Toshinari Hirayama1 and Masahiko Ogirima1
1Central Research Laboratory, Hitachi Ltd., Kokubunji
In order to investigate the influence of working temperature on the martensitic transformation which is closely related to the mechanical properties, the Fe-Cr-Ni stainless steel sheets containing 16.5 ∼ 19%Cr and 7 ∼ 11.5%Ni were rolled at several temperatures between room temperature and 200°C, and the saturation flux densities of these specimens were measured to estimate the amount of martensite. Furthermore, the relations among chemical composition, working temperature and amount of generated martensite was considered thermodynamically.
The results obtained are summarized as follows. The stainless steel, which has a chemical composition in which the austenite is unstable at nomal temperature, generates more strain-induced martensite with lowering working temperature. In this respect, the rise in working temperature by 10°C is equivalent thermodynamically to the increase in the Ni equivalent by 0.3%. This deduction coincides with experimental results.
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