Microstructure, texture and magnetic properties of Fe-4.5 wt% Si electrical steel fabricated by double-pass rolling method

Abstract In this study, the high-performance Fe-4.5 wt% Si electrical steel thin strips were fabricated by double-rolling process combined with recrystallization annealing. Particular emphasis was placed on the effect of cold rolling reduction rate and annealing heating rate on microstructure and texture evolution of Fe-4.5 wt% Si electrical steel. The results demonstrated that with the increasing of cold rolling reduction, the deformation texture gradually evolved from {111} to {111}, accompanied by a progressive increase in the number of {100} nucleation within the {111}-oriented matrix shear bands. Under slow heating annealing, the steel demonstrated a prominent nucleation advantage for {100}-oriented grains. Consequently, a λ-fiber (//ND) recrystallization texture with strong {100} component formed after recrystallization annealