Study on grain size control technology of 304L austenitic stainless steel

Abstract

In order to solve the problem of mischcrystal in 304L stainless steel with thickness of over 40mm, a series of critical process parameter were studied in laboratory and trial product, such as rolling cycle, temperature of recrystallization controlled rolling, holding time and cooling mode after rolling. The results show that the deformation at 1050°C and 950°C has no significant effect on the recrystallization ratio. The steel plate was dephosphorized by descaling box after the steel was taken out of the heating furnace. After three passes of longitudinal rolling, the steel plate was turned to cross rolling. Before the cross rolling, the surface of the middle slab was dephosphorized, while the remaining passes were not dephosphorized. Static recrystallization could be completed after a short time of warming. The effects of temperature and time on grain growth were compared under the same deformation conditions, it is found that temperature is a sensitive factor for grain growth. The higher the temperature is, the process of recrystallization and grain growth almost happens at the same time. The lower the temperature, the higher the proportion of recrystallization can be maintained, and the abnormal grain growth can be inhibited, which can effectively improve the problem of mischcrystal.