1998 Fiscal Year Final Research Report Summary
Analysis and Formulation of Evolution of Hot Deformation Microstructure in Ultra-Low Carbon Steels
| Project/Area Number |
08455342
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Shizuoka Institute of Science and Technology |
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Principal Investigator |
YADA Hiroshi Shizouka Institute of Science and Technology, Faculty of Science and Technology, Professor, 理工学部, 教授 (90239781)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGATA Hiroshi Yamaha Motor Co. LTD., R & D Division, Chief Engineer, 技術本部・基盤技術研究, 主任技師
李 春明 静岡理工科大学, 総合技術研究所, 特別研究員
TANAKA Koji Shizouka Institute of Science and Technology, Faculty of Science and Technology, Research Associate, 理工学部, 助手 (50288403)
LI Chun-ming Shizouka Institute of Science and Technology, Center for Advanced Technology, Visiting Professor
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| Project Period (FY) |
1996 – 1998
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| Keywords | Low Carbon Steels / Ni Steels / Mn Steels / Hot Deformation / Deformation Stress / Transformation / Grain Refinement / High Tensile Steels |
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| Research Abstract |
A computer model which predicts microstructural changes during hot deformation of steels has been already developed, but it has not been able to be applied to low carbon steels containing carbon no more than 0.05 mass%. Recently, such low carbon steels MC being produced more and more in quantity, so the extension of the above model to them has become a very urgent problem.
Hot deformation of three Fe-Ni-C and four Fe-Mn-C alloys whose carbon content range between 0.0008 and 0.495 mass% were studied in torsion. An in-situ X-ray diffraction study during hot torsion proved that γ→α transformation occurred during deformation around their thermodynamical γ→α transformation start temperatures. Although deformation stress decreased corresponding to the transformation, it was shown that it scarcely changed according to the carbon content when the transformation did not occur.
These results indicate that the above computer program can be used even in low carbon steels whose carbon contents are no more than 0.05 mass%. The temperature range of the above transformation was roughly determined and the cause of the transformation was discussed. It was pointed out that much more work is needed to formulate the kine6cs of the transformation.
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