Microstructure and texture evolution of non-oriented silicon steels with different silicon contents

The microstructure and texture evolution of non-oriented silicon steels with three distinct silicon contents (1.0, 1.6, and 3.5 wt.%) were systematically investigated throughout the entire production chain, with a specific emphasis on the normalizing and annealing behaviors of the 3.5 wt.% high-silicon steel. The results demonstrate that mold electromagnetic stirring (EMS) effectively refines the continuous casting slab, achieving over 60% equiaxed grains dominated by {100} and {110} textures. In hot-rolled sheets, increasing silicon content suppresses recrystallization from the surface to the center, establishing a pronounced through-thickness texture gradient characterized by subsurface Gaussian and core α/γ textures. While normalizing preserves the {110}<001> Gaussian texture on the surface, subsequent cold rolling induces a critical texture transition: the initial Gaussian oriented grains fail to survive large deformations, and the α texture progressively transforms into the α* texture during annealing (800-1000 °C). Mechanistically, the elevated silicon content increases deformation resistance and recrystallization activation energy by hindering dislocation motion and reducing stacking fault energy, thereby creating a "slow nucleation, fast growth" kinetic regime. This unique recrystallization dynamic explains why high silicon steel exhibits larger grain sizes after normalizing despite a lower recrystallization fraction after hot rolling, ultimately leading to a reduction in detrimental {111} texture and an enhancement of favorable {110}/{100} components in the final annealed product.