/products/qineo/laser-hybrid-weld/laser-hybrid-mig-mag-head-standard/standard-kopf/, Access date: 11/08/2020 10:30 GMT

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Solid state welding processes


Chapter 3. Solid state welding processes.

The Solid Stated Welding (SSW) refers to non-conventional welding processes. Unlike the

Liquid State Welding (LSW) processes, the SSW process doesn’t use any external heat for

welding. Four principal technological varieties of SSW processes can be distinguished:

• Friction Welding process (FRW)

• Ultrasonic Welding process (USW)

• Diffusion Welding (DW)

• Explosion welding (EXW)

1. Friction Welding (FRW) process

1.1. Principle of the Friction Welding (FRW) process

The Friction Welding (FRW) is a non-conventional welding process. It belongs to the

Solid State Welding (SSW) processes. The FRW consists in using a relative motion (rotary or

linear movement) between 2 workpieces associated with a lateral force (called upset). The

combination between the relative motion and the upset will ensure a plastic displacement and

a fuse between the 2 workpiece friction surfaces. Both metals and thermoplastics can be easily

welded using FRW. Figure 3.1 depicts the principle of the Rotary FRW (RFW) [3.1]. Figure

3.2 depicts the principle of the Linear FRW (LFW) [3.2]. Figure 3.3 presents an RFW

machine [3.3]. Figure 3.4 presents an LFW machine [3.4].

1.2. Advantages/Limitations of the Friction Welding (FRW) process

The Friction Welding process presents some principal advantages:

• Both similar and dissimilar materials can be welded.

• No filler materials, no shielding gases, no fluxes are required.

• No porosity or slag inclusions (solid state process).

• High weld strength (full surface weld).

• Fast welding process.




The Friction Welding presents some principal limitations:

• Limited joint designs.

• Difficulties to weld materials that cannot be forged.

• High cost equipment.

Figure 3.1. Principle of the Rotary Friction Welding (RFW).

Figure 3.2. Principle of the Linear Friction Welding (LFW).



Figure 3.3. Rotary Friction Welding (RFW) machine.

Figure 3.4. Linear Friction Welding (LFW) machine.



2. Ultrasonic Welding (USW) process

2.1. Principle of the Ultrasonic Welding (USW) process

The Ultrasonic Welding (USW) is a non-conventional welding process. It belongs to the

Solid State Welding (SSW) processes. The USW consists in using ultrasonic vibrations

(based on ultrasonic waves with a frequency in the order of 20 kHz to 30 kHz) that creates a

dynamic shear stress between the surface contacts of 2 workpieces to be welded. The dynamic

shear stress will generate a local plastic deformation while the friction will generate a heat

between the 2 contact surfaces. These plastic deformation and heat will create a weld joint at

the surface interface between the 2 workpieces. Both metals and plastics can be easily welded

using the USW. Figure 3.5 depicts the principle of USW [3.5]. Figure 3.6 depicts the USW

machine [3.6].

Figure 3.5. Principle of the Ultrasonic Welding (USW).

Figure 3.6. Ultrasonic Welding (USW) machine.



2.2. Advantages/Limitations of the Ultrasonic Welding (USW) process

The Ultrasonic Welding (USW) process presents some principal advantages:



• High weld strength (full surface weld) without external heat.

• Good weld surface finishing.

• Fast welding process.


The Ultrasonic Welding (USW) process presents some principal limitations:

• Not adapted to weld thick materials (no more than 2.5 mm for aluminum for

example).

• High cost equipment for the tooling fixture.

• Generated vibrations can damage electronic components.

3. Diffusion Welding (DW)

3.1. Principle of the Diffusion Welding (DW) process

The Diffusion Welding (DW) is a non-conventional welding process. It belongs to the

Solid State Welding (SSW) processes. The DW consists in creating microscopic bondings

(joints) between the atoms of the 2 workpiece metallic surfaces to be welded. These atomic

bondings are created under a high temperature (50-75% of the material melting temperature)

and a high pressure. It is to note that a solid filler metal may be inserted between the 2

workpiece surfaces to be welded. The DW is particularly used to weld alternating layers of

thin sheet metals (“sandwich materials”). The DW is widely used to weld high-strength and

refractory metals. Figure 3.7 depicts the principle of the DW [3.7]. Figure 3.8 depicts the DW

machine [3.8].



