Messages from Conference Chairman - สถาบันเหล็กและ ...

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Messages from Conference Chairman

Metal-working industries have always held their importance in engineering works. This trend will unarguably continue through the future. The field of Metallurgy will, therefore, continually need lots of input especially in the form of research works from both academic and industrial sectors around the world. In industrialized countries, such as United States, European countries, South Korea, and Japan, Conferences in Metallurgy field have continually been held many times each year. The 1st Thailand Metallurgy Conference was successfully held the first time in Thailand in 2007. It was initiated by Director of the Iron and Steel Institute of Thailand (ISIT) and Director of the National Metals and Materials Technology Center of Thailand (MTEC) together with research Institutions in Thailand. The meeting was really successful and received much attention from people in all sectors related to the field. The last success has strong driving force for the next conference to be organized. Given an opportunity to organize The 2nd Thailand Metallurgy Conference (2 TMETC), “Metallurgy for Sustainable Development”, in 2008, King Mongkut’s University of Technology (KMUTT) is hosting this conference together with ISIT and MTEC. This conference will be part of the 48th Anniversary of KMUTT, found in 1960. In 2008 Conference, all paper contributions will be categorized into oral and poster presentations. And again, those who will receive the awards of “The Young Outstanding Metallurgist” and “Thailand Metallurgist of the Year” will be announced during the conference. The best Oral and Poster presentations will also rewarded. We do hope that a fruitful discussion will be produced and new scientific contacts and friendships will be established. On behalf of the organizing committee, I would like to thank all participants with the warmth welcome. Wish all of you have a pleasant stay during the 2nd Thailand Metallurgy Conference.

(Assoc. Professor Dr. Booncharoen Sirinaovakul)

Conference Chairman

The 2nd Thailand Metallurgy Conference (2 TMETC)

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Organized by King Mongkut’s University of Technology Thonburi Iron and Steel Institute of Thailand National Metal and Materials Technology Center

Co-organized by Chulalongkorn University Chiang Mai University Kasetsart University Mahidol University Narasuan University Prince of Songkla University Suranaree University of technology Thammasart University King Mongkut’s University of Technology North Bangkok King Mongkut’s Institute of Technology Ladkrabang The Engineering Institute of Thailand Under H.M. The King's Patronage

Sponsored by

LPN Plate Mill PCL Co., Ltd Thai Parkerizing Co., Ltd Thai Tech Steel (2003) Co., Ltd Sahaviriya Steel Industries PCL. Chieng Sang Textile Industries Co., Ltd S. Y. K. Factory and Products Co., Ltd Sammitr Motors Manufacturing Public Company Limited Toyota Boshoku Asia Co., Ltd The Engineering Institute of Thailand Under H.M. The King's Patronage


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Organizing Committees

Conference Chairman Assoc. Professor Dr. Booncharoen Sirinaovakul Dean of Faculty of Engineering, King Mongkut,s University of Technology Thonburi

Committee Mr. Wikom Vajragupta Iron and Steel Institute of Thailand Assoc. Prof. Dr. Weerasak Udomkichdacha National Metal and Materials Technology Center Assoc. Prof. Dr. Gobboon Faculty of Engineering, Chulalongkorn University Asst. Prof. Dr. Ekgasit Nisaratanaporn Metallurgy and Materials Science Research Institute, Chulalongkorn University Mr. Wiroj Sirithanasart Thai Tool and Die Industry Association Assoc. Prof. Dr. Dech Budcharoentong Dean of Faculty of Science, King Mongkut,s University of Technology Thonburi Asst. Prof. Chulsiri Sringaphong King Mongkut,s University of Technology Thonburi

Technical Committee

Assoc. Prof. Dilok Sriprapai Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Assoc. Prof. Dr. Surasak Suranuntchai Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Assoc. Prof. Dr. Varunee Premanond Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Sutasn Thipprakmas Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr.Karuna Toojinda Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Manisara Phiriyawirut Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Jirapoprn Eachalitanukul Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Kusol Prommul Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Surasit Rojananan Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Ratchanee Hato Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Sirinthorn Thongsang Faculty of Engineering, King Mongkut’s University Of Technology Thonburi


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Ms. Onnjira Deawwanich) Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Mr. Noppadol Kumanuvong Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Assoc Prof. Dr. Pongpan Kaewtatip Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Anak Khantachawana Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Bovornchok Poopat Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Sombun Charoenvilaisiri Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Assoc. Prof. Dr. Chaowalit Limmaneevichitr Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Pongsak Thungsuk Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Dr. Paiboon Chuangthong Faculty of Engineering, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Siriporn Rojananan School of Energy, Envelopment and Materials, King Mongkut’s University Of Technology Thonburi Dr. Nuchthana Poolthong School of Energy, Envelopment and Materials, King Mongkut’s University Of Technology Thonburi Asst. Prof. Dr. Ekasit Nisarattanapron Faculty of Engineering, Chulalongkorn University Assoc. Prof. Dr. Prasong Sricharoenchai Faculty of Engineering, Chulalongkorn University Asst. Prof. Dr. Sawai Danchaivijit Faculty of Engineering, Chulalongkorn University Asst. Prof. Dr. Itthipon Diewwanit Faculty of Engineering, Chulalongkorn University Asst. Prof. Dr. Charkorn Jarupisitthorn Faculty of Engineering, Chulalongkorn University Dr. Seksak Asavavisithchai Faculty of Engineering, Chulalongkorn University Dr. Thachai Haengwaranant Faculty of Engineering, Chulalongkorn University Mr. Suvanchai Pongsugitwat Faculty of Engineering, Chulalongkorn University Dr. Patama Visuttipitukul Faculty of Engineering, Chulalongkorn University Dr. Mawin Supradit Na Ayuthaya Faculty of Engineering, Chulalongkorn University Dr. Panyawat Wangyao Faculty of Engineering, Chulalongkorn University Dr. Yutthanant Boonyongmaneerat Metallurgy and Materials Science Research Institute, Chulalongkorn University Dr. Nattita Chuankerikkul Metallurgy and Materials Science Research Institute, Chulalongkorn University Ms. Kanokwan Saengkiettiyut Metallurgy and Materials Science Research Institute, Chulalongkorn University Assoc. Prof. dr. Paritat Pantubanyong


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National Science and Technology Development agency Dr. Julathep Kajornchaiyakul National Metal and Materials Technology Center Dr. Anchalee Manonukul National Metal and Materials Technology Center Dr.Ruangdaj Tongsri National Metal and Materials Technology Center Dr. Ekgarat Wiyanit National Metal and Materials Technology Center Dr. Usanee Kitkamthorn Faculty of Engineering, Suranaree University Dr. Tapany Udomphol Faculty of Engineering, Suranaree University Dr. Pornwasa Wongpanya Faculty of Engineering, Suranaree University Asst. Prof. Dr. Sureerat Polsilapa Faculty of Engineering, Kasetsart University Dr. Patiphan Juijerm Faculty of Engineering, Kasetsart University Asst. Prof. Dr. Somrerk Chandra-ambhorn King Mongkut’s University of Technology North Bangkok Dr. Nattapong Sornsuwit King Mongkut’s University of Technology North Bangkok Assoc. Prof. Pornsak Attavanich Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang Dr. Sutha Sutthiruangwong , Science Faculty Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang Dr. Jessada Wannasin Prince of Songkla University Dr. Saisamorn Niyomsaruan Burapha University Asst. Prof. Dr. Soranat Rhaipu Faculty of Engineering, Mahidol University Assoc. Prof. Dr. Chaosuan Kanchanomai Faculty of Engineering, Thammasart University Assoc. Prof. Dr. Chatchai Somsiri Thainox stainless sPublic Company Limited


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Technical Program

October 16, 2008 Time / Room Grand Ballroom 08:30 - 09:00 Registration 09:00 – 09:30 Opening Ceremony

By Prof. Dr. Chaivat Toskulkao Deputy Permanent Secretary

Ministry of Science and Technology

Welcome address By

Assoc. Prof. Dr. Booncharoen Sirinaovakul Dean of Faculty of Engineering, King Mongkut's University of Technology Thonburi

and Award for Young Outstanding Metallurgist and Thailand Metallurgist of the Year

09:30 – 10:00 Special Lecture “Metallurgy in the Development of Thailand”

Mr. Khemadhat Sukondhasingha Chief Executive Officer Sikor Group of Companies

10:00 – 10:40 Keynote Lecture 1 “Research Development of TiNi-base Shape Memory Alloys”

Prof. Dr. Shuichi Miyazaki Institute of Materials Science, University of Tsukuba, Japan

10:40 – 11:00 Refreshment 11:00 – 11:30 Invited Lecture 1

“Metal Forming with Semi-Solid Casting Process” Dr. Jessada Wannasin

Department of Mining and Materials Engineering, Faculty of Engineering, Prince of Songkla University

11:30 – 12:00 Invited Lecture 2 “TRD Application on Tool Steels”

Assoc. Prof. Dr Prasonk Sricharoenchai Department of Metallurgical Engineering,

Faculty of Engineering, Chulalongkorn University 12:00 – 12:30 Invited Lecture 3

“Finite Element Application in Metal Work” Asst. Prof. Dr. Wiroj Limtrakarn

Department of Mechanical Engineering, Faculty of Engineering, Thammasat University

12:30 – 13:30 Lunch 13:30 – 14:10 Keynote Lecture 2

“Forming and Processing Parameter Effect on Metal Properties” Prof. Dr. Kazunari Yoshida

School of Engineering, Tokai University, Japan 14:10 – 14:40 Invited Lecture 4

“Hardening of Tool Steels in Vacuum Furnaces” Assoc. Prof. Somnuk Watanasriyakul Department of Production Engineering,

Faculty of Engineering, King Mongkut’s University of Technology North Bangkok

Time / Room

Grand Ballroom Ayutthaya 1 Structure Session 1

Session Chair: Asst. Prof. Dr. Ekasit Nisaratanaporn, Metallurgy and Materials Science Research Institute, Chulalongkorn University

Application Session 1 Session Chair: Assoc. Prof. Dr. Varunee Premanond, Department of Tool and Materials Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi


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Session Asst: Dr. Manisara Phiriyawirut (KMUTT) Committee: Asst. Prof. Dr. Anak Khantachawana (KMUTT) Dr. Panyawat Wangyao (CU) Dr. Ratchanee Hato (KMUTT) Dr. Patama Visuttipitukul (CU) Dr. Preecha Termsuksawad (KMUTT)

Session Asst: Ms. Onnjira Diewwanit (KMUTT) Committee: Assoc. Prof. Dr. Pongpan Kaewtatip (KMUTT) Dr. Seksak Asavavisithchai (CU) Dr. Tapany Udomphol (SUT) Dr. Yuttanant Boonyongmaneerat (MMRI) Dr. Kusol Prommul (KMUTT)

14:40 – 15:00 A-01 : Effects of chemical Composition on Microstructure of Batch Annealed AISI 430 N. Thaweepornkhasemsukh Thainox Stainless Public Company Limited

D-01 : Nickel Thin Plate Forming for Microsensor Leadframe Production O. Trithaveesak, P. Choungthong Thai Microelectronics Center, NECTEC

15:00 – 15:20 A-02 : Electron Microscopy for Cast Metals T. Chairuangsri, A. Wiengmoon, N. Poolthong, S. Rojananan, A. Nisarattanaporn, J. Kajornchaiyakul, C. Thanachayanont, J. T. H. Pearce Department of Industrial Chemistry and the Electron Microscopy Research and Service Center, Faculty of Science, Chiang Mai University

D-02 : Modelling the Particulate Reinforced Metal Matrix Composites under Forward Bar Extrusion Using Finite Element Method S. Suranuntchai , P. Kritboonyarit Tool and Materials Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi

15:20 – 15:40 Refreshment Grand Ballroom Ayutthaya 1

Time / Room Properties Session 1 Session Chair: Assoc. Prof. Dr. Gobboon Lothongkum, Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University Session Asst: Dr. Chiraporn Auechalitanukul (KMUTT) Committee: Assit. Dr. Siriporn Rojananan(KMUTT) Dr. Sutha Sutthiruangwong (KMITL) Dr. Patipan Jiijerm (KU) Dr. Karuna Toojinda (KMUTT) Ms. Kanokwan Saengkiettiyut (MMRI)

Processing Session 1 Session Chair: Assoc. Prof. Dilok Sriprapai, Department of Tool and Materials Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi Session Asst: Asst. Prof. Dr. Sutasn Thipprakmas (KMUTT) Committee: Dr. Ruangdaj Tongsri (MTEC) Dr. Nutthita Chuankrerkkul (MMRI) Dr. Somrerk Chandra-Ambhorn (KMITNB) Dr. Nuttaphong, Sornsuwit (KMITNB) Mr Noppadol Kumanuvong (KMUTT)

15:40 – 16:00 C-01 : Production of SG-Si and SG-Al Cast Iron and Comparison of Their Properties M.M. Haque, S. K. Shahaม Ahmad F. Ismail Department of Manufacturing and Materials Engineering, Kulliyyah of Engineering International Islamic University Malaysia

B-01 : Low Sintering Temperature Silver Clay W. Sroisuriya, C. Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

16:00 – 16:20 C-02 : On the Strength of Dissimilar Metals Joint between Magnesium Alloys and Aluminum Alloys

R. Borrisutthekul Suranaree University of Technology

B-02 : Synthesis of Dual Color Gold Nanoparticles P. Pienpinijtham, C. Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

16:20 – 16:40 C-03 : Welding Residual Stresses in Two Competing Single V-Butt Joints P. Wongpanya School of Metallurgical Engineering, Suranaree University of Technology

B-03 : Material Separation of AlMMC by Using Cake Filtration Mechanism N. Nicom, N. Ponsena, A. Rayabsri, T. Puthikitakawiwong, H. Nomura Department of Physics, Faculty of Science, Mahasarakham University


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16:40 – 17:00 C-04 : Mechanical Properties of Beta Titanium Alloys for Biomaterials P.Thiangpak, S. Rojananan, S. Rojananan Division of Materials Technology, School of Energy , Environment and Materials King Mongkut’s University of Technology Thonburi

B-04 : Development of SS400 Dual Phase Steel C. Duengkratok, S. Chandra-Ambhorn, W. Eidhed Materials and Metallurgical Engineering Programme, King Mongkut’s University of Technology North Bangkok

