| Project/Area Number |
02555140
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属加工(含鋳造)
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| Research Institution | the University of Tokyo |
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Principal Investigator |
SUZUKI Toshio the University of Tokyo, Faculty of Engineering, associate professor, 工学部(試), 助教授 (70115111)
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| Co-Investigator(Kenkyū-buntansha) |
MIZUKAMI Hideo the University of Tokyo, Faculty of Engineering, research associate, 工学部(試), 助手 (30229687)
IKEDA Minoru the University of Tokyo, Faculty of Engineering, research associate, 工学部, 助手 (50167243)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1992: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1991: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1990: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Stainless Steel / Strop Casting / Raped Solidification / Optical Temperature Measurement / 準安定相 / 冷却速度 |
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| Research Abstract |
A new system using a photo-diode was developed for measuring the surface temperature of a rapidly solidifing sample. With the system the precise thermal history during the initial stage of solidification of 18Cr-8Ni stainless steel was measured. From the obtained cooling curves. it was shown there existed large undercooling before nucleation. Cellular structure of metastable austenitic phase was formed near the surface of the sample. Effects of atmosphere gas. materials and roughness of chill plates. temperature of chill plate on the solidification behavior and the formed structure were systematically investigated. The obtained results are summarized as follows; 1) the degree of undercooling depends only on cooling rate, 2) Surface structure changes from meta-stable austenitic cell to stable feritic dendrite with the decrease of cooling rate and 3) the transitional cooling rate from meta-stable phase to stable one is about 5000 degree per second. One dimensional solidification analysis shows that there exist large temperature gradient and growth velocity near the surface. which relate the formation of cool structures. Explanation for the cell formation using dendrite growth theory has been also tried, but simple growth model without nucleation mechanism is not enough to describe the phenomena obtained in the experiments.
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