Abstract: In order to solve the problem of mischcrystal in 304L stainless steel with thickness of over 40 mm, the key parameters of rolling through laboratory experiments were studied, including rolling temperature in recrystallization zone and non-recrystallization zone, rolling time and cooling rate after rolling. The results show that the deformation at 1050 ℃ and 950 ℃ has no significant effect on the recrystallization ratio. Static recrystallization can be completed after a short time of warming. The effects of temperature and time on grain growth are 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. The results of industrial application show that, the abnormal grain size is accompanied by relatively high starting rolling temperature. If the rolling temperature is controlled below 1050 ℃, the grain size can be refined whether by directly rolling or by temperature-controlled rolling.

Key words: 304L stainless steel, medium-thickness stainless steel plate, mischcrystal, controlled rolling