Time / Room Grand Ballroom17:00 – 18:00 Refreshment

and Poster Session Ayutthaya 2-4

18:00 – 20:30 Dinner

October 17, 2008

Time / Room Grand Ballroom 09:00 – 10:00 Invited Lecture 5

“Galvanized Reinforcing Steel for Concrete Structures” Assoc. Prof. Dr. Satian Niltawach

Padaeng Industry Public Company Limited

Time / Room

Grand Ballroom Ayutthaya 1 Processing Session 2

Session Chair: Asst. Prof. Wisit Locharoenrat, Department of Materials Engineering, Faculty of Engineering, Kasetsart University Session Asst: Asst.Prof.Dr. Sutasn Thipprakmas (KMUTT) Committee: Asst. Prof. Dr. Sombun Charoenvilaisiri KMUTT Asst. Prof. Dr. Soranat Rhaipu (MU) Dr. Rattana Borrisutthekul (SUT) Dr. Saisamorn Niyomsuan (BUU) Mr Noppadol Kumanuvong (KMUTT)

Structure Session 2 Session Chair: Assoc. Prof. Dr. Turranin Chairuangsri, Department of Industrial Chemistry and the Electron Microscopy Research and Service Center, Faculty of Science, Chiang Mai University Session Asst: Ms. Onnjira Diewwanit (KMUTT) Committee: Asst. Prof.Dr. Anak Khantachawana (KMUTT) Asst. Prof.Dr. Sureerat polsilapa (KU) Dr. Ratchanee Hato (KMUTT) Mr. Suvanchai Pongsugitwat (CU) Dr. Preecha Termsuksawad (KMUTT)

10:00 – 10:20 B-05 : Effects of Heat Treatment on Dry Wear and Corrosion Properties of 18wt%Cr-3wt%C-6.7wt%Mo Cast Iron A. Wiengmoon, T. Chairuangsri, J.T.H. Pearce . Department of Physics, Faculty of Science, Naresuan University

A-03 : Failure of the aluminum die casting parts: Case study S.Kaewkumsai, S. Uamparn, A. Chianpairot National Metal and Materials Center

10:20 – 10:40 B-06 : Picklability of Thermal Oxide Scales on Carbon Steel in Hot Rolling Line: Effect of Coiling Temperature S. Chandra-ambhorn, W. Thanatepolake , S. Thanateburapasap , S. Intarasakda , S. Iamsupapong Department of Materials Engineering and Production Technology, King Mongkut’s University of Technology North Bangkok

A-04 : Grain Refinement of 7075 Al-Alloy by Thermomechanical Treatment K. Runruksa, P. Srichandr Division of Materials Technology, School of Energy , Environment and Materials King Mongkut’s University of Technology Thonburi

10:40 – 11:00 Refreshment 11:00 – 11:20 B-07 : Effect of Process Parameters of Cooling

Plate Technique on Microstructure of Semi-Solid Aluminum Alloy A. Pirunsarn, N. Poolthong, P. Srichandr Division of Materials Technology, School of Energy, Environment and Materials, King Mongkut’s University of Technology Thonburi

A-05 : On the relationship between specimen thickness and graphite morphology of compacted graphite cast iron (CGI) T. Kumma, K. Teeratatpong, A. Sritong, N. Liamdee, T. Udomphol Suranaree University of Technology


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11:20 – 11:40 B-08 : Semi-Solid Aluminum Alloy Produced by Cooling Plate Rheo-diecasting Process N. Poolthong, C.t Koompai, W. Jirattiticharoean, A. Rengsomboon, K. Srimuang, S. Yupa Division of Materials Technology, School of Energy, Environment and Materials, King Mongkut’s University of Technology Thonburi

A-06 : Size and Distribution of Primary Silicon in Semi-Solid State of A390 Aluminum Alloy Subject to Mechanical Vibration P. Senthongkaew, N. Poolthong, C.Limmaneevichitr Division of Materials Technology, School of Energy, Environment and Material, King Mongkut’s University of Technology Thonburi

11:40 – 12:00 B-09 : Evaluation and Control of Steel Cleanliness by Infrared Spectroscopy A. Mahasaksawat, L. Amonkitbamrung, C. Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

A-07 : Powder Metallurgy of Silver Nanoparticles for Jewelry Making P. Thongnopkun, W. Sroisuriya, S. Ekgasit

Faculty of Gems (Chanthaburi), Burapha University

12:00 – 12:20 B-10 : Influences of Ironing ratio on Phase Transformations of Ni-Ti SMAs plate A. Phukaoluan, A. Khantachawana, P. Kaewtatip, V. Premanond Department of Mechanical Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi,Bangkok

12:20 – 13.20 Lunch

Time / Room

Grand Ballroom Ayutthaya 1 Properties Session 2

Session Chair: Dr. Pongsak Tuengsook Department of Industrial Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi Session Asst: Dr. Chiraporn Auechalitanukul (KMUTT) Committee: Asst. Dr. Siriporn Rojananan(KMUTT) Asst. Prof. Dr. Itthipon Diewwanit(CU) Dr.-Ing. Pornwasa Wongpanya (SUT) Dr. Karuna Toojinda (KMUTT) Dr.-Ing. Paiboon Choungthong (KMUTT)

Application Session 2 Session Chair: Assoc. Prof. Dr. Surasak Suranuntchai, Department of Tool and Materials Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi Session Asst: Dr. Manisara Phiriyawirut (KMUTT) Committee: Assoc. Prof. Dr. Pongpan Kaewtatip (KMUTT) Dr. Tachai luangvaranunt (CU) Dr. Sirinthorn Thongsang (KMUTT) Dr. Usanee Kitkamthorn (SUT) Dr. Kusol Prommul (KMUTT)

13:20 – 13:40 C-05 : Effects of Surface Pretreatment in Hot Dip Galvanizing Process Y. Boonyongmaneerat, P. Rattanawaleedirojn, K. Saenkiettiyut,C.Angkaprasert, N. Chuankrerkkul Metallurgy and materials Science Research Institute, Chulalongkorn University

D-03 : Surface Modification of Pearls with Metal Nanoparticles T. Parnklang, C.Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

13:40 – 14:00 C-06 : Extraction of Mechanical Properties of DLC Films: A Finite Element Analysis N. Panich, P. Wangyao, N. Vattanaprateep , P. VisuttipP. Sricharoenchai Center of Innovative Nanotechnology, Chulalongkorn University

D-04 : Continuous Synthesis of high Concentration Colloidal Silver Nanoparticles P. Maneewattanapinyo, N. Pimpha, C. Thammacharoen. Sanong Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

14:00 – 14:20 C-07 : Determination of Yield Behaviour of Boron Alloy Steel at High Temperature J. Tungtrongpairoj, V. Uthaisangsuk, W. Bleck Materials and Metallurgical Engineering Programme, King Mongkut’s University of Technology North Bangkok

D-05 : Room Temperature Sintered Conductive Silver Ink C. Lertvachirapaiboon, C. Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University


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14:20 – 14:40 C-08 : The Study of Oil Impregnation Effect on Powder Metallurgy Tin Bronze Wear Behavior by Pin-On-Disk Method T. Chotibhawaris, T.Laungwaranunt, S. Charoenvilaisiri King Mongkut’s University of Technology Thonburi,Bangkok

D-06 : Polymer Coating with an Antibacterial Property through the Incorporation of Silver Nanoparticle for Ambulance P. Sonprasit, C. Thammacharoen, S. Ekgasit Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University

14:40 – 15:00 C-09 : The comparison between the properties of various commercial NiTi arch wires used in orthodontics R. Isarapatanapong, S. Dechkunakorn, N. Anuwongnukroh, J. kajornchaiyakul, A. Khantachawana, A. Phukaoluan Department of Orthodontics, Faculty of Dentistry, Mahidol University

D-07 : The Antimicrobial Action of Silver Foams A. Oonpraderm, U. Ruktanonchai, S. Asavavisithchai Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University

15:00 – 15:20 Refreshment Time / Room Grand Ballroom15:20 – 15:50 Invited Lecture 6

“Role of Metallurgies in the Development of Thailand” Asst. Prof. Dr. Panya Srichandr

Division of Materials Technology, School of Energy , Environment and Materials King Mongkut’s University of Technology Thonburi

15:50 – 16:20 Award Presentation for “The Best Oral and Poster Presentation” of each session Closing ceremony by

Assoc. Prof. Dr. Booncharoen Sirinaovakul Dean of Faculty of Engineering, King Mongkut's University of Technology Thonburi

Remark:

Invited Poster Presentations PI-01 Development of microtube for painless microneedle

Kazuyoshi TSUCHIYA school of Engineering Department of Precision Engineering, Tokai University, Japan

PI-02 Easy-Release Screw

Kazunari Yoshida School of Engineering, Tokai University, Japan

PI-03 Development of Magnesium Alloy Sheets by New Twin-Roll Casting System

GONDA METAL INDUSTRY Co.,Ltd. PI-04 Magnesium Alloy AZ61 Sheet

GONDA METAL INDUSTRY Co.,Ltd


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Poster Presentations

P-01 Green Binder System for Powder Injection Moulding N. Chuankrerkkul Metallurgy and Materials Science Research Institute, Chulalongkorn University

P-02 Interfacial Microstructures and Solder Joint Strength of Sn- 3.0 wt.%Ag-0.5wt.%Cu Lead-

free Solder Balls on Ni/Au Finished Printed Circuit Boards O. Diewwanit, N. Tantivanitchanon, S. Sirimethanon Department of Tool and Materials Engineering, King Mongkut’s university of Technology Thonburi, Bangkok

P-03 Zinc Phosphating on Aluminium Plate Using Ni as Catalyst and Post-treatment by Sodium

Silicate S. Dech-Oup, T. Chairuangsri Department of Industrial Chemistry, Faculty of Science, Chiang Mai University

P-04 Morphology and Optical Properties of Copper Nanoparticles Prepared by Pulsed Laser

Ablation in Distilled Water P. Pimpang, H. Lin Aye, T. Chairuangsri, S. Choopun Department of Industrial Chemistry, Faculty of Science, Chiang Mai University

P-05 Failure due to Hydrogen Embrittlement of Cap-Screw Bolt

S. Kaewkumsai, S. Sorachot, W. Khonraeng National Metal and Material Technology Center (MTEC)

P-06 Stress Corrosion Cracking in Welded 316SS Screener Shaft

S. Kaewkumsai, S. Aumparn, E. Viyanit National Metal and Material Technology Center (MTEC)

P-07 Galvanic Corrosion induced Failure of Ceiling Suspension

S. Kaewkumsai, W. Khonraeng, A. Chianpairot National Metal and Material Technology Center (MTEC)

P-08 A Feasibility Study of Silver Recovery from a Waste in Zinc-Ore-Hot-Acid Leaching Process

W. Prasong, T. Chairuangsri Department of Industrial Chemistry, Faculty of Science, Chiang Mai University

P-09 Corrosion Resistance of Hot-Dip Galvanized Steels in Saline and Swine Urine Environments

K. Saengkiettiyut, C. Angkaprasert, P. Rattanawaleedirojn, S. Saenapitak, A. Thueploy, Jumpot Wanichsampan, S. Lisnunt, N. Chuankrerkkul, Y. Boonyongmaneerat Metallurgy and Materials Science Research Institute, Chulalongkorn University

P-10 Acceptable TIG-Pulse Welding Parameters of AISI 304L Stainless Steels at 8-h Welding Position N. Sornsuwit , S. Chandra-ambhorn Department of Materials Engineering and Production Technology, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok (KMUTNB)


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Content

Keynote Lectures

K-01 Research Development of TiNi-base Shape Memory Alloys 17 S. Miyazaki

K-02 Drawability Improvement of Titanium Wire and Fabrication of 18 Microparts of medical applications

K. Yoshida

Invited Lectures

I-01 Metal Forming with Semi-Solid Casting Process” 20 J. Wannasin

I-02 TRD application on Tool Steels 21 P. Sricharoenchai

I-03 Finite Element Application in Metal Work 22

W. Limtrakarn

I-04 Hardening of Tool Steels in Vacuum Furnaces 23 S. Watanasriyakul

I-05 Galvanized Reinforcing Steel in Concrete Structures 24

S. Niltawach Oral Presentations Structures Session

A-01 Effects of chemical Composition on Microstructure of Batch Annealed 26 AISI 430 N. Thaweepornkhasemsukh A-02 Electron Microscopy for Cast Metals 29

T. Chairuangsri, A. Wiengmoon, N. Poolthong, S. Rojananan, A. Nisarattanaporn, J. Kajornchaiyakul, C. Thanachayanont, J. T. H. Pearce

A-03 Failure of the aluminum die casting parts: Case study 31

S.Kaewkumsai, S. Uamparn, A. Chianpairot

A-04 Grain Refinement of 7075 Al-Alloy by Thermomechanical Treatment 35 K. Runruksa, P. Srichandr

A-05 On the relationship between specimen thickness and graphite morphology 39 of compacted graphite cast iron (CGI)

T. Kumma, K. Teeratatpong, A. Sritong, N. Liamdee, and T. Udomphol

A-06 Size and Distribution of Primary Silicon in Semi-Solid State of A390 41 Aluminum Alloy Subject to Mechanical Vibration

P. Senthongkaew, N. Poolthong, C. Limmaneevichitr

A-07 Powder Metallurgy of Silver Nanoparticles for Jewelry Making 44 P. Thongnopkun, W. Sroisuriya , S. Ekgasit


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Processing Session

B-01 Low Sintering Temperature Silver Clay 47 W. Sroisuriya, C. Thammacharoen, S. Ekgasit

B-02 Synthesis of Dual Color Gold Nanoparticles 49

P. Pienpinijtham, C. Thammacharoen, S. Ekgasit B-03 Material Separation of AlMMC by Using Cake Filtration Mechanism 51

N. Nicom, N. Ponsena, A. Rayabsri, T. Puthikitakawiwong, H. Nomura

B-04 Development of SS400 Dual Phase Steel 53 C. Duengkratok, S. Chandra-Ambhorn, W. Eidhed

B-05 Effects of Heat Treatment on Dry Wear and Corrosion Properties of 56 18wt%Cr-3wt%C-6.7wt%Mo Cast Iron

A. Wiengmoon, T. Chairuangsri, J.T.H. Pearce .

B-06 Picklability of Thermal Oxide Scales on Carbon Steel in Hot Rolling Line: 58 Effect of Coiling Temperature

S. Chandra-ambhorn, W. Thanatepolake , S. Thanateburapasap , S. Intarasakda , S. amsupapong

B-07 Effect of Process Parameters of Cooling Plate Technique on 60 Microstructure of Semi-Solid Aluminum Alloy

A. Pirunsarn, N. Poolthong, P. Srichandr B-08 Semi-Solid Aluminum Alloy Produced by Cooling Plate Rheo-diecasting 62 Process

N. Poolthong, C. Koompai, W. Jirattiticharoean, A. Rengsomboon, K. Srimuang, S. Yupa

B-09 Evaluation and Control of Steel Cleanliness by Infrared Spectroscopy 64

A. Mahasaksawat, L. Amonkitbamrung, C. Thammacharoen, S. Ekgasit

B-10 Influences of Ironing ratio on Phase Transformations of Ni-Ti SMAs plate 66 A. Phukao luan, A. Khantachawana, P. Kaewtatip, V. Premanond

Properties Session

C-01 Production of SG-Si and SG-Al Cast Iron and Comparison of Their 69 Properties M. M. Haque, S. K. Shaha and A. F. Ismail C-02 On the Strength of Dissimilar Metals Joint between Magnesium Alloys and 73 Aluminum Alloys

R. Borrisutthekul C-03 Welding Residual Stresses in Two Competing Single V-Butt Joints 75

P. Wongpanya

C-04 Mechanical Properties of Beta Titanium Alloys for Biomaterials 82 P.Thiangpak, S. Rojananan, S. Rojananan

C-05 Effects of Surface Pretreatment in Hot Dip Galvanizing Process 84

Y. Boonyongmaneerat, P. Rattanawaleedirojn,


-14-

K. Saenkiettiyut,C.Angkaprasert, N. Chuankrerkkul C-06 Extraction of Mechanical Properties of DLC Films: 87 A Finite Element Analysis N. Panich, P. Wangyao, N. Vattanaprateep , P. Visuttipitukul, P. Sricharoenchai C-07 Determination of yield behaviour of boron alloy steel at high temperature 90

J. Tungtrongpairoj, V. Uthaisangsuk, W. Bleck C-08 The Study of Oil Impregnation Effect on Powder Metallurgy Tin Bronze 97 Wear Behavior by Pin-On-Disk Method

T. Chotibhawaris, T.Laungwaranunt, S. Charoenvilaisiri

C-09 The comparison between the properties of various commercial NiTi arch 100 wires used in orthodontics

R. Isarapatanapong, S. Dechkunakorn, N. Anuwongnukroh, J. kajornchaiyakul, A. Khantachawana, A. Phukaoluan

Application Session D-01 Nickel Thin Plate Forming for Microsensor Leadframe Production 107 O. Trithaveesak, P. Choungthong D-02 Modelling the Particulate Reinforced Metal Matrix Composites under 109 Forward Bar Extrusion Using Finite Element Method

S. Suranuntchai , P. Kritboonyarit D-03 Surface Modification of Pearls with Metal Nanoparticles 114 T. Parnklang, C.Thammacharoen, S. Ekgasit

D-04 Continuous Synthesis of high Concentration Colloidal Silver Nanoparticles 116 P. Maneewattanapinyo, N. Pimpha, C. Thammacharoen. Sanong Ekgasit

D-05 Room Temperature Sintered Conductive Silver Ink 118

C. Lertvachirapaiboon, C. Thammacharoen, S. Ekgasit D-06 Polymer Coating with an Antibacterial Property through the 120 Incorporation of Silver Nanoparticle for Ambulance

P. Sonprasit , C. Thammacharoen, S. Ekgasit D-07 The Antimicrobial Action of Silver Foams 122

A. Oonpraderm, U. Ruktanonchai and S. Asavavisithchai Poster Presentations

P-01 Green Binder System for Powder Injection Moulding 125

N. Chuankrerkkul P-02 Interfacial Microstructures and Solder Joint Strength of 127 Sn- 3.0 wt.%Ag-0.5wt.%Cu Lead-free Solder Balls on Ni/Au Finished Printed Circuit Boards

O. Diewwanit, N. Tantivanitchanon, S. Sirimethanon

P-03 Zinc Phosphating on Aluminium Plate Using Ni as Catalyst and 129 Post-treatment by Sodium Silicate

S. Dech-Oup, T. Chairuangsri


-15-

P-04 Morphology and Optical Properties of Copper Nanoparticles Prepared 131 by Pulsed Laser Ablation in Distilled Water

P. Pimpang, H. Lin Aye, T. Chairuangsri, S. Choopun

P-05 Failure due to Hydrogen Embrittlement of Cap-Screw Bolt 133 S. Kaewkumsai, S. Sorachot, W. Khonraeng

P-06 Stress Corrosion Cracking in Welded 316SS Screener Shaft 134

S. Kaewkumsai, S. Aumparn, E. Viyanit P-07 Galvanic Corrosion induced Failure of Ceiling Suspension 139

S. Kaewkumsai, W. Khonraeng, A. Chianpairot

P-08 A Feasibility Study of Silver Recovery from a Waste in Zinc-Ore-Hot-Acid 142 Leaching Process

W. Prasong, T. Chairuangsri

P-09 Corrosion Resistance of Hot-Dip Galvanized Steels in Saline and Swine 144 Urine Environments

K. Saengkiettiyut, C. Angkaprasert, P. Rattanawaleedirojn, S. Saenapitak, A. Thueploy, J. Wanichsampan, S. Lisnunt, N. Chuankrerkkul, Y. Boonyongmaneerat

P-10 Acceptable TIG-Pulse Welding Parameters of AISI 304L Stainless Steels 147 at 8-h Welding Position

N. Sornsuwit , S. Chandra-ambhorn

Keynote Lectures


-17-

Research Development of TiNi-base Shape Memory Alloys

Shuichi Miyazaki Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

ABSTRACT-Ti-Ni alloys have been investigated since the first report on shape memory effect (SME) in a Ti-Ni alloy in 1963. However, the Ti-Ni alloys had presented many difficult problems with many puzzling phenomena for about 20 years until 1982 when the basic understanding was established on the relationship between the microstructure and the corresponding deformation behavior such as SME and superelasticity (SE). Since then, many puzzling phenomena have been clarified: e.g., the microstructures which cause the rhombohedral phase (R-phase) transformation to appear, the orientation dependence of shape memory and superelastic behavior observed in single crystals, the temperature dependence of deformation and fatigue behavior, the shape memory mechanism, etc. The history of the development of Ti-Ni alloys will be surveyed.

The Ti-Ni alloys have been successfully applied for many products both in engineering and medical fields since 1982. Some of these applications will be shown in the present talk. For further expanding the application market, new types of shape memory alloys are required, e.g., high temperature shape memory alloys (SMAs), thin film SMAs, Ni-free Ti SMAs, etc. Recent development of these new alloys is also reviewed. .


-18-

Drawability Improvement of Titanium Wire and Fabrication of Microparts of medical applications

Kazunari Yoshida Department of Precision Engineering, School of Engineering, Tokai University

1117 kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan, [email protected]

ABSTRACT-Titanium has great advantages, such as nontoxicity and high biocompatibility. Recently, it has begun to be used with high expectations in the medical field, such as for fabricating guide wire, orthodontic wires and microparts of medical appliances. However, because the plastic workability of Titanium is inferior to that of other metals, there is difficulty in manufacturing Titanium products, such as extrafine wires and microscrews, without cracks and other defects. Moreover, although the effects of small amounts of O and N in a pure Ti wire on its mechanical properties have been discussed, the effects on plastic workability, such as drawability, have not been clarified yet. In this study, we examined the effects of the amounts of O and N on workability and product strength during drawing, heading and rolling, and clarified the optimal conditions for cold drawing. We can infer the magnitude of the drawing limit on the basis of the break strain of mother wire. The fabrication of the guide wire, microspring and microscrews in medical fields as an application of the obtained drawn wire are also targeted in this study. The fabrications of these products were found possible by the metal forming which is selected an appropriate conditions.


-19-

Invited Lectures


-20-

Metal Forming with Semi-Solid Casting Process การขึ้นรูปโลหะโดยกระบวนการ Semi-Solid Casting

ดร. เจษฎา วรรณสินธุ

ทีมวิจัยโลหะกึ่งของแข็ง ภาควิชาวิศวกรรมเหมืองแรและวัสดุ มหาวิทยาลัยสงขลานครินทร อ. หาดใหญ จ. สงขลา 90112

การขึ้นรูปโลหะในอุตสาหกรรมการผลิตชิ้นสวนตางๆในประเทศไทยโดยทั่วไปแบงไดเปน 2 กรรมวิธีหลักๆ คือ การขึ้นรูปในสถานะของแข็ง เชน การทุบขึ้นรูป (Forging) และการขึ้นรูปในสถานะของเหลว เชน การหลอ (Casting) โดยทั้งสองกรรมวิธีนี้ตางมีขอดีและขอดอยทําใหเหมาะกับการผลิตชิ้นงานโลหะตางกนั ช้ินงานที่ผลิตจากการทุบขึ้นรูปจะมีโครงสรางที่สมบูรณ ปราศจากรูพรุน และมีสมบัติเชิงกลที่สูง แตในการขึ้นรูปตองใชพลังงานที่สูงและเครื่องจักรที่ราคาแพง สวนชิ้นงานที่ผลิตจากการหลอโลหะจะมีตนทุนการผลิตที่ต่ํากวาและมีอัตราการผลิตที่สูงกวา แตสมบัติเชิงกลท่ีไดจะต่ํากวาเนื่องจากโครงสรางที่ไมสมบูรณนัก นอกจากกรรมวิธีการข้ึนรูปหลักทั้ง 2 ที่กลาวมานี้ยังมีอีกกรรมวิธีท่ีกําลังใชในการผลิตในตางประเทศ น่ันคือ การขึ้นรูปโลหะในสถานะกึ่งของแข็ง ซึ่งหมายถึง โลหะในขณะการขึ้นรูปมีสวนที่เปนของแข็งและสวนท่ีเปนของเหลวผสมอยู ทําใหในการขึ้นรูปไมจําเปนตองใชแรงและพลังงานมากเทากับการทุบขึ้นรูปจึงทําใหมีตนทุนการผลิตที่ต่ํากวา นอกจากนี้โครงสรางของชิ้นงานที่ผลิตไดมีความสมบูรณมากกวาการหลอ ทําใหสมบัติเชิงกลที่ไดมีคาสูงกวา ในการบรรยายพิเศษน้ีจะกลาวถึงการขึ้นรูปโลหะในสถานะกึ่งของแข็ง การพัฒนาและการนําไปใชจริงในอุตสาหกรรมตางๆในตางประเทศ กระบวนการ Semi-Solid Casting ซึ่งกําลังอยูในชวงวิจัยและพัฒนาโดยทมีวจิยัโลหะกึ่งของแข็ง ที่ภาควิชาวิศวกรรมเหมืองแรและวัสดุ มหาวิทยาลัยสงขลานครินทร รวมถึงโอกาสการนํากระบวนการ Semi-Solid Casting ไปประยุกตใชในอุตสาหกรรมในประเทศไทย


-21-

TRD application on Tool Steels

การเคลือบผิวเหล็กกลาแมพิมพดวยกระบวนการ TRD

รศ.ดร. ประสงค ศรีเจริญชัย ภาควิชาวิศวกรรมโลหการ คณะวิศวกรรมศาสตร จุฬาลงกรณมหาวิทยาลัย

[email protected]

กระบวนการ TRD (Thermo-reactive deposition and diffusion) เปนกระบวนการเคลือบผิวท่ีอุณหภูมิสูงที่ฟอรมชั้นเคลือบแข็งของชั้นคารไบด การเคลือบใชอางเกลือท่ีมีบอแรกซหลอมเหลวโดยเติมสารที่ฟอรมเปนคารไบดในรูปของเฟอรโรอัลลอย หรือรูปของออกไซดรวมกับตัวรีดิวส อุณหภูมิเคลือบแปรผันระหวาง 900-1000oC และแปรผันระยะเวลาเพื่อใหไดความหนาตามที่ตองการ เหล็กกลาแมพิมพที่ใชเคลือบคือเหล็กกลา SKD11, SKD61 และ SKH51 ผลการเคลือบผิวเหล็กกลาแมพิมพดวยกระบวนการ TRD รายงานเปนพารามิเตอรที่ควบคุมความหนาของชั้นเคลือบคารไบด กลาวคือปริมาณสารที่ฟอรมเปนคารไบด ปริมาณคารบอนในเนื้อเหล็กกลา อุณหภูมิที่เคลือบและเวลาที่เคลือบ

ช้ันเคลือบที่นิยมเคลือบดวยกระบวนการ TRD คือช้ันเคลือบวาเนเดยีมคารไบดซ่ึงมคีวามแข็ง 3000 Hv หรือมากกวาจงึใชตานทานการสึกหรอไดด ี อยางไรก็ดช้ัีนเคลือบเชิงซอนวาเนเดียมไนโอเบียมคารไบดท่ีเคลือบดวยกระบวนการเดียวกนันีม้ีความแข็งสูงกวาวาเนเดียมคารไบดจึงอาจใชตานทานการสึกหรอแบบขัดสีไดดีข้ึนอีก


-22-

Finite Element Application in Metal Work

การประยุกตไฟไนตเอลิเมนตในงานทางโลหะ

ผศ. ดร. วิโรจน ลิ่มตระการ คณะวิศวกรรมศาสตร มหาวิทยาลัยธรรมศาสตร

ปจจุบันงานทางโลหะดานการพัฒนานวัตกรรมใหม ๆ หรือ พัฒนาผลิตภัณฑโลหะเดิมใหมีตนทุนการผลิตที่ต่ําลง เปนสวนที่บริษัทจํานวนมากใหความสําคัญและตองการใหเกิดเปนรูปธรรม บางบริษัทเริ่มมีการนําเทคโนโลยีการออกแบบและการผลิตเขามาชวย เพื่อพัฒนาศักยภาพดานการแขงขันของบริษัทใหทัดเทียม หรือ ดีกวาบริษัทคูแขงทั้งภายในประเทศและตางประเทศ ระเบียบวิธีไฟไนตเอลิเมนตเปนเทคโนโลยีการคํานวณทางวิศวกรรมที่ไดรับการยอมรับในวงกวางวามีประสิทธิภาพสูงในดานการประยุกตกับงานทางวิศวกรรมทั้งการออกแบบและผลิต จากความตองการใชงานของกลุมวิศวกรทําใหในปจจุบันมีซอฟแวรไฟไนตเอลิเมนตเกิดขึ้นมาหลายรอยซอฟแวร โดยมีขีดความสามารถในการวิเคราะหผลิตภัณฑโลหะท่ีสรางมาจากโลหะแผนบาง เชน โครงรถยนต เปนตน หรือ กอนโลหะ เชน กานสูบเครื่องยนต เปนตน การประยุกตใชไฟไนตเอลิเมนตไดอยางมีประสิทธิภาพและแขงขันไดเทาทันกับคูแขงนั้น ผูใชจําเปนตองเขาใจในทฤษฎีและแนวคิดการประยุกตระเบียบวิธีไฟไนตเอลิเมนตอยางชัดแจง แลวจึงคอยพัฒนาเทคนิคและประสบการณการประยุกตซอฟแวรไฟไนตเอลิเมนตเขากับผลิตภัณฑ หรือโจทยของตนเองตอไป ดังนั้นการประยุกตไฟไนตเอลิเมนตในงานโลหะ และงานดานอื่น ๆ จึงจําเปนตองพัฒนาคนของบรษิทัขึน้มากอน หลังจากนั้นจะทําใหเกิดผลประโยชนข้ึนกับตัวผูใชเอง รวมถึงบริษัทในระยะยาวไดอยางยั่งยืน


-23-

Hardening of Tool Steels in Vacuum Furnaces

การชุบแข็งเหล็กกลาเครื่องมือในเตาสุญญากาศ

รศ. สมนึก วัฒนศรียกลุ ภาควิชาวิศวกรรมการผลิต คณะวิศวกรรมศาสตร มหาวิทยาลัยเทคโนโลยีพระจอมเกลาพระนครเหนือ

โทรศัพท 029132500-24 ตอ 8203 โทรสาร 025870029 e-mail [email protected]

เหล็กกลาเครื่องมือ (Tool Steels) เปนวัตถุดิบสําคัญในการผลิตเครื่องมือ (Tools) ประเภทตางๆ เชน แมพิมพข้ึนรูป (Forming Die) แมพิมพกดอัด (Extrusion Die) แมพิมพหลอฉีด (Die Casting) ลูกรีด (Roller) แมพิมพตัด (Punch Die) มีดตัด (Shear Blade) ฯลฯ เครื่องมือเหลานี้เมื่อผลิตเสร็จกอนที่จะนําไปใชงานไดตองผานกระบวนการชุบแข็งกอนเสมอ ดังนั้นการชุบแข็งจึงนับวาเปนสวนหนึ่งของกระบวนการผลิตเครื่องมือ โดยทั่วไปผูผลิตเครื่องมือจะไมทําการชุบแข็งเอง เนื่องจากการชุบแข็งใชเทคนิคเฉพาะ และมีผลตอคุณภาพและตนทุนของเครื่องมือโดยตรง สวนใหญจึงนิยมมอบใหผูรับจางชุบแข็งเปนผูดําเนินการ การดําเนินการชุบแข็งเหล็กกลาเครื่องมือปจจุบันนิยมทําในเตาสุญญากาศเนื่องจากมีขอดีดานคุณภาพหลายอยาง เชนความสม่ําเสมอของความแข็งที่ได สภาพผิวช้ินงานที่สะอาด และการเสียรูปต่ํา หลักการทํางานของเตา ช้ินงานจะถูกใหความรอนในหองสุญญากาศจนถึงอุณหภูมิชุบแข็ง จากนั้นจะถูกทําใหเย็นตัวเร็วโดยการฉีดแกสไนโตเจนความดันสูง (max. 12 bar) ทําใหช้ินงานเย็นตัวจนเปลี่ยนโครงสรางสมบูรณภายในเตา เตาสุญญากาศทั้งหมดนําเขาจากตางประเทศสวนใหญจากยุโรป อเมริกาและญี่ปุน ผูเขียนไดรวบรวมจํานวนและตําแหนงที่ตั้งของโรงงานรับจางชุบแข็งเหล็กกลาเครื่องมือ รวมถึงราคาคาชุบแข็ง ซึ่งขอมูลนี้นาจะเปนประโยชนตอผูผลิตเครื่องมือในประเทศ


-24-

Galvanized Reinforcing Steel in Concrete Structures

Assoc. Prof. Dr. Satian Niltawach Padaeng Industry Public Company Limited

[email protected]

ABSTRACT-Black steel as reinforcement for concrete normally lasts a long time, due to the formation of a passive Fe(OH)2 film on the steel surface contacted by wet cement with pH greater than 13. In carbonation, carbonic acid reduces the concrete pH to below 11.5. At this point, a non-protective layer of FeCO3 replaces Fe(OH)2 leaving the unprotected steel to degenerate into rust. Whereas in chloride attack, even if the pH of concrete is above 11.5, chloride ions diffuse inward to attack the Fe(OH)2 film to form FeCl2, which further corrodes to become Fe2O3. The remaining Fe(OH)2 is subsequently wiped out by the rust. Rust has a specific volume 3 times that of steel. The volumetric expansion gives rise to a stress which breaks loose the concrete from the corroded steel. When wet cement contacts zinc on galvanized steel, a tenacious film of calcium hydroxyzincate forms. Apart from giving high bond strength between concrete and the reinforcement, zinc effectively prevents carbonation and chloride attack on the steel. Hence, the working life of concrete structures reinforced with galvanized steel is extended.

Oral Presentations

Structure Session


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Effects of Chemical Composition on Microstructure of Batch Annealed AISI 430

N. Thaweepornkhasemsukh

Thainox Stainless Public Company Limited, Rayong, Thailand Tel. 038-636125 ext. 539, Fax. 038-952125, E-Mail: [email protected]

ABSTRACT - Observation of hot rolled AISI 430 stainless steel shows ferrite(α) and martensite(α′). It was found that the amount of martensite phase decreased as the ratio of Cr eq / Ni eq content increased. In this experiment, the hot rolled samples were annealed with different ratio of Cr eq / Ni eq at 800°C to 900°C for 1 hour and then water quenched. Area fraction of martensite and hardness of the samples were then characterized with optical microscope (OM) and Rockwell. Correlation between martensite content and chemical composition were analyzed. It can be concluded that as Cr eq / Ni eq ratio increased, the annealing temperature could be increased, so annealing time can be reduced. KEY WORDS -- AISI 430, batch annealing process, chemical composition, microstructure, phase transformation

1. Introduction Microstructure of AISI 430 stainless steel in hot rolled condition consists of ferrite (α) and martensite(α′) streaks in hot rolling direction [1-2]. During hot rolling, the ferrite was transformed to austenite(γ), and when fast cooled the austenite will transform to martensite. The mechanical properties of hot coils were not suitable for cold rolling process. Its properties can be improved by annealing process. The annealing was to dissolve martensite and aid phase transformation to ferrite and chromium carbide (Cr23C6) [1-6]. Its hardness and strength are reduced and that they are suitable for subsequent cold rolling process. As mentioned above, a correlation of phase transformation is connected with chemical composition ratio of Cr eq / Ni eq which determines maximum annealing temperature [1-3]. Because the chemical composition has a great effect to phase transformation from ferrite to austenite, as shown in Figure 1. Because AISI 430 is semi-ferritic stainless steel, it exhibits some austenite phase at high temperature, which can transform to martensite during cooling condition. [1-6] Therefore, maximum annealing temperature is limited to avoid austenite phase occurrences. In this work, the final microstructure are related to variation of ratio of Cr eq / Ni eq with the annealing temperature. Hence, the objective of this work is to make projection of microstructure and hardness with the chemical composition for batch annealing process.

Figure1: Effect of carbon and nitrogen content (wt%) on austenite and ferrite in iron – chromium system [3] 2. Experimental Procedures AISI 430 stainless steel was hot rolled to a thickness of 3 mm and batch annealed. Table 1 shows chemical composition of AISI 430 samples. According to relationship of the effect on phase stabilized, which followed in Schaeffler Diagram [3], as equation 2.1 and 2.2. Table 2 shows the variation ratio of chromium equivalent and nickel equivalent. Cr eq = %Cr + 2%Si + 1.5%Mo + 1.75%Nb

+ 5.5%Al + 5%V + 1.5%Ti + 0.75%W (2.1) Ni eq = %Ni + 0.5%Mn + 30%C + 25%N + 0.3%Cu + %Co (2.2)

γ

α


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Table1: Chemical compositions of AISI 430 (% wt) Samples C N Si Cr Mn Ni Cu Mo

1 0.051 0.047 0.31 16.20 0.36 0.15 0.013 0.01

2 0.046 0.043 0.35 16.01 0.37 0.19 0.024 0.02

3 0.049 0.036 0.40 16.09 0.41 0.16 0.120 0.03

4 0.042 0.042 0.28 16.34 0.33 0.15 0.118 0.03

5 0.040 0.035 0.23 16.16 0.55 0.17 0.076 0.02

6 0.038 0.038 0.32 16.19 0.32 0.14 0.068 0.03

Table2: Cr eq / Ni eq ratio of AISI 430

Samples Cr eq / Ni eq

1 5.54

2 5.90

3 6.11

4 6.37

5 6.55

6 7.00

Batch annealing simulation, specimens were annealed in box furnace at 800°C, 825°C, 850°C, 875°C and 900°C for 1 hour and then quenched. Optical Microscope (OM) was used to investigate and analyze microstructure. Finally, Rockwell hardness test were carried out on all samples. 3. Results and Discussions Hot rolled of AISI 430 microstructure consists of banded structure of ferrite (white) and martensite (dark) oriented in hot rolling direction [1-2], as shown in Figure 2. This structure indicates characteristic of wrought structure. Furthermore, area fraction of martensite in the samples, were found to be approximately 53 - 56 % (Table 3).

Low magnification High magnification Figure 2: Microstructure of AISI 430 in hot rolled condition. After annealed of specimen which has Cr eq / Ni eq ratio of 5.54, the ferrite and chromium carbide (Cr23C6) [1] were found on the microstructures of all condition. Nevertheless, martensite was found on the ferrite matrix after annealing at 850°C, 875°C and 900°C, as shown in Figure 3(a) - (e). First two samples exhibit ferrite and chromium carbide. But when annealing temperature increased to 850°C, the martensite content started to appear on the microstructure.

(a) annealing at 800°C (b) annealing at 825°C

(c) annealing at 850°C (d) annealing at 875°C

(e) annealing at 900°C

Figure3: Microstructures of AISI 430 specimens which Cr eq / Ni eq ratio of 5.54 after annealing conditions for 1 hour and then water cool Figure 4 shows relationship between the Cr eq / Ni eq ratio and annealing temperature on the martensitic transformation. It is noted that these martensitic transformation starts at annealing temperature higher than 850°C. Additionally, the appropriate annealing temperature is depending on the Cr eq / Ni eq ratio, as seen in Figure 1. Figure 4 shows annealing temperature and Cr eq / Ni eq ratio that would not result in martensitic transformation upon water quenched. Table 3 shows area fraction of martensite on these microstructures. The martensite content decreased, with an increase of Cr eq / Ni eq ratio and a decrease in the annealing temperature. From these results, it could be explained that the hardness increased with the martensite formation, as shown in Table 4. The results of hardness were depending on the area fraction of martensite. Finally, it could be summarized that the martensite appearance represents non-suitable annealing condition.

ND

RD

ND

RD

Ferrite Cr23C6

Cr23C6


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Figure4: Effect of Cr eq / Ni eq ratio on martensitic transformation of AISI 430 Table3: Area fraction of martensite phase of AISI 430

Remark: HR is hot rolled sample. Table4: Hardness tests (HRB) of as-annealed samples of AISI 430

Cr eq / Ni eq 800°C 825°C 850°C 875°C 900°C HR

5.54 73.4 72.1 71.9 76.5 81.0 98.6

5.90 73.9 74.1 73.3 75.2 77.6 99.4

6.11 72.5 73.9 73.7 74.6 76.1 98.5

6.37 71.7 71.5 71.0 74.8 73.5 98.6

6.55 72.6 73.4 72.1 72.9 72.4 99.0

7.00 73.1 73.7 72.5 71.6 70.3 98.8

4. Conclusions 1. When Cr eq / Ni eq ratio was high enough, phase

transformation from ferrite to austenite does not occur. As a consequence martensite presence is suppressed.

2. Annealing temperature can be increased for alloys having high Cr eq / Ni eq ratio.

3. Hardness of the annealed product, after quenching can be used as a controlling parameter to indicate proper annealing of the AISI 430 stainless steel.

5. References [1] ASM Handbook, Stainless Steel, 1st edition, USA, 1994. [2] ASM Handbook, Metallography and Microstructures, 1st edition, USA, 1998. [3] J. Beddoes, J. G. Parr, Introduction to Stainless Steel, 3rd edition, USA,1999.

[4] P. Lacombe, B. Baroux and G. Beraner, Stainless Steels, France, 1993. [5] R.E. Reed-Hill and R. Abbaschian, Physical Metallurgy Principles, 3rd edition, USA,1994. [6] G.E. Dieter, Mechanical Metallurgy, 1st edition, Singapore, 1988.


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Electron Microscopy for Cast Metals : Activities at Chiang Mai University

T. Chairuangsri1, A. Wiengmoon2, N. Poolthong3, S. Rojananan3, A. Nisarattanaporn4, J. Kajornchaiyakul5, C. Thanachayanont5, J. T. H. Pearce5

1Department of Industrial Chemistry and the Electron Microscopy Research and Service Center, Faculty of Science, Chiang Mai University (CMU), Chiang Mai, 50200, Thailand

2Department of Physics, Faculty of Science, Naresuan University (NU), Phitsanulok, 65000, Thailand

3Division of Materials Technology, School of Energy, Environmental and Materials, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10140, Thailand

4Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University (CU), Bangkok, 10330, Thailand

5National Metal and Materials Technology Center (MTEC), Bangkok, 10400, Thailand

ABSTRACT - Electron microscopy has been extensively used for structural and compositional analysis of wrought metals. However, less work, especially on transmission electron microscopy, was performed on cast metals due probably to difficulty in sample preparation causing by heterogeneity of the casting structure. Our recent electron microscopy investigations of cast metals including high chromium cast irons, cast aluminium alloy A356, cast duplex stainless steel and cast silver alloy, were reviewed in this article. These research activities have been conducting at the Department of Industrial Chemistry and the Electron Microscopy Research and Service Center (EMRSc), Faculty of Science, Chiang Mai University in collaboration with metallurgy laboratories in other institutes. In addition, because of a potential to be applied in many industrial fields, effects of semi-solid cast process, in which molten alloys are cooled and partially solidified before the shape making operation is performed, has also been studied in comparison to conventional cast process. KEY WORDS -- electron microscopy, cast metals, high chromium cast irons, cast aluminium alloy A356, cast duplex stainless steel, cast silver alloy, semi-solid cast process บทคัดยอ จุลทรรศนศาสตรอิเล็กตรอนถูกใชอยางกวางขวางในการวิเคราะหโครงสราง และองคประกอบเคมีของโลหะรีด อยางไรก็ตาม งานศึกษาทางดานน้ีในโลหะหลอมีนอย โดยเฉพาะจุลทรรศนศาสตรอิเล็กตรอนแบบสองผาน ซึ่งอาจเปนเพราะความยากในการเตรียมชิ้นงานเน่ืองจากความไมเปนเน้ือเดียวของโครงสรางงานหลอ บทความน้ีเปนการทบทวนงานของเราท่ีใชจุลทรรศนศาสตรอิเล็กตรอนศึกษาโลหะหลอ ประกอบดวย เหล็กหลอโครเมียมสูง โลหะผสมอะลูมิเนียมหลอ เอ356 เหล็กกลาไรสนิมดูเพล็กซหลอ และโลหะผสมเงินหลอ งานวิจัยเหลาน้ีไดดําเนินอยู ณ ภาควิชาเคมีอุตสาหกรรม และศูนยวิจัยและบริการจุลทรรศนศาสตรอิเล็กตรอน คณะวิทยาศาสตร มหาวิทยาลัยเชียงใหม ในความรวมมือกับหองปฏิบัติการโลหะวิทยาของสถาบันอ่ืน ๆ นอกจากน้ี เน่ืองจากศักยภาพในการประยุกตกับอุตสาหกรรมตาง ๆ จึงไดศึกษาผลของกระบวนการหลอแบบก่ึงแข็ง ซึ่งโลหะหลอมถกูทําใหเย็นและแข็งตัวบางสวนกอนการขึ้นรูป เปรียบเทียบกับกระบวนการหลอดั้งเดิมดวย คําสําคัญ -- จุลทรรศนศาสตรอิเล็กตรอน, โลหะหลอ, เหล็กหลอโครเมียมสูง, โลหะผสมอะลูมิเนียมหลอ เอ356, เหล็กกลา

ไรสนิมดูเพล็กซหลอ, โลหะผสมเงินหลอ, กระบวนการหลอแบบก่ึงแข็ง 1. Introduction The first part of this paper shows observations of high chromium cast irons in as-cast and different heat-treating conditions. Microstructural modification by semi-solid cast process was also investigated. These irons are of interest because they are relevant to Thai industries e.g. in zinc extraction plant and cement manufacturing. The second part presents an observation of a cast aluminium alloy A356. Alloys in this group are particularly used for aircraft and automotive

applications, e.g. lightweight wheels for sports car. Complexity of aging precipitation sequence has made the precipitation subject in this alloy group remains controversial and hence electron microscopy study of precipitation in this alloy has been motivated. A study of a cast duplex stainless steel is given in the third part. This alloy consist of both ferrite and austenite and is used in some industries relevant to Thailand, e.g. chemical, petrochemical and power industries, due to its superior corrosion resistance particularly in chloride-containing environments. However, its precipitation behavior is not well-understood and has


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therefore been exploring. Finally, an observation on a cast silver alloy was given. This precious alloy is used in jewelry in Thailand and little information on its microstructure was reported in literatures.

2. Experimental procedures Both conventional and semi-solid cast process were used to prepare the alloys. CO2-silicate and metal moulds were utilized. For semi-solid cast process, a sloped cooling plate was used whereby liquid metal was poured over a semi-circular copper plate coated with a thin layer of boron nitride to prevent sticking of solidified alloys. Specimens for examination by light microscopy (LM) and scanning electron microscopy (SEM) were prepared by a standard grinding and polishing procedure. Appropriate etchants were chosen to reveal general microstructure. An Olympus BX60M optical microscope and a JEOL 5910LV SEM, operated at 15-30 kV, were used. Thin foils for transmission electron microscopy (TEM) were prepared by a Struers Tenupol-3 twin-jet electropolisher with proper electrolytes. A JEOL JEM2010 TEM-STEM were used, operated at 200 kV.

3. Results and Discussion 3.1 High Chromium Cast Irons Microstructure and crystallography of carbides in 27-30 wt%Cr cast irons in as-cast and after destabilization and/or tempering heat treatments were revealed.[1] Eutectic and secondary carbides are mainly M7C3 and M23C6, respectively, which possess orientation relationships with their matrixes. By combining a reverse effect of some particular etchants, quantitative analyses on secondary carbide precipitation and eutectic carbide transformation due to destabilization heat treatment were successful.[2] Unusual structure, which can affect properties of casting, was firstly reported by us and the mechanism of formation has been proposed.[3] Spheroidal primary phase and radiating clusters of eutectic structure were obtained as a result of semi-solid processing.[4] Effects of some alloying elements including V, W and Mo are being investigated. 3.2 Cast Aluminium Alloy A356 A cast Al-7%Si-0.3%Mg alloy was studied in as-cast and after the T6 artificial aging heat treatment. Nanometer-scale aging precipitates were successfully revealed only by TEM.[5] The results support a suggestion on aging precipitation sequence as reported in the case of wrought Al alloys in this group; supersaturated solid solution α → GP zones I → GP zones II (β’’) → β’ → β (Mg2Si). Peak aging at 160 oC was associated with the β’’ phase. However, further experiment on HREM is needed to definitely conclude the types of the aging precipitates. 3.3 Cast Duplex Stainless Steel A cast 22wt%Cr-0.037wt%C duplex stainless steel has been studying. Slow cooling after a normal heat treatment at 1175 oC resulted in a precipitation of an intergranular precipitate.[6] This precipitation led to a detrimental effect on corrosion resistance of the alloy. An experiment on isothermal transformation between

500-1000 oC has been performed and resulted in a complex, both intergranular and intragranular, precipitation. Only SADP technique alone cannot solve firmly the structure of these precipitates and further studies using advanced techniques, e.g. CBED and EELS, is needed. 3.4 Cast Silver Alloy A 93.5wt%Ag - 6.37wt%Cu - 0.13wt%Be silver alloy was studied. Beryllium had an effect on modifying eutectic structure from a typical, pearlite-like lamellar to a structure with more sphericity and on improving the macrohardness and other mechanical properties after aging due to a fine precipitation within the primary phase, which could be revealed only by TEM. Despite a difficulty in detecting Be in this alloy by EDS, the type of aging precipitate could tentatively be Be12Ag orε -Cu.[7]

4. Conclusion Electron microscopy, especially transmission electron microscopy, is an essential technique to study precipitation and transformation in cast metals and it was succeeded for some extent. However, some difficulties still remain in (i) sample preparation and (ii) phase identification when chemical compositions are not different or light elements, e.g. B or Be, are present. FIB technique can be helpful for sample preparation and advanced techniques in TEM, e.g. CBED, HREM and EELS, are indispensable for some particular cases.

5. Acknowledgement Miss S. Imurai, Mr. N. Chomsaeng, Mr. S. Kuimalee and Mr. T. Sukree are thanked for providing their results and valuable discussion.

6. References [1] A. Wiengmoon et al., “Microstructural and crystallographical study of carbides in 30wt.%Cr cast irons”, Acta Materialia, Vol.53, 2005, pp. 4143–4154. [2] A. Wiengmoon et al., “A Microstructural Study of Destabilised 30wt%Cr-2.4wt%C High Chromium Cast Iron”, ISIJ International, Vol. 44, No. 2, 2004, p. 396. [3] A. Wiengmoon et al., “An Usual Structure of an As-cast 30%Cr Cast Iron”, ISIJ International, 45 (11), 2005, pp. 1658-1665.


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Failure of the aluminum die casting parts: Case study S. Kaewkumsai, S. Ouamparn, and A. Chianpairot

National Metal and Materials Center (MTEC), National Science and Technology Development Agency (NSTDA),

114 Thailand Science Park, Paholyothin Rd., Klong 1, Klongluang, Pathumtani 12120 THAILAND

Phone 66-2564-6500 ext.4736, Fax. 66-2564-6332, E-mail: [email protected]

ABSTRACT - The paper described failure of an aluminum die casting, as component of electricity suspensions and automotive parts, which failed within a short period after the installation and start-up. Radioscopic inspection system was used to determine the internal casting defects. It was observed that the presence of casting defects was mainly responsible for the part fracture. Fractography showed the origins coming from defects, porosity and shrinkage. The cause of failure was attributed to the presence of a high amount of defects. Based on the analysis, it is recommended that the better quality control of die casting process should be conducted in order to avoid fracture of these parts. KEY WORDS -- Aluminum die casting Porosity, Shrinkage, Fractography

1. Introduction High pressure die casting parts made of aluminum alloys offer several benefits in automotive uses. In certain, the cost efficiency of the casting process and the possibility to cast the part in thinly-wall of complex geometries led to the use of this kind of materials in new model of lightweight engines [1]. Aluminum die casting alloys are made by the rapid injection of molten metal into metal molds under high pressure. These alloys have a dense and fine grain surface, and are easily made by mass production [2]. For the applications, products with complicated structure are desired. Following increasing application for aluminum alloy die-cast products, many studies have been carried out on their mechanical properties, and it has been reported that the mechanical properties were largely influenced by casting defects, such as irregular structures, porosities, and so on. The part that applied to cyclic load was found to be fracture, especially at the thin section. Fatigue properties of aluminum components strongly depend on casting defects and microstructural appearances [3]. It has been mentioned that the tensile strength and the fatigue strength of die-casts decreased with the increase in the amount of porosities. The irregularities in the structure also affect their mechanical properties, and among irregular structures, cold flakes largely reduce the mechanical properties of the die-castings. Cold flakes are included in products during injection process of the cold chamber high-pressure die casting as follows. The solid layers are disintegrated and transmitted into the die cavity to form cold flakes in the die-castings. Shrinkage occurs during solidification as a result of volumetric differences between liquid and solid states [4]. In this present paper, failure analyses of aluminum die casting parts were conducted. The failed components were the electricity suspension and automotive parts which were made from aluminum casting. They broke after in serviced for a few periods.

2. Investigation Methods Visual examinations with the aid of a stereo microscope were thoroughly carried out on the failed parts and sites of fracture. Then, defects and discontinuities of the failed samples were observed by the radioscopic inspection system, Giladoni: CHF 225 S/G. A portion of the failed part with the fracture surface was used for fractography study using a stereo microscope and a scanning electron microscope. A spark emission spectrometer was used for determine the chemical composition of a bulk of samples. And finally, the samples were prepared using a standard metallographic technique and etched with nital (a dilute solution of HNO3 in alcohol). The microstructure of the material was analyzed by a reflected light microscope.

3. Case studies 3.1 Failure of Electricity Suspension 3.1.1 Background Information The failed components were the Strain Clamp 5U-Bolts which were made from aluminum casting grade LM6 (British Standard). They were the component of electricity system and served as a support of aluminum cable in the Scandinavia. They broke in service after a few months installed. The failed part for analysis is shown in Fig.1. 3.1.2 Radioscopic inspection Radiography of the failed parts in the fracture area reveals a large amount of internal defects and discontinuities, including shrinkage, porosity, and micro-cracks as shown in Fig.2.


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(a) (b) Fig.1 a) The failed component b) cracking site

Fig.2: X-ray (3.1 mA, 82 kV) of a failed sample at the large crack area with evidence of shrinkage porosities and crack initiated from these defects 3.1.3 Fractography The fractographs show the macroscopic features in Fig.3a. The fracture surface shows shrinkage porosities near the working surface (red arrows) and the crack directions indicates that it initiated from pores. SEM fractographs at the areas which cracks initiating are shown in Fig.3b-3c, shrinkages and porosities were found.

(a)

(b) (c)

Figure 3: SEM fractographs showing the casting defects a) macrofractography b) surface of shrinkage c) dendrite growth in shrinkage area 3.1.4 Chemical analysis Chemical composition analyses of a bulk of electricity suspension part are showed in Table 1. The results are close to the specification of LM6.

Table 1 Chemical compositions of LM6 base material

Alloy Compositions (mass %) Cu 0.09 Si 11.6 Mg 0.08 Zn 0.07 Fe 0.57 Mn 0.45 Ni 0.08 Sn 0.0.05 Al Balance

3.1.5 Microstructure analysis The microstructure of a piece of the failed sample conformed to the near eutectic structure as shown in Fig. 4a. The microstructure consisted of the eutectic silicon phase and defects with many dispersed shrinkage pores. Fig. 4b showed that the micro-crack had initiated from the shrinkage pores.

(a) (b)

Fig. 4: Microstructure of the failed part a) a large amount of porosities b) the crack linked of many pores 3.1.6 Discussions Observation from the radiography, fractography and the metallography reveals that the casting quality contributes to the fractured problem. The x-ray inspection in the fractured area shows a lot of internal defect, shrinkage porosity and micro-cracks. Microstructural analysis revealed that the cracks had initiated from the shrinkage pores. Fracture surface observations by SEM confirm that the fracture of the Strain Clamp 5U-Bolts could come from the presence of shrinkage pores and oxide film inclusions. Defects and discontinuities act as the stress concentrator and then they become the crack initiation sites for fracture under tensile and fatigue conditions. Gas pores are, typically, spherical, whereas shrinkage pores have an irregular three dimensional shape. Both of these types of pores can also be associated with aluminum oxide film [2]. Since the cold flake contains the oxide layer of poor cohesive bonding with the surrounding matrix, the cold flake reduces the mechanical properties of the die-castings components. Turbulence during melting, metal transfers and in particular during filling of the mold introduces cold flake oxide film defects that seriously reduce the mechanical properties. It is suggest that the use of non-turbulent bottom filling of moulds coupled with the use of ceramic filters in the running systems has very significant improvements in mechanical performance.


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3.1.7. Conclusion The determination of internal defect, microstructure and fractography were made that the casting defects (i.e. shrinkage porosity, oxide film inclusion) was a major contributing factor in this failure. Closely control the production line with no-turbulent flow is recommended.

3.2 Failure Analysis of an Autopart 3.2.1 Background Information The failed component was the oil-cooler part, which was the component of automotive. It was made of aluminum alloy grade ADC12 by the high pressure die casting process. Manual torque tightening was conducted for installation the oil-cooler part connecting with the engine. During performance testing for 280 hours, the oil leaked from this part. The pressure test was about 15 bars under the vibration load. As-received sample is shown in Fig. 5.

Fig. 5: The as-received automotive part for analysis 3.2.2 Visual examination Visual examination of the fractured part revealed that the part impart into two pieces produced by cracking. It generated during performance testing process. Machine cutting for opened crack was also observed in the opposite side. The fracture surface clearly exhibits the origin and the pattern. The fracture site is marked by pencil point. 3.2.3 Fracture surface analysis Fracture surface analysis with Stereo Microscope The macroscopically visible fractographic features can be used to identify the fracture origin at the external surface as shown in Fig. 6a. It can identify the fracture directions of crack propagation by redial marks. Radial marks [5] are lined on the fracture surface that radiate outward from the origin. They are formed by the propagation of brittle fractures. It does not show the beach mark patterns, characteristic of fatigue fracture. Some areas show the porosity and shrinkage porosity.

(a) (b) Fig. 6: Fractographs show a) origin (arrow) and b) porosity on fracture surface

Fracture surface analysis with SEM The fracture surface analysis with SEM shows microscopic feature as present in Fig. 6b. It shows the physical appearances of shrinkage porosity that was generated during solidification, consistent with the high pressure die casting process. 3.2.4 Chemical analysis Chemical composition analyses of a bulk of oil-cooling part are showed in Table 2. The results are close to the specification of ADC12. Table 2 Chemical compositions of ADC12 base material

Alloy Compositions (mass %) Cu 2.34 Si 11.80 Mg 0.17 Zn 0.55 Fe 0.79 Mn 0.16 Ni 0.04 Sn 0.02 Pb 0.06 Al Balance

3.2.5 Cross-section and microstructure analysis The cross-section and microstructure of the area close to the fractured surface that was observed with optical microscope are shown in Fig. 7. The microstructure shows dispersion of porosities in matrix structure (Fig. 7a). Some area is free from porosity as shown in Fig.7b. SEM micrograph shows the shrinkage porosity as shown in Fig.8. 3.2.6 Discussions The macroscopic examination of the fractured sample reveals that fracture proceeds from the external surface. This surface area exhibited the radial mark pattern, characteristic of overload and fast fracture. It probably caused due to the over-torque tightening during installation. The microstructure analysis reveals that the area near fracture surface contains some of porosity. The tensile strength and fatigue strength of die-cast decrease with the increase in the amount of porosity. The microstructure appearances were also influence to the strength of material. The porosity near the internal hole surface did not generate the crack origin. The crack was caused by bending stress. The applied and vibration loads increased the stress much more than the porosity. Then the fracture of this part could come from the overload during testing and/or the improper design, high stress concentration site, low strength of the material.

100 μm


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(a) (b)

Fig.7: Microstructure of the failed part a) showing porosities at the fracture origin area b) normal structure

Fig. 8: SEM micrograph shows the shrinkage porosity 3.2.7 Conclusion The fracture was originated at the external surface and propagated with radial mark patterns, characteristic of overload failure. The over-torque tightening could be the cause of failure. The casting defects were also acted as the contribution factor. Then, the torque tightening could closely control to prevent the overload failure. Alternatively, quality control of casting process was proposed for avoiding casting defects. 4. References [1]. Dirk Mohr, Roland Treitler, 2008, “Onset of fracture in high pressure die casting aluminum alloys”, Engineering Fracture Mechanics, Vol. 75, pp. 97–116. [2] K. Nakata, Y.G. Kim, H. Fujii, T. Tsumura, T. Komazaki., 2006, “Improvement of mechanical properties of aluminum die casting alloy by multi-pass friction stir processing”, Materials Science and Engineering A, Vol. 437, pp. 274–280. [3] Q.G. Wang et al., 2001, “Fatigue Behavior of A356-T6 aluminum cast alloys. Part I. Effect of casting defects”, Journal of Light Metals, vol.1, pp.73-84. [4] The Influence and Control of Porosity and Inclusions in Aluminum Castings, ASM Handbook. [5] Brittle Fracture, Understanding How Component Fail, ASM

10 μm


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Grain Refinement of 7075 Al-Alloy by Thermomechanical Treatment

K. Runruksa, P. Srichandr* Division of Materials Technology, School of Energy , Environment and Materials King

Mongkut’s University of Technology Thonburi (KMUTT)Thailand , Tel. 0-2470-8643, Fax 0-2427-9062, Email; [email protected]

ABSTRACT - Alloy with fine grains exhibit superior properties compare with coarser-grained ones including better strength, more toughness and better formability. Attempts are therefore made to obtain as small grains as possible in the manufacturing of metallic parts. This research attempts to refine the grain size of 7075 aluminum alloys by thermomechanical treatment process. The results showed that aging temperature influenced the final grain size considerably. With the aging temperatures of 100, 200 and 400 ºC, the resulting with final grain size were, 61, 47 and 34 microns, respectively. It is concluded that the higher the aging temperature, the smaller the final grain size. Aging time was also found to have some effect on the final grain size, though not quite in the same manner as aging temperature. It is concluded that grain refinement of 7075 alloy from 140 microns to 10 microns is attainable by thermomechanical treatment. The presence of MgZn2 in the structure prior to rolling and recrystallization anneal is required in order to obtain such fine grains. KEY WORDS -- Thermomechanical Treament, Grain Refinement, Alloy 7075

บทคัดยอ โลหะที่มีขนาดเกรนเล็กจะมีสมบัติท่ีดีกวาโลหะที่มีขนาดเกรนใหญหลายดาน เปนตนวา มีความแข็งแรงสูงกวา มีความเหนียวดีกวา การขึ้นรูปทําไดงายกวา ในการผลิตชิ้นงานโลหะจึงมีความพยายามลดขนาดเกรนโดยวิธีการตางๆ ท่ีจะทําใหโลหะมีขนาดเกรนเล็กท่ีสุดเทาที่จะเปนไปได งานวิจัยนี้เปนความพยายามที่จะลดขนาดเกรนของอลูมิเนียมผสมเบอร 7075 โดยกระบวนการเทอรโมเมคแคนนิคัล ผลการวิจัยพบวาอุณหภูมิในการบมมีผลตอขนาดเกรนคอนขางมาก กลาวคือท่ีอุณหภูมิการบม 100, 200, และ 400 oC จะไดขนาดเกรน 61, 47, และ 34 ไมครอน ตามลําดับ สรุปไดวาในชวงอุณหภูมิการบม 100-400 oC อุณหภูมิการบมสูงขึ้นจะไดขนาดเกรนเล็กลง สวนเวลาในการบมมีอิทธิพลตอขนาดเกรนเชนเดียวกันแตไมเหมือนอุณหภูมิ การปลอยใหชิ้นงานเย็นตัวอยางชา ๆ ในเตาอบหลังการบมกอนที่จะนําไปรีดและอบเพื่อใหเกิดผลึกใหมจะทําใหไดขนาดเกรนของอลูมิเนียม 7075 ท่ีมีขนาดเล็กมากระดับ 10 ไมครอน ผลการวิจัยสรุปไดวาเราสามารถปรับลดขนาดเกรนอลูมิเนียม 7075 จาก 140 ไมครอนเปน 10 ไมครอน ไดโดยกระบวนการเทอรโมเมคแคนนิคัล แตตองอบใหได MgZn2 ในโครงสรางกอนที่จะนํามารีดและอบเพื่อใหเกิดผลึกใหม คําสําคัญ -- กระบวนการเทอรโมเมคแคนนิคัล, การปรับขนาดเกรน, อลูมิเนียม 7075

1. Introduction To enhance equiaxed fine grain structure of metal and alloy; the foundry men has tried many grain refining process to treat of metal and alloy. Master alloy usually added to melt metal before pouring to achieve the 100-300� grain size area, also cold deforming and recrystallisation process are seldom used to achieve the metal structure of 40-50� grain size area. The more fine grain structure of metal the more tensile strength and more ductile metal will be. Z.M. El Narade and et al.[1,2] have founded that when grain size area of Al-alloy was reduced from 46� to 16�, more tensile strength up to 84.3% was yielded. Improve strength and ductility were improved up to 116% and 287% respectively. D.H. Shin and A. Smolej [3,10,11] found that when the grain size area of 7075 Al-alloy was reduced to 10� beside the more strength was achieved, the 7055 Al-alloy became a

superplastic behavior metal. R. Kaibyshey and et al. [4] simulated high temperature elongation of 11� grain size of 7075 Al-alloy, they founded that, due to the superplastic behavior of metal, 960% of elongated grains were achieved. Superplastic behavior of metal could fulfill the more complex shape of sheet metal could be formed such as fuselage skin or hue elongation were needed. With the problem in grain size limited effect of 70xx Al-alloy in cold deforming processes. Cold deforming process were usually performed at <0.5Tm; tearing of metal parts were usually occurred when high volume deformed metal were proceeded if large grains size after recrystallization annealed was occurred. The problem could be cured by the precipitation of small size of secondary phase during aging. F.J. Humphreys et al [7-9] had proved that when the size of secondary phase were about 1-2�they would be the nucleation site of


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smaller than 10� grains area. This paper deal with aging variables the affected the secondary phase size such as grain size after cold reduction and after recrystallization annealing. 2. Experimental procedures The 12×30×100 mm. specimen size of 7075 Al-alloy with 6Zn, 2Mg, 1.7Cu, 0.18Cr and 0.19Fe were investigated. The 140�original grains size was prepared by 1 mm. cold reduction and recrystalliation for 1 hr. at 500oC. Then the aging variables has been investigated. 2.1 The Temperature. The specimens were solution heat treated for 4 hr. at 500oC, water quenched to stabilized the solid solution at room temperature. All specimens were aged at 100, 200, and 350oC, water quenched after 12 hr. aged. After that aged specimen were rolled reduction to 2 mm at 250oC and recrystalized at 480oC for 12 hr. 2.2 The Time. The specimens were solution heat treated for 4 hr. at 500oC, water quenched to stabilized the solid solution at room temperature. After solution treatment and quenching the specimens were aged at 350oC for 1, 12, and 24 hr. All specimens were rolled reduction to 2mm. hick at 250oC followed by recrystallization at 480oC for 1 hr. 2.3 The Cooling Rate. The specimens were solution heat treated for 4 hr. at 500oC, and water quenched. After that the specimens were aged at 350oC for 12 hr. follow by furnace cooled and water quenched. After that the specimens were rolled reduction to 2 mm. thick at 250oC. After rolling the metal were recrystallized at 480oC for 1 hr. 2.4 Microstructure Development and Analysis. The rolled specimens were preparing for microstructure development and XRD analysis. Keller’s reagent was used for microstructure development with optical microscope analysis and line intercept grain size area could be determined, XRD was used to determined the composition of each phases. 3. Results & Discussion 3.1 Effect of Aging Temperature on Microstructure. Original elongated grain microstructure of alloy 7075 form supplier has shown figure 1(a), after 1 mm. cold reduction and recrystallization; grains structure of specimen has been recrysed to 140� grain size as shown in figure 1(b)and has been used as datum grain size to evaluated the effects. Aster aging process at various temperature 100. 200, and 400oC, the effect of temperature had changed the grain size of the specimen to 61, 47 and 34�respectively, the smallest grain size had shown in figure 1(c). It is clearly shown that the lower aging temperature the larger grain size will be. Since the more secondary phase would be precipitated at grain boundary than in the matrix during low temperature aging. The precipitated

secondary phase size in the matrix was to small to be nucleation site to growth. So that the recrystallization would be occurred at the former grains boundary and at sub grains site as nucleation site[5]. Even through, at higher temperature aging, such as 200oC, the smaller grain size could be occurred, but it was larger than the 400oC aging. At 200oC aging; even if the precipitated secondary phases particle were large enough to be nucleation site but the number of nucleation site were less and smaller than the 400oC aging. Then the 400oC aging was the best aging temperature to produce the fineness grains size in 7075 alloy.

(a) As-receive

(b) Grain size starting (140 micron)

(c) Aging at 400 ºC 12 hr( 34 micron)

(d) Aging at 400 ºC, 12hr,furnace cooled (10 micron)


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Figure1. Microstructure of 7075 aluminum alloys (a) as-received (b) Aging at 100 ºC (c)Aging at 200 ºC and (d) Aging at 400 ºC 3.2 Effect of Aging Time on Microstructure. At 1, 12, and 24 hr. aging time; the precipitated grains size were 65, 34, and 41� respectively, the smallest grain size was 34� as shown in figure 1(c). It was shown that since 1 hr. aging the grain size were larger as 65� than 12 and 24 hr. aging. Since the primary precipitation would be take place at the vacancies sites[5] and take time to growth or transform to another phase. So that 1 hr. aging could not enough to proceed the growth or transformation to be the nucleation site of new grains. Then the larger grain size would be form at 1 hr. aging than 12 and 24 hr. aging. The smaller grain size would be gain during 12 hr. than 24 hr. aging, since the longer aging period at the constant temperature the result of the larger precipitated phase would be. So that at higher temperature aging than solubility limit of the matrix the precipitated phase or � phase would be re-dissolve. So that longer aging time would be made the re-dissolve in the matrix more than to be growth. So 12 hr. aging would be gain the best effect of finer grain size. 3.3 Effect of Cooling Rate After Aging on Microstructure. Grain size of cold reduction and recrystallization of furnace and water quench cooled the aged specimens, grains size area of the metal specimens were 10 and 34� respectively; the smallest grain size were shown in figure 1(d). The main factors that affect the smaller grain size were 1) the more nucleation site the smaller grain size would be, 2) inhabitation of growth process of grain during cooling. Intermetallic compound in 7075 alloy such AlCr and metallic Zn were the primary solid particles that would be precipitated during recrystalliztion after final rolling. These particles of size more than 0.5�[1] would be the nucleation site for growth to be grains. Forming of these particles were the result of diffusion and growth of each alloying elements. Time and temperature would the factors that promoted the diffusion process. So that the furnace cooled specimen after recrystallization would gain the finer grain size than the water cooled specimen. Since, the furnace cooled, all the particle size would be lager and more dispersing than the water cooled specimens; cold deforming effect broke down and pushing these particles and made it more dispersing. So that after recrystalliation process the more finer grain size would be. Comparison examination Due to the XRD examination; the structure of as received 7075 alloy did not appeared the MgZn2 as shown in figure 2(a). It shown the small peak of MgZn2 in the furnace cooled 12 and 24hr. aged specimens as shown in figure 2(b)-2(c) respectively.

(a)as-receive

(b )Aging at 400 ºC ,12 h r

(b )Aging at 400 ºC ,12 hr

(c )Aging at 400 ºC ,24 hr

(d)Aging at 400 ºC 12 hr , furnace cooled Figure2. X-ray diffraction (a) as-received (b) Aging at 12hr (c)Aging at 24 hr and (d) Aging at 400 ºC ,furnace cooled


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4. Conclusions The more finer recrystaled grain size of 7075 alloy would be gained in the furnace cooled aged specimens. The fineness grain size of 10� was obtained from the cold deformed and recrystallization of 34� gain size specimen. MgZn2 were precipitated in furnace cooled aged specimens, and result in finer grain size. This research ha been reduced the gain size down to only 10�, since there were some uncontrolled factors the affecting the recrystaled process. 5. Acknowledgement The authors would like to thank the Division of Material Technology, School of Energy, Environment and Material, King Mongkut’s University of Technology Thonburi and National Metal and Materials Technology Center (MTEC) for financial supports. 6. References [1] William F. Smith, Structure and Properties of Engineering Alloys, McGraw-Hill, New York, 1993. [2] Z. M. El-Baradie, M. El-Sayed, Effect of double thermomecchanical treatment on properties of 7075 Al alloy (1995), Mat. Proc. Tech., pp. 6276-80. [3] D.H.Shin, C.S.Lee, W.J.Kim, High-temperature deformation in a superplastic 7475 Al alloy with a relatively large grain size ,(1997), Acta Mat. 45, [4.] R.Kaibyshev, T.Sakai,F.Musin, I.nikulin, and H.Miura(2001), Superplastic behavior of a 7075 aluminum alloy, Scrita mat. 45,1373-1380 [5.] Robert E.Reed-Hill, Physical Metallurgy Principles, Litton Education Publishing inc(1973).190-374. [6.] R.D.Doherty, D.A.Hughes, F.J.Humphreys, J.J.Jonus, D.Juul Jensen, Mat.Science and Eng.A238(1997) 219-274. [7.] F.J.Humphreys,(1977), The nucleation of recrystallization at second phase particles in deformed aluminium, Acta Mett.25, 1323-1344 [8.] J.Pilling and N.ridley, superplasticity in crystalline solids ,the institute of metals (1989) 17-21.65-101 [9.] F.J.Humphreys,Philip B.prangnell, Ronald Priestner, Fine-grained alloy by thermomecchanical processing, (2001),Cur.Op.Mat.Sci.5, 15-21 [10.] A.Smolej ,M.Gnamus, E.Slacek, The influence of the thermomechnical processing and forming parameters on superplastic behavior of the 7475 aluminium alloy, (2001) ,Mat.Proc, Tech. 118,397-402 [11.] D.H.Shin, K-T.Park, E.J.Lavernia (1995), High-temperature deformation in a superplastic 7475 Al alloy with a relatively lare grain size, Mat. Science. A201 ,118-126


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On the relationship between specimen thickness and graphite morphology of compacted graphite cast iron (CGI) T. Kumma, K. Teeratatpong, A. Sritong, N. Liamdee, and T. Udomphol

Suranaree University of Technology, Thailand Tel.044-224483, Fax.044-224482, E-mail:[email protected]

ABSTRACT – Graphite morphology of compacted graphite cast iron has been observed to be significantly affected by specimen thickness (1/8-2 inches) at 1500-1550oC treatment temperatures using 0.3-0.7% commercial COMPACTMAG (nodularizer). Fine graphite morphology was obtained in small thickness whereas thick sections provided coarser graphite structure. Higher treatment temperature resulted in higher losses in the amount of Mg. % Residual Mg has been observed to greatly influence the graphite morphology at individual treatment temperatures and specimen thickness investigated. KEY WORDS -- Compacted graphite cast iron, graphite morphology, specimen thickness, treatment temperature, residual magnesium บทคัดยอ ในการศึกษาการหลอเหล็กหลอกราไฟตตัวหนอนโดยทําการเติมสาร COMPATMAG (Nodularizer) ในชวง 0.3-

0.7% ท่ีอุณหภูมิ 1500-1550oC พบวา รูปทรงของกราไฟตมีความสัมพันธกับความหนาของชิ้นงานหลอ โดยมีขนาดความหนาที่ศึกษาคือ 1/8-2 นิ้ว ชิ้นงานที่บางจะใหรูปทรงของกราไฟตท่ีมีขนาดละเอียด สวนชิ้นงานที่หนาจะใหกราไฟตท่ีมีขนาดหยาบขึ้น นอกจากนี้ จะเกิดการสูญเสียแมกนีเซียมมากขึ้นหากทําการทรีทเมนตท่ีอุณหภูมิสูง และปริมาณการเติม COMPACTMAG มีความสําคัญอยางมากตอรูปทรงของกราไฟตท่ีอุณหภูมิเติมสารและความหนาตางๆกนั

คําสําคัญ -- เหล็กหลอกราไฟตตัวหนอน รูปทรงกราไฟต ความหนาชิ้นงาน อุณหภูมิทรีทเมนต แมกนีเซียมเหลือคาง

1. Introduction Compacted graphite cast iron (CGI) has been increasingly satisfied many engineering applications especially replacing some of the existing cast iron components such as diesel engines for automotive industry due to its high strength and thermal conductivity [1]. However the production of the CGI has long been difficult to achieve the desirable compacted graphite morphology, which depends significantly on magnesium treatment prior to casting as well as casting thickness. Under-treatment provides undesirable graphite flake whereas over-treatment yields nodular graphite morphology. In order to obtain the satisfied compacted graphite morphology, an investigation into the effects of specimen thickness on the graphite morphology has been carried out at 1500-1550oC treatment temperatures using 0.3-0.7% COMPACTMAG (nodularizer) to provide a useful operating window for the production of compacted graphite cast iron. 2. Experimental procedures CGI of 3.4-3.9%C, 1.8-2.1%Si compositions were melted in a 40 kg crucible followed by magnesium treatment at 1500-1550oC by adding the commercial COMPACTMAG of 0.3-0.7%. The sandwich process was carried out in a 35 kg ladle with the treatment temperatures being controlled within ±15oC prior to casting. Step bars of different thickness (1/8-2 inches) as shown in fig. 1 were cast in sand molds such that directional solidification was attained. Investigation of the graphite morphology at individual test conditions

was carried out using an optical microscope. Chemical composition of CGI castings was analyzed using a spark emission spectro analyzer whereas the carbon equivalence was measured using a carbon equivalent meter following the magnesium treatment.

Figure 1. Step bar used for CGI sand casting

3. Results & Discussion Chemical compositions and carbon equivalence (CE) of the CGI castings in different conditions are shown in table 1. The contents of carbon and silicon are in the controlled ranges, giving the CE values of 3.9-4.5. The contents of residual Mg are varied in relation to the addition of COMPACTMAG and the treatment temperatures. Mg losses occurred in greater amounts when treated at higher temperature as shown in fig. 2.

300 mm 12 inches

3.2 mm1/8 inch

6.3 mm1/4 inch

12.7 mm 1/2 inch

25.4 mm 1 inch

38.1 mm1 1/2 inches

50.8 mm2 inches

Test Area 100 mm4 inches


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Table 1. Chemical compositions of CGI castings

TTreatment oC/ %COMPACTMA

G C Si Mg % CE

1500 oC 0.3% 0.5% 0.7%

3.39 3.10 3.39

2.44 2.58 2.95

0.015 0.016 0.025

4.1 3.9 4.4

1550 oC 0.3% 0.5%

0.7%

3.38 3.39 3.40

2.63 2.78 2.85

0.009 0.014 0.016

4.5 4.3 4.1

Relationship between %COMPACTMAG and % residual Mg at different treatment temperatures

0.015 0.016

0.025

0.009

0.0140.016

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.3 0.5 0.7

%COMPACTMAG

%Re

sidu

al M

g

1500 oC1550 oC

Figure 2. Relationship between %COMPACTMAG and %residual Mg in CGI castings at 1500 and 1550oC Fig.3 shows variations of graphite morphology obtained from CGI castings in relation to % residual Mg for each specimen thickness. It can be seen that at individual specimen thickness, the graphite morphology has changed from flake to compacted (vermicular) and finally to nodular with increasing % residual Mg. This is due to the effect of Mg in promoting nodular graphite formation. At 1500oC, under-treatment giving the undesirable flake graphite was obtained especially in thick sections when treated with 0.3% COMPACTMAG whereas over-treatment has shown in small sections treated with 0.5 and 0.7% COMPACTMAG. Over-treatment appeared in a lesser extent when treated at 1550oC, due to a higher loss of Mg. According to experimental data, the desirable compacted graphite morphology has been achieved where % residual Mg lied within 0.014-0.02%. Furthermore, comparison at individual % residual Mg showed that specimen thickness significantly affected the graphite morphology. Coarsening of flake, compacted and nodular graphite has been observed for 0.009%, 0.014% and 0.025% residual Mg respectively. Potential processing window for CGI treated at 1550oC is schematically shown in fig. 4.

Figure 3. Variation of graphite morphology according to % residual magnesium at specimen thicknesses of 1/8, 1/2 and 1 1/2 inches

Figure 4.Processing window of CGI. Note: F-flake, C-compacted, N-nodular

4. Conclusions 1. An increase in specimen thickness (1/8-2 inches) has coarsened the graphite observed at each treatment temperature. 2. Increasing amounts of % residual Mg (0.009-0.025%) has changed the graphite morphology from flake to compacted and finally to nodular graphite. 5. Acknowledgement Many thanks are due to undergrads, technicians and academic supports from Suranaree University of Tech. 6. References [1] W.L.Guesser, et al, “Compacted graphite cast iton for diesel engine cylinder blocks”, 106th AFS Casting Congress, Kansas City, 4-7 May 2002. [2] X.J. Sun, et al, Identification and evaluation of modification level for compacted graphite cast iron, Journal of materials processing, 2007.

F

F

F

FF

FC

CC

C

C

C

C

C

C

N C

N

N C

NC

0.3% 0.5% 0.7% COMPACTMAG

Step 11/8 ” Step 21/4 ” Step 31/2 ” Step 41 ” Step 51 1/2 ” Step 62 ”

Treatment temperature at 1550oC

F

F F

F F

F

N

C

CC

C

C

C

C

C

C

N C

N N

C N

C

C

C N

N

NC

N

NC

C

Step 1 1/8 ” Step 2 1/4 ” Step 3 1/2 ” Step 4 1 ” Step 5 1 1/2 ” Step 6 2 ”

0.009 0.014 0.016 0.025%Mg

0.009% residual Mg 0.014% residual Mg 0.025% residual Mg

200 μm 200 μm 200 μm

200 μm 200 μm 200 μm

200 μm 200 μm 200 μm

Step 11/8 inch

Step 51 1/2 inches

Step 31/2 inch


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Size and Distribution of Primary Silicon in Semi-Solid State of A390 Aluminum Alloy Subject to Mechanical Vibration

P. Senthongkaew 1 , N. Poolthong 2 and C. Limmaneevichitr *3 1 Division of Materials Technology, School of Energy, Environment and Material,

King Mongkut’s University of Technology Thonburi, Bangkok, Thailand 2 Division of Materials Technology, School of Energy, Environment and Materials,

King Mongkut’s University of Technology Thonburi, Bangkok, Thailand 3 Department of Production Engineering, Faculty of Engineering, King Mongkut’s University

of Technology Thonburi, Bangkok, Thailand Tel. 02-470-9188 Fax. 02-470-9198 * E-mail: [email protected]

