Numerical simulation of dynamic strain-induced austenite–ferrite transformation in a low carbon steel

A modified cellular automaton modeling has been performed to investigate the dynamic strain-induced transformation (DSIT) from austenite (γ) to ferrite (α) in a low carbon steel. In this modeling, the γ–α transformation, ferrite dynamic recrystallization and the hot deformation were simulated simultaneously. The simulation provides an insight into the mechanism of the ferrite refinement during the DSIT. It is found that the refinement of ferrite grains derived from DSIT was the result of the increasing ferrite nuclei density by the “unsaturated” nucleation, the limited ferrite growth and the ferrite dynamic recrystallization. The effects of prior austenite grain size and strain rate on the microstructural evolution of the DSIT ferrite and the characteristics of the resultant microstructure are also discussed.