Microstructure Formation of Low-Carbon Ferritic Stainless Steel during High Temperature Plastic Deformation

Abstract

In this paper, the effects of the deformation temperature, the deformation reduction and the deformation rate on the microstructural formation, ferritic and martensitic phase transformation, stress–strain behaviors and micro-hardness in low-carbon ferritic stainless steel were investigated. The increase in deformation temperature promotes the formation of the fine equiaxed dynamic strain-induced transformation ferrite and suppresses the martensitic transformation. The higher deformation temperature results in a lower starting temperature for martensitic transformation. The increase in deformation can effectively promote the transformation of DSIT ferrite, and decrease the martensitic transformation rate, which is caused by the work hardening effect on the metastable austenite. The increase in the deformation rate leads to an increase in the ferrite fraction, because a high density of dislocation remains that can provide sufficient nucleation sites for ferrite transformation. The slow deformation rate results in dynamic recovery according to the stress–strain curve.

Keywords

• ferritic stainless steel
• plastic deformation
• dynamic strain-induced transformation