ABSTRACT - This research studied the effects of mechanical vibration in semi-solid state on size and distribution of primary silicon in A390 aluminum alloy. The molten aluminum alloy was mechanically vibrated in a stainless steel mold with six different amplitudes ranging from 17.65 to 151.38 µm and constant frequency of 200 Hz. The melt was held in molten salt bath at various temperatures to obtain the fraction of solid at 3.9, 5.0 or 7.8%. Vibration durations were set at 5 min. It was found that samples with fraction of solid at 7.8% and amplitudes of 19.73 µm had primary silicon particles about 30 µm in diameter and the tips of the primary silicon phase became smooth. It was believed that mechanical vibration caused fragmentations of primary silicon and smoothed out the morphology. The main microstructures were eutectic structures surrounded by aluminum dendrite. However, samples from vibration with amplitude of 151.38 µm increased the primary silicon size. This might result from agglomerations of primary silicon. Key Words -- Mechanical Vibration, Semi-solid, Primary Silicon, Aluminum-Silicon alloy บทคัดยอ งานวิจัยนี้เปนการศึกษาอิทธิพลของผลของการสั่นสะเทือนทางกลในสภาวะกึ่งของแข็งตอขนาดและการกระจายตัวของโครงสรางซิลิคอนปฐมภูมิของอะลูมิเนียมผสมเกรด A390 โดยทําการทดลองสั่นสะเทือนอะลูมิเนียม-ซิลิคอนผสมเกรด A390 ในเบาสเตนเลสที่คงอุณหภูมิคงที่ในอางเกลือหลอมเหลวที่ต้ังอุณหภูมิท่ีเทียบไดกับสภาวะกึ่งของแข็งที่สัดสวนของแข็งรอยละ 3.9, 5.0 และ 7.8 มีการปรับแอมพลิจูดที่คาตางๆ ท้ังหมด 6 คา ในชวงตั้งแต 17.65 ถึง 151.38 ไมครอน โดยใชเวลา 5 นาทีท่ีคาความถี่ 200 Hz จากการทดลองพบวาสัดสวนของแข็งรอยละ 7.8 สั่นที่แอมพลิจูด 19.73 ไมครอน ทําใหซิลิคอนปฐมภูมิมีรูปทรงสัณฐานปลายมนและมีขนาดเสนผานศูนยกลางเฉลี่ยประมาณ 30 ไมครอน ในปริมาณมากที่สุด ท้ังนี้คาดวาการสั่นสะเทือนทางกลที่เหมาะสมทําใหผลึกซิลิคอนปฐมภูมิเกิดการแตกหักและปลายมน กระจายตัวอยูในโครงสรางพื้นฐาน โดยโครงสรางสวนใหญเปนยูเทคติคและปรากฏเดนไดรทอะลูมิเนียมรอบๆผลึกของซิลิคอนปฐมภูมิ อยางไรก็ตามเมื่อเพิ่มคาแอมพลิจูดเปน 151.38 ไมครอน พบวาซิลิคอนปฐมภูมิโดยสวนมากมีขนาดใหญขึ้นและปลายมน ซึ่งอาจเกิดจากผลึกซิลิคอนปฐมภูมิเกิดรวมตัวเปนกลุมกอนขนาดใหญขึ้น คําสําคัญ -- การสั่นสะเทือนทางกล, ก่ึงของแข็ง, ซิลิคอนปฐมภูมิ, อะลูมิเนียมผสมซิลิคอน

1. Introduction Aluminum-Silicon alloy grade A390 has been continuously used with much attention in automobile industries. The major application is for making piston due to several specific properties such as high strength, excellent in wear resistance and low thermal expansion coefficient. In general, fine primary silicon is preferable to obtain better properties for general applications [1-6]. The conventional method to obtain fine primary silicon is to add phosphorus. However, the technique was not completely controllable and subject to cause detrimental effect when contaminated with modifier. Lu et al. [4] obtained fine primary Si particles by electromagnetic force. However, using

electromagnetic force is rather expensive. Some investigators used mechanical vibration technique to refine primary silicon because it is much cheaper as compared to using electromagnetic force [6-8]. However, the vibration acted on aluminum melt in a short period of time during solidification. In this research, mechanical vibration in z-direction was used during semi-solid state of aluminum melt for 5 minutes so the vibration may better act on the silicon refinement.


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2. Experimental procedures An A390 Al-Si ingot of 170 grams was melted using an induction furnace using silicon carbide as crucible. After complete melting at 700°C, the melt was poured into a stainless steel mold (50- mm. in diameter and 90-mm. in height.) that was set inside a salt bath as illustrated in Fig. 1. The salt bath was set at temperature to obtain the solid fraction of 7.8, 5.0 or 3.9 %. The molten aluminum alloy was mechanically vibrated and isothermally held in a stainless steel mold with six different amplitudes of 17.65, 19.73, 45.86, 90.41 and 151.38 µm and constant frequency of 200 Hz for 5 minutes. Finally, the stainless mold was quenched into water bath and the sample was then prepared for light optical microscope examination and particle size and distribution of primary silicon analysis mainly on zone B.

Figure 1. Schematic sketch of mechanical vibration equipment set in salt bath. Figure 2. Zones for microstructure analysis. 3. Results and Discussion The melt was isothermally held at various temperature representing different solid fractions of 3.9, 5.0 and 7.8 %. It was found that the average primary silicon sizes are 63, 85 and 105 µm, respectively. Isothermal holding the melt at high solid fraction resulted in larger primary silicon size. As shown in Fig. 3, the morphology of primary silicon is mainly polyhedral with aluminum dendrite around.

(a) (b) (c) Figure 3. Micrographs showing samples holding at various fractions of solid (a) 3.9% (b) 5.0 % (c) 7.8 % with no vibration. It should be noted that the temperatures for different fractions of solid were calculated based on chemical composition using Thermo-calc. The other set of experiment was conducted in similar way by isothermal holding the melt at different fractions of solid. However, the mechanical vibration was introduced into the melt during holding the melt at different temperature to obtain different fractions of solid as shown Fig 4. It was found that, at certain amplitude range, average primary silicon size decreases with increasing amplitude at the fraction of solid of 5.0 and 7.8%. If the amplitude was higher than about 40 micron, the size became larger again. It is interesting to see that increasing amplitude did not reduce the size of primary silicon for samples with large fraction of solid, i.e. 7.8%. The graph showing primary silicon size subject to mechanical vibration at different amplitudes and fraction of solid was demonstrated in Fig. 5. To better understand the size distribution of primary silicon, the size distributions were determined. However, the complete size distribution cannot be presented here because of space limitation.

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Figure 4. Microstructure showing the effect of mechanical vibration to amplitude: (a) 0 µm (b) 19.73 µm (c) 151.38 µm

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Because appropriate primary silicon size for general application is 21 – 35 µm, the size distribution in this range was also plotted against amplitude at various fractions of solid as shown in Fig. 6. It was found that samples with vibration in the amplitude range of 20 to 40 µm at fractions of solid of both 5.0 and 7.8% have highest primary silicon content in this range. However, the primary silicon in the range of 21- 35 µm in the samples from fraction of solid of 3.9% is very low as compared to that of samples from higher fraction of solid. Figure 5. Effect of amplitude on the average primary Si size at various fractions of solid. Figure 6. Size distribution in the range of 21-35 µm against amplitude at various fractions of solid. Abu-Dheir et al. [6] indicated that applying mechanical vibration to the mold during solidification has a strong effect on both microstructure and mechanical properties of castings. However, the mechanism responsible for such effects is not well understood. They also reported that when vibration amplitude exceeds a critical value that tends, the primary silicon will become coarsen. In addition, primary silicon dispersed in eutectic structure and has polyhedral primary silicon form; however, aluminum dendrite is still periphery to primary silicon. Mechanical vibration technique may act on primary silicon particles in semi-solid state resulting in different in size and distribution of resultant primary silicon phases in the similar way previously reported by Lu et al. [4] that when the fraction of solid is high enough.

4. Conclusion (1) Mechanical vibration in z-direction together with

isothermally holding in various temperatures for different fractions of solid results in different sizes and distributions of primary Si.

(2) The critical vibration amplitude was found and caused the primary silicon phases become coarsen.

(3) The mechanism responsible for mechanical vibration effects is not well understood.

5. Acknowledgement The authors would like to thank Mr. Monchai Laliturai, Lenso Wheel, co., ltd. for Thermo-Calc calculation support. Faculty of Engineering at Kasetsart university is sincerely appreciated for financial support for one of the authors (Mr. Payoon Senthongkaew). 6. References [1] Gruzleski, J.E. and Bernard, C.M., 1990, The treatment of Liquid Aluminium Silicon Alloy, American Foundrymen’s Society,AFS ,Inc.Illinois, pp.1-94. [2] Nogita, K., et al., 2004, “Aluminium phosphide as a eutectic grain nucleus in hypoeutectic Al-Si alloys” Electron Microscopy 53., Vol. 4, pp. 361-369. [3] Kapranos, P., Kirkwood, D.H. and Atkinson, H.V., 2003, “Thixoforming of an automotive part in A390 hypereutectic Al–Si alloy”, Materials Processing Technology, Vol. 135, pp. 271-277. [4] Lu, D., et al., 2007, “Refinement of primary Si in hypereutectic Al-Si alloy by electromagnetic stirring”, Materials Processing Technology, Vol.189, pp. 13-18. [5] Shu-suo, L., Ai-min, Z., Wei-nin, M. and Xue-you, Z., 2000, “Mechanical properties of hypereutectic Al-Si alloy by semisolid processing”, Transactions of nonferrous metals society of china., Vol.10, No.4, pp. 441-444.

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Powder Metallurgy of Silver Nanoparticles for Jewelry Making

P. Thongnopkun,1 W. Sroisuriya,2 and S. Ekgasit2

1Faculty of Gems (Chanthaburi), Burapha University, Chanthaburi 22170, THAILAND

Tel. (+66) – 8 – 1996 – 0902; E – mail: [email protected] 2Sensor Research Unit, Department of Chemistry, Faculty of Science,

Chulalongkorn University, Bangkok 10330, THAILAND Tel./Fax. (+66) – 2218 – 7585; E – mail: [email protected]

ABSTRACT – Silver nanoparticles were successfully synthesized using chemical reduction

method in aqueous solution. The particles were precipitated and dried in order to make nano-

silver powder. SEM images show their size in the range of 50 – 200 nm. Silver nanoparticles

powder was mixed with organic binder and water to be nano-silver clay. The clay can be shaped

like any soft clay, by hand or using moulds. Sintering temperature of the synthesized nano-silver

clay is 300 ºC which is lower than that of commercial silver clay. The synthesized nano-silver clay

becomes silver metal after firing at 600 ºC for 30 min. It can be applied for jewelry and art

works.

KEY WORDS – Silver nanoparticles, Silver clay, Sintering temperature, Jewelry making

บทคัดยอ อนุภาคขนาดนาโนของเงินถูกสังเคราะหขึ้นดวยวิธีเคมี และตกตะกอนใหอยูในรูปของแข็งลักษณะเปนผง

การศึกษาดวยกลองจุลทรรศนอิเล็คตรอนแบบสองกราดพบวาขนาดอนุภาคเงินที่สังเคราะหไดอยูในชวง 50 – 200 นาโนเมตร ผงอนุภาคซิลเวอรนาโนเมื่อนํามาผสมกับตัวประสานอินทรียและน้ําจะไดนาโนซิลเวอรเคลยท่ีมีลักษณะคลายดินเหนียว สามารถปนขึ้นรูปดวยมือและแมพิมพได อุณหภูมิในการเผาผนึกของผงอนุภาคซิลเวอรนาโนมีคาประมาณ 300ºC ซึ่งต่ํากวาซิลเวอรเคลยท่ีมีขายเชิงพาณิชย ผงอนุภาคซิลเวอรนาโนสามารถเผาขึ้นรูปเปนโลหะเงินไดท่ีอุณหภูมิ 600ºC เวลา 30 นาที และสามารถนําไปประยุกตทําเปนเครื่องประดับและงานศิลปะอ่ืนๆได

คําสําคัญ – อนุภาคขนาดนาโนของเงิน, ซิลเวอรเคลย, อุณหภูมิเผาผนึก, การทําเครื่องประดับ

1. Introduction The gems and jewelry industry has been a powerful export earner for Thailand. In jewelry industry, there are many techniques for making jewelry products depending on its design, value, demand, consumer, etc. The general manufactures of jewelry are manual, casting, pressing and electroforming techniques. For silver jewelry, there is a large of energy lost in melting and molding process of silver metal because the melting point of silver metal is about 960ºC. However, its melting temperature tends to decrease depending on its particle size. Silver clay is an alternative way for producing unique handmade jewelry. Silver clay is made of micron-sized silver particles, water, and non-toxic organic binders. When firing at appropriated temperature (650-850°C), the organic binders burn off, leaving a pure silver piece. In recently, the new product of metal clays tend to have small metal particles and low proportions of binder and water in

order to make them stronger, low shrinkage, and able to sinter faster at lower temperatures. When particle size is decreased to nanometer level, the melting point goes down from normal melting point more than several hundred Celsius degree. In this work, silver nanoparticles were introduced to create nano-silver clays. Their particle size and sintering temperature were determined. Example of nano-silver clay jewelry was presented. 2. Experimental procedures Silver nanoparticles were synthesized by chemical reduction method in aqueous solution with concentration 10,000 – 50,000 ppm. The particles were precipitated from silver nanoparticles colloid and were dried to be nano-silver powder at room temperature. Particle size of silver powder was characterized by scanning electron microscope (SEM) and sintering temperature of silver clay was determined by


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differential temperature analysis (DTA). The nano-silver powder was mixed with organic binder and water in appropriated ratio to form nano-silver clay. The clay was molded to be many shapes for making jewelry. After drying, the clay was sintered by oven at 600ºC for 30 min. 3. Results & Discussion Fig. 1 shows the shape and particle size of nano-silver powder. The particle size is in range of 50 – 200 nm and the shape is spherical.

Figure 1. SEM images of silver powder.

Sintering temperature of silver clay was determined by differential temperature analysis (DTA). It was found that sintering temperature is ≈ 300ºC far less than normal melting point, 960ºC. When silver clay was heated, water was evaporated and silver particles moved closer. After firing at 600ºC for 30 min., nano-silver clay changed to silver metal. It may cause that silver particles are quite small, there is a small cavity between particles and then they sintered without porosity. As shown in Fig. 2 and 3, the nano-silver clay can present the fine texture of fingerprint and can roll to make the complex jewelry.

Figure 2. Sintered silver clay of finger print.

Figure 3. Example of nano-silver clay jewelry. 4. Conclusions Nano-silver power was produced from high concentration silver nanoparticles colloid. Their particle sizes are 50 – 200 nm. The sintering temperature is at 300ºC. The powder was mixed with water and organic binder to be silver clay. The nano-silver clay can be shaped by hand or using mould to make jewelry. The firing temperature and time are 600ºC and 30 min., respectively. 5. Acknowledgements The authors gratefully acknowledge support from the Thailand Research Fund (TRF) and Commission on Higher Education (CHE). 6. References [1] Hirasawa, J. and Ido, Y., Silver Powder for Silver Clay and Silver Clay Containing This Silver Powder, US Patent No. 007081149B2, 2006. [2] Wang, H.; Qiao, X.; Chen, J. and Ding, S., Preparation of Silver Nanoparticles by Chemical Reduction Method, Coll. Surf. A, 2005, 256, 111-115

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