Microstructure, Texture, and Deep Drawability Under Two Different Cold-Rolling Processes in Ferritic Stainless Steel

Abstract

In the present study, the through-thickness texture evolution and grain colony distribution in ferritic stainless steel under two different cold-rolling processes have been investigated with the aim to enhance deep drawability. It was shown that in the case of conventional cold-rolling process, at the surface, mid-thickness between the surface and the center, and center layers, all the textures consisted of very sharp α-fiber and weak γ-fiber with a peak at {111}〈110〉 after cold rolling, and non-uniform γ-fiber recrystallization textures were formed after final annealing. In case of two-step cold-rolling process, by contrast, all the textures were dominated by sharp α-fiber and weak γ-fiber after cold rolling to 50% reduction, and {111}〈112〉 became the prominent component after subsequent annealing. The α-fiber and γ-fiber with a peak at {111}〈112〉 were intensified after cold rolling to 60% reduction, resulting in the formation of uniform γ-fiber recrystallization textures after final annealing. Furthermore, after two-step cold-rolling process, the final sheet exhibited a more homogeneous distribution of grain colonies. Therefore, the deep drawability of final sheet was significantly improved after two-step cold-rolling process. It was elucidated that the selective growth mechanism was responsible for the characteristics of γ-fiber recrystallization texture under conventional cold-rolling process, whereas γ-fiber recrystallization texture development was controlled by the oriented nucleation mechanism in the two-step cold-rolling process.