Development of Very Tough Ferritic Stainless Steels by Optimizing the Recrystallized Microstructure

Abstract

In this work, the conventional rolling (CR) and warm rolling (WR) have been carried out with an ultra purified ferritic stainless steel. After different rolling processes and subsequent recrystallization annealing, different recrystallized microstructure characteristics had been obtained. It was observed that as compared to the conventional process, the warm rolling and subsequent recrystallization annealing could obviously refine the recrystallized microstructure of the hot band. The ductile-to-brittle transition for the ultra purified ferritic stainless steel can be closely related to the occurrence of deformation twinning. The refined microstructure can decrease the temperature at which twinning occurs and, consequently, the ductile-brittle transition temperature for the ultra purified ferritic stainless steel was lowered to be below -40°C, and its notch toughness was significantly improved when the fine grain route can be applied.