Figure 3.7. Principle of the Diffusion Welding (DW).

Figure 3.8. Diffusion Welding (DW) machine.

3.2. Advantages/Limitations of the Diffusion Welding (DW) process

The Diffusion Welding (DW) process presents some principal advantages:


• Mechanical properties of the welded surfaces similar to those of the base metals.

• Less shrinkage and stress.

• Possible multiple weld in the same time.


Holding

High Pressure

Holding

Heat up



The Diffusion Welding (DW) process presents some principal limitations:

• High cost (equipment and preparation of the surfaces to be welded).

• Long time welding.

• Required vacuum or protective atmosphere.

• Particular attention when welding workpieces with different thermal expansions.

4. Explosion Welding (EXW)

4.1. Principle of the Explosion Welding (EXW) process

The Explosion Welding (EXW) is a non-conventional welding process. It belongs to the

Solid State Welding (SSW) processes. The EXW consists in accelerating (at extremely high

velocity) a thin corrosion resistant (stainless steel, Nickel, titanium, zirconium) workpiece

(cladding) into a thick carbon steel workpiece (backer), using a controlled detonation of

chemical explosives. It is to note that all oxides and impurities between cladding and backer

are expelled during the EXW process. Figure 3.9 depicts the principle of the EXW [3.9].

Figure 3.10 depicts an aluminum (cladding)-steel (backer) metallic composite [3.10].

Figure 3.9. Principle of the Explosion Welding (EXW).

Backer

Cladding

Detonation

Explosive powder



Figure 3.10. Principle of the Explosion Welding (EXW).

4.2. Advantages/Limitations of the Explosion Welding (EXW) process

The Explosion Welding (EXW) process presents some principal advantages:



• Mechanical properties of the welded materials not affected.

• Large surface can be weld in one pass.

• High joining rate.

The Explosion Welding (EXW) process presents some principal limitations:

• Only ductile metals with high toughness can be welded.

• Dangerous phenomenon (explosion)/ Particular precautions are required.

• Noisy pollution (detonation).

• Limited joint designs.

5. References

[3.1] tvm@2017, What is Friction Welding Process and How it Works?, https://www.theweldingmaster.com/friction-welding/, Access date: 11/13/2020 13:14 GMT

Aluminium (Cladding)

Steel (Backer)



[3.2] TWI Ltd, LINEAR FRICTION WELDING, https://www.twi-global.com/technical-knowledge/job-knowledge/linear-friction-welding-146, Access date: 11/13/2020 13:45 GMT

[3.3] Admin, Friction Welding : Principle, Working, Types, Application, Advantages and Disadvantages, https://www.mech4study.com/2017/04/friction-welding-principle-working-types-application-advantages-and-disadvantages.html, Access date: 11/13/2020 15:55 GMT

[3.4] U. U. Ofem, P. A. Colegrove, A. Addison, M. J. Russell, Energy and force analysis of linear friction welds in a medium carbon steel, Science and Technology of Welding & Joining 16 (6) (2010) 479-485, https://doi.org/10.1179/136217110X12731414739790

[3.5] Dongkyun Lee, Elijah Kannatey-Asibu, Wayne Cai, Ultrasonic Welding Simulations for Multiple Layers of Lithium-Ion Battery Tabs, Journal of Manufacturing Science and

Engineering 135 (6) (2013) 061011, https://doi.org/10.1115/1.4025668

[3.6] Craig Freudenrich, How Ultrasonic Welding Works, https://science.howstuffworks.com/ultrasonic-welding.htm

[3.7] Metal Technology Co. Ltd., The diffusion bonding process, https://www.kinzoku.co.jp/en/technical_info/article_20170911_02.html, Access date: 11/14/2020 06:41 GMT (Partially modified for educational purpose)

[3.8] Joel Hemanth, Scanning Electron Microscopy (SEM) Analysis and Hardness of Diffusion Bonded Titanium-Titanium and Titanium-Copper Plates with Static Force and without Interlayers, Open Journal of Composite Materials 7 (2) (2017) 105-116, https://doi.org/10.4236/ojcm.2017.72007

[3.9] NobelClad, The Process of Explosion Welding, https://www.youtube.com/watch?v=XMSaX-3tOUw, Access date: 11/14/2020 12:14 GMT (Partially modified for educational purpose)

[3.10] MEISITU, Explosion welding aluminum to steel, https://bimetallic-sheet-plate.com/news/explosion-welding-aluminum-to-steel-clad-plate.html, Access date: 11/14/2020 12:22 GMT (Partially modified for educational purpose)

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Welding symbols


Chapter 4. Welding symbols.

This chapter details some aspects of welding symbols based on the American Welding

Society (AWS) document: ANSI/AWS A2.4 Standard Symbols for Welding, Brazing, and

Nondestructive Examination. The welding symbol in a drafting permits to identify the

intended welding and helps, so, to correctly carry out weld beads in welded structures.

1. Welds types

In order to better understand the welding symbols, it is imperative to know the main weld

types.

1.1. Fillet weld

A fillet weld is a joint between 2 workpieces at an approximate right angle. Figure 4.1

depicts the principal types of fillet weld (single and double) [4.1].

Figure 4.1. Fillet welds.

1.2. Groove weld

A groove weld is a bead deposited in a groove joint between 2 workpieces. Figure 4.2

depicts the principal types of groove weld [4.1].



Figure 4.2. Groove welds.

1.3. Surfacing weld

A surfacing weld (known also as hardfacing or wearfacing) is not a joint. It is rather

considered as one or more beads deposited on worn surfaces or edges in order to create new

hard and wear-resistant metal layer. New surface properties and dimensions are, then,

obtained. Figure 4.3 depicts surfacing welds [4.1].

Figure 4.3. Surfacing welds.

1.4. Plug weld

A plug weld is a circular weld carried out through a workpiece of a lap or tee joint joining

that workpiece to the other. It is to note that the plug weld can be made through a hole



(partially or completely filled with weld metal) in the first workpiece. Figure 4.4 depicts plug

welds [4.1].

Figure 4.4. Plug welds.

1.5. Slot weld

A slot weld is carried out in an elongated hole (partially or completely filled with weld

metal) through a workpiece of a lap or tee joint joining that workpiece to the other. Figure 4.5

depicts slot welds [4.1].

Figure 4.5. Slot welds.

1.6. Flash weld

A flash weld is a type of resistance weld (chapter 2 §2) made over the whole abutting

surface of 2 workpieces. The pressure application is carried out after the heating period.

Figure 4.6 depicts a flash weld [4.1].

Figure 4.6. Flash weld.



1.7. Seam weld

A Seam weld is a continuous fuse line, in the forms of arc seam or resistance seam

(chapter 2 §2) that joins 2 workpieces. Figure 4.7 depicts seam welds [4.1].

Figure 4.7. Seam welds.

1.8. Spot weld

A Spot weld is a fuse dot, in the forms of arc dot or resistance dot (chapter 2 §2) that joins

2 workpieces. Figure 4.8 depicts spot welds [4.1].

Figure 4.8. Spot welds.

1.9. Upset weld

An upset weld is a type of resistance weld (chapter 2 §2) made progressively over the

whole abutting surface of 2 workpieces. The pressure application is carried out before and

during the heating period. Figure 4.9 depicts an upset weld [4.1].

Figure 4.9. Upset weld.



2. Welding symbols chart

The American Welding Society (AWS) provides a comprehensive welding symbols chart

[4.2] (Figure 4.10) that summarizes the welding symbols standardization.

Figure 4.10. Welding symbols chart.



3. Basic welding symbol examples

Fillet and groove welds are the most common types of weld in industrial application. This

section presents some relevant basic examples about welding symbols of fillet and groove

welds. These examples will permit to better assimilate the AWS basic welding symbol.

3.1. Welding symbol for fillet welds

3.1.1. Location

Figure 4.11 summarizes the most common welding symbol for fillet weld location [4.3].

Figure 4.11. Location significance of arrow.

3.1.2. Size

Figure 4.12-13 depicts some welding symbols for fillet weld size [4.3].

Figure 4.12. Welding symbols for fillet weld size (weld cross section).



Figure 4.13. Welding symbols for fillet weld size (weld cross section and length).

3.1.3. Pitch

Figure 4.14 depicts some welding symbols for fillet weld pitch [4.3].

Figure 4.14. Welding symbols for fillet weld pitch.

3.1.4. All around

Figure 4.15 depicts some welding symbols for all around fillet weld [4.3].



Figure 4.15. Welding symbols for all around fillet weld.

3.2. Groove welds

3.2.1. Types

Figure 4.16 depicts some welding symbols for groove weld types [4.4].

Figure 4.16. Welding symbols for groove weld types.



3.2.2. Size

Figure 4.17 depicts some welding symbols for groove weld size [4.4].

Figure 4.17. Welding symbols for groove weld size.

4. Specific welding symbol examples

Sometimes, it is helpful to add some specific informations about the welds in the welding

symbols. This section presents some relevant examples about welding symbols that gives

specific information about fillet and groove welds. These examples will permit to better

assimilate the AWS specific welding symbol.

4.1. Back and backing welds

Figure 4.18 depicts some specific welding symbols about back and backing weld carried

out in groove welds [4.4].

13

19

9.5

28.5



Figure 4.18. Specific welding symbols for groove back and backing welds.

4.2. Weld contours and finishing of welds

Figure 4.19 depicts some specific welding symbols about weld contours and finishing

welds [4.4].

Figure 4.19. Specific welding symbols for weld contours and finishing welds.

Figure 4.20 depicts some specific welding symbols about flush and convex contour weld

carried out in groove welds [4.4].



Figure 4.20. Specific welding symbols for flush and convex contour welds.

5. References

[4.1] Jeff Grill, Weld Types & Joints, https://weldguru.com/weld-types-joints/#:~:text=%20There%20are%20several%20types%20of%20fillet%20weld%3A,intermittent%20fillet%20welds%20in%20a%20lap...%20More%20 (2019), Access date: 11/26/2020 17:05 GMT

[4.2] American Welding Society, Errata for AWS A2.4-98, Standard Symbols for Welding, Brazing, and Nondestructive Examination. Correction to the Welding Symbol Chart for AWS A2.4-98, pages 106 and 107.

[4.3] Garry Pace, Intro to Welding Symbols Fillet Welds, https://www.youtube.com/watch?v=6L-ku_Bz1r8, Acces date: 11/27/2020 11:39 GMT (Partially modified for educational purposes)

[4.4]Garry Pace, Introduction to Weld Symbols Groove Welds, https://www.youtube.com/watch?v=PpFoi75xJME, Acces date: 11/28/2020 04:03 GMT (Partially modified for educational purposes)

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Resistance/Sizing of weld beads


Chapter 5. Resistance/Sizing of weld beads

The size of a weld bead directly influences its mechanical resistance under the effect of

imposed loads. Thus, it is imperative to correctly size a weld bead on the basis of a calculation

standard (Eurocode 3 Standards). Based on a special knowledge about the weld constituent

elements and the principal types of loads imposed on a weld, this chapter explains how to size

the weld bead knowing the maximum imposed load, and how to evaluate the resistance of a

weld bead knowing its size.

1. Weld constituent elements

1.1. Effective throat thickness

The effective throat thickness a is the distance between the root and the external surface of

the weld bead excluding allowances as it is depicted by Figure 5.1 [5.1].

Figure 5.1. Effective throat thickness [5.1].

It is to note that for a fillet weld, the effective throat thickness should be mm 3≥a [5.2].

1.2. Useful length

The useful length is the actual length from which the crater extremities are subtracted

(starting and fading of the arc). The crater extremity is considered equal to the effective throat

thickness:

aLLL actualuseful ×−== 2

Very short weld beads ( aLL ×<< 6or mm 30 ) cannot be considered in terms of

resistance [5.2].



1.3. Effective area

The effective area of the weld is depicted by Figure 5.2 [5.1].

Figure 5.2. Effective area for straight and curved welds [5.1].

The effective area A is obtained based on the length L and the effective throat thickness a

of the weld as follows:

bead theof thickness-midat measured Radius :with

weldcurved afor : 2

eldstraight w afor :

m

m

R

aRA

aLA

××=×=

π

2. Principal types of loads



Three principal types of loads can be imposed on a weld:

2.1. Weld subjected to tensile

When the load is perpendicular to the weld, we talk about the tensile as it is depicted by

Figure 5.3 [5.1].

Figure 5.3. Weld subjected to tensile [5.1].

2.2. Weld subjected to pure shear

When the load is parallel to the weld, we talk about pure shear as it is depicted by

Figure 5.4 [5.1].

Figure 5.4. Weld subjected to pure shear [5.1].

2.3. Weld subjected to tensile and shear

When the load is both perpendicular and parallel to the weld, we talk about tensile and

shear as it is depicted by Figure 5.5 [5.1].

Figure 5.5. Weld subjected to tensile and shear [5.1].



3. Stresses within welds

Three types of stress are distinguished within a weld as it is depicted by Figure 5.6 [5.1]:

• ⊥σ : Normal stress perpendicular to the throat plane of the weld.

• ⊥τ : Shear stress in the throat plane of the weld and perpendicular to the weld axis.

• //τ : Shear stress in the throat plane of the weld and parallel to the weld axis.

Figure 5.6. Normal and shear stresses within a weld [5.1].

The equivalent Von-Mises stress in the weld is written as:

( )2//

22 3 ττσ +×+= ⊥⊥wσ

The Eurocode 3 Standards postulates that the design resistance of a fillet weld can be

obtained using either the so called “Directional method” or the “Simplified method” [5.2].

Directional method



The design resistance of a fillet weld using the directional method is written as:

( )22

222 90with 3

M

u

Mw

u//

γ

f.

γβ

fττσ ≤≤+×+ ⊥⊥⊥ σ

Where:

[ ]

[ ] bearing)in plates and pins rivets, bolts, welds,of resistance (for the 1.25factorsafety Partial :

5.3 2-10025 EN from 7 Table fromen tak

joinedpart weaker theofstrength Tensile ultimate Nominal :

5.2 Standards 8-1-1993 EN from 4.1 Table fromen factor takn correlatio eAppropriat :

2 =M

u

w

γ

f

β



Simplified method

The design resistance of a fillet weld using the simplified method is written as:

2

dvw,dvw,Rdw,Rdw,Edw,

3/ with with

Mw

u

γβ

ffafFFF ==≤

Where:

ickness throat thEffective :

weld theofstrength shear Design :

lengthunit per resistance dDesign wel :

lengthunit per force weld theof ueDesign val :

dvw,

Rdw,

Edw,

a

f

F

F

4. Practical exercises

4.1. Directional method for design resistance of fillet weld/Weld sizing

4.1.1. Weld subjected to pure shear

Fillet welds are subjected to pure shear stress as it is depicted by Figure 5.7 [5.1]:



Figure 5.7. Fillet welds subjected to pure shear stress [5.1].

It is clear, in this case, that there is no normal stress and that shear stress is parallel to the

weld. There is no perpendicular shear stress.

The design resistance of a fillet weld using the directional method permits to verify the

weld resistance as follows:

( )2

//

2

222 3030Mw

u

Mw

u//

γβ

f

γβ

fτ ≤≤+×+ τ

{

25.1 weldsof Resistance

85.0S275

Mpa 500 examplefor take weMPa;560 toMPa410mm 10t

S275JR

Mpa 10050102

100000

2

2

//

welds2

//

=

=

===

=××

=××

==

M

w

uu

γ

β

ff

La

F τττ

( ) verifiedresistance Weld:MPa 159.470MPa 21.17332

222 ≤≤+×+ ⊥⊥Mw

u//

γβ

fττσ



Also, it is possible to determine the minimum size of weld (minimum area of the weld:

minimum length for a fixed throat or minimum throat for fixed length) that permits to resist to

the imposed load as follows:

( ){ 2

welds22

//

stressshear Pure

2

222

2333

Mw

u

Mw

u

Mw

u//

γβ

f

La

F

γβ

f

γβ

fττσ ≤

××≤≤+×+ ⊥⊥ τ

For a fixed throat a=10 mm, the minimum length of the weld is written as:

4342144 344 21 min

min

mm 40.18500102

25.185.01000003

23 2

L

L

u

Mw LLfa

γβFL ≥

××××≥

××××

≥

It is to note here that aL ×≤ 6min (very short weld cannot be considered in terms of

resistance). So, this minimum length that can be used is mm 606 =×= aL .

4.1.2. Weld subjected to tensile and shear

Fillet welds are subjected to tensile and shear stresses as it is depicted by Figure 5.8 [5.1]:

Figure 5.8. Fillet welds subjected to combined tensile and shear stresses [5.1].

In this case, that there is a normal stress and perpendicular shear stress applied on the

welds.



The design resistance of a fillet weld using the directional method permits to verify the

weld resistance as follows:

( )22

222 90with 03

M

u

Mw

u

γ

f.

γβ

fτσ ≤≤+×+ ⊥⊥⊥ σ

{

{


8.0S235


S235JR

MPa 13.8985722

150000

22

22

2

welds2

welds2

=

=

===

=×××

==

××===

×××==

⊥⊥

⊥

⊥

M

w

uu

γ

β

ff

La

F

La

F

τσσττ

σσ

( ) verifiedresistance Weld:MPa 4.302MPa 13.89 with MPa 204MPa 26.178

90with 03

22

222

≤≤

≤≤+×+ ⊥⊥⊥M

u

Mw

u

γ

f.

γβ

fτσ σ

Also, it is possible to determine the minimum size of weld (minimum area of the weld:

minimum length for a fixed throat or minimum throat for fixed length) that permits to resist to

the imposed load as follows:

( )

( )

2

22

222stressshear and tensileCombined

22

222

2

90with 03

90with 3

Mw

u

M

u

Mw

u

M

u

Mw

u//

γβ

f

La

F

γ

f.

γβ

fτσ

γ

f.

γβ

fττσ

≤××

≤≤+×+

≤≤+×+

⊥⊥⊥

⊥⊥⊥

σ

σ

For a fixed throat a=7 mm, the minimum length of the weld is written as:

434214434421 min

min

mm 36.0842072

25.18.0150000

22

L

L

u

Mw LLfa

γβFL ≥

××××≥

××××≥

It is to note here that aL ×≤ 6min (very short weld cannot be considered in terms of

resistance). So, this minimum length that can be used is mm 426 =×= aL .



For a fixed length L=45 mm, the minimum throat of the weld is written as:

43421

4434421 min

min

mm 5.61420452

25.18.0150000

2

2

a

a

u

Mw aafL

γβFa ≥

××××≥

××××≥

4.2. Simplified method for design resistance of fillet weld

The shear resistance of a welded end plate is depicted by Figure 5.9 [5.4]:

Figure 5.9. Shear resistance of welded end plate [5.4].

{ Rdw,

kN 500

Edw,Rdw,Edw, VVFF ≤≤

{ {ah

aγβ

fp

Mw

u

LFV×−

×

××=2

3/

Rdw,Rdw,

2

2


85.0S275


S275JR

mm 184mm 8a

mm 200

2 =

=

===

=

=

=

M

w

uu

p

γ

β

ff

Lh



kN 88.719N/mm 2.1956

mm 8

25.1

85.0

MPa 450

mm 184

Rdw,

Rdw,

2

==

==

==

=

VF

a

γ

β

f

L

M

w

u

verifiedresistance Weld:kN 88.719kN 500 Rdw,Edw, =≤= VV

5. References

[5.1] Fabien Segovia, Dimensionnement de soudures avec l'eurocode 3, https://www.youtube.com/watch?v=PPJD3hXPhL8&t=126s, Access date: 01/03/2021 22:39 GMT

[5.2] European Standard, Eurocode 3: Design of steel structures - Part 1-8: Design of joints, EN 1993-1-8:2005 (E)

[5.3] British Standard, Hot rolled products of structural steels —Part 2: Technical delivery conditions for non-alloy structural steels, BS EN 10025-2:2004

[5.4] Dilakshana Mayadunne, Steel Connections | Welded Joint Design | Pinned Joints | Rigid Joints (Fixed) | Eurocode 3 | EN1993, https://www.youtube.com/watch?v=pEzuLkMzHzM, Access date: 01/03/2021 22:49 GMT

Higher Institute of Technological Studies_Gafsa-Tunisia Permanent joints Department of Mechanical Engineering Other types of permanent joints


Chapter 6. Other types of permanent joints

Welding is considered as the most common type of permanent joint in the field of metallic

construction. However, there are very useful other types of permanent joints used in metallic

constructions, mainly the brazing, the riveting and the crimping. This chapter presents each

one of these permanent joints and their industrial applications. The choice of the appropriate

joint is carried out based on the specifications involved by the appropriate industrial

applications.

1. Brazing process

1.1. Principle of the brazing process

The brazing is a joining process that permits to create a permanent joint between similar or

dissimilar metals using a filler metal that present lower melting point than the adjoining metal.

The melting point of the filler metal is above 450°C. A protective flux, such as Borax, is

applied on metal parts in order to prevent oxidation. Four principal types of brazing are

distinguished:

• Torch brazing: Figure 6.1 [6.1] depicts the principle of torch brazing. The torch

brazing process uses a hot gas jet from a torch towards a joint in order to heat the

workpieces and melt the filler metal. Thus, a joint is created between the workpieces.

Since the melting point of the filler metal is considerably lower than the oxidation

temperature of the workpieces, the joint is protected against oxidation.

Figure 6.1. Torch brazing principle [6.1].



• Furnace brazing: Figure 6.2 [6.1] depicts the principle of furnace brazing. The

furnace brazing process heats a whole assembly (multi-joints) to a temperature where

the filler alloy melts and flow into the joint. After cooling, a permanent joint is

obtained. It is to note that the furnace brazing permits to obtain up to thousands of

joints simultaneously.

Figure 6.2. Furnace brazing principle [6.1].

• Electric Resistance brazing: Figure 6.3 [6.2] depicts the principle of electric

resistance brazing. The resistance brazing process is similar to the spot welding

(Chapter 2 §2.1) except that only the filler metal is melt and not the workpieces. Thus,

a joint is created between the workpieces.

Figure 6.3. Electric resistance brazing principle [6.2]. I



• Dip brazing: Figure 6.4 [6.1] depicts the principle of dip brazing. The dip brazing

process permits to obtain simultaneous multiple joints with different workpiece

thicknesses. It consists, firstly, to fix the workpieces to be joined and to apply the

brazing compound (filler metal+flux) on the joint interfaces (contact surfaces between

the workpieces) in slurry form. The assembly is then pre-heated up to a temperature

right below the melting point of the filler metal. This will permit to reduce the stay

time of the workpieces to be joined in the bath of molten salt. It is to note that the

application of flux permits to keep the filler metal in place while being dipped

(submerged) in the molten salt bath which acts as a heat transfer medium. Finally, the

assembly is completely dipped into the molten salt bath. As the melting of the filler

metal begins, the flux dissolves in the bath and the filler metal occupies the joint

space. Thus, permanent joints between the workpieces are created.

Figure 6.4. Dip brazing principle [6.1].

1.2. Industrial applications of the brazing process

The brazing process is appropriate for the industrial applications that involve permanent

joints presenting the main following specifications [6.3]:

• Joint between workpieces with small overall size (smaller than the usual overall size

of the welded workpieces).

Before brazing

After brazing



• Joint between workpieces with similar and dissimilar metals.

• Large mass production.

2. Riveting process

2.1. Principle of the riveting process

The riveting is a joining process that permits to create a permanent joint between similar or

dissimilar metals using a rivet, a backing up bar and a die as it is depicted by Figure 6.5 [6.4].

It is to note that the riveting can be carried out hot or cold, manually or mechanically. The

holes through which rivets are applied can be made by punching or drilling.

Figure 6.5. Riveting principle [6.4].



The riveting process can create both lap joint and butt joint (single, double, chain and Zig-

Zag riveted joint) as it is depicted by Figure 6.6 [6.5].

Figure 6.6. Types of riveted joints [6.5].

It is to note that there are some rules that must be respected when carrying out a riveting

operation (Figure 6.7 [6.6]).

Figure 6.7. Principal riveting rules [6.6].

d3P

Pitch :P

t0.625tt

strap double of sThicknesse: t,t

t125.1t

strap single of Thickness:t

t6d

plates joined theof Thickness :t

rivet ofdiameter :d

21

21

1

1

×=

×==

×=

×=



2.2. Industrial applications of the riveting process

The riveting process is appropriate for the industrial applications that involve permanent


• Joints between workpieces for which the thermal effects must be avoided.

• Joints between workpieces having poor weldability.

• Joints between workpieces with heterogeneous materials (asbestos friction lining-steel

for example).

• Joints between workpieces subjected to intense vibrations.

• Joints between workpieces in aluminum aircraft structures.

3. Mechanical crimping process

3.1. Principle of the crimping process

The mechanical crimping is a joining process that permits to create a permanent joint

between metal (or other ductile material) workpieces by bending (deforming) one or both of

them to hold the other. The crimping allows avoiding the Heat-Affected Zone (HAZ)

encountered with welding joints. Figure 6.8 [6.8] depicts the principle of crimping process.

Figure 6.8. Crimping principle [6.8].

3.2. Industrial applications of the crimping process

The crimping process is appropriate for the industrial applications that involve permanent




• Joints between sheet metal workpieces (Cladding, boilermaking, etc.).

• Joints between metal pipes (ductwork in ventilation and air conditioning systems,

rainwater pipe, etc.).

The crimping process is also used in:

• Reducing pipe diameter in order to ensure a male (uncrimped pipe)-female

(crimped pipe) joint. The diameter reduction is carried out by transforming the

circular profile at the end of the pipe into a wavy profile. It is to note that this

specific “crimping” joint is neither permanent nor waterproof.

4. References

[6.1] Makers Legacy, Brazing Methods, https://makerslegacy.com/brazing/what-is-brazing/, Access date: 01/10/2021 14:41 GMT

[6.2] Hartmut Schmoor , Brazing processes, http://www.schmoor-brazing.com/en/brazing-processes.html, Access date: 01/10/2021 14:47 GMT, Partially modified for educational purposes

[6.3] William Harris, Brazing Applications and Advantages, https://science.howstuffworks.com/brazing5.htm, Access date: 01/21/2021 08:49 GMT.

[6.4] KTU Web, Introduction to Riveted Joints - A Quick Review of Different Types of Rivet Joints, https://www.youtube.com/watch?v=YQoegtLFL5A, Access date: 01/20/2021 20:55 GMT

[6.5] Mecholic, Types of Riveted Joints – Lap Joint, Butt Joint, Single Strap, Double Strap, Chain and Zig-Zag Riveting, https://www.mecholic.com/2018/10/types-of-riveted-joints.html, Access date: 01/20/2021 21:04 GMT

[6.6] ITI LIFE GYAN, BUTT JOINT - Single Riveted (Single Strap) By Surender Sharma (Rivets Video-8), https://www.youtube.com/watch?v=Hwx48ZEjhO4, Access date: 01/21/2021 09:11 GMT

[6.7] Club Technical, Rivet and Riveted Joints, Applications, Advantages, Disadvantages, https://clubtechnical.com/rivet, Access date: 01/21/2021 11:27 GMT

[6.8] Christian Weddeling, Electromagnetic Form-Fit Joining, Thesis for: Dr.-Ing. in Mechanical EngineeringAdvisor: A. Erman Tekkaya, Glenn S. Daehn, December 2014, https://www.researchgate.net/publication/272823106_Electromagnetic_Form-Fit_Joining, Access date: 01/21/2021 12:19 GMT

[6.9] Designing Buildings Wiki, Crimp, https://www.designingbuildings.co.uk/wiki/Crimp, Access date: 01/21/2021 11:59 GMT

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