Effect of cold rolling process on texture evolution of gradient microstructure in Fe-3,0 % Si non-oriented silicon steel

This study focused on the microstructure evolution of non-oriented Fe-3,0 %Si steel used in the core of new energy vehicle drive motor. An hot band and a sample normalized at 800 °C for 10 min were subjected to a moderate cold rolling and an annealing treatment. The results show that the initial hot band has gradient microstructure. After normalizing, the surface is consisted of fine recrystallized grains, the central layer has elongated α-fiber and γ-fiber grains, the subsurface shows a mixed grain structure with strong Goss texture. After cold rolling with a thickness reduction of 40 %, α-fiber and γ-fiber textures are strengthened, and unstable Goss texture disappears. After annealing at 700 °C for 5 min, gradient recrystallization occurs and γ-fiber texture is weakened. The central and subsurface layers show frequently nucleation phenomena in the grain interior and grain boundaries, resulting in strong Ѳ-fiber, α*-fiber and Goss components.