Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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Research Abstract |
Under heating method by electric resistance of sample itself such as high-frequency induction, a steel is heated efficiently.It is,therefore,reasonable to expect that the transformation occurs under noneqilibrium state by considerable rapid heating. The present work was carried out,aiming to obtain fundamental information relevant to process of nonequilibrium reversion with rapid heating. The effect of alloying elements and prior structure have been investigated. One alloy (A) contains 0.2% carbon and the other alloy (B) contains low alloy such as molybdenum and nickel. The prior structure was selected as a thermal, cold rolled, and recrystallized martensite. The results are as follows: (1) On heating no carbide precipitation was detected in non-deformed structure,whereas the formation of fine carbide was detected in deformed structure. (2) Martensite is directly reversed to austenite without occurrence of martensite recrystallization,i.e. formation of ferrite, in non-deformed structure. But formation of recrystallized martensite was detected in deformed structure. (3) The critical deformation to detect carbide precipitation and recrystallized martensite on heating is about 10%. (4) Precipitated carbide is finer in alloy (B steel) as comparison with that in free alloy(A steel). (5) There is excellent relative relation between the grain size of recrystallized martensite and that of reversed austenite.Decreasing the grain size of recrystallized martensite,does that of reversed austenite decreases. It suggests that grain boundary of recrystallized martensite is one of important nucleation site of austenite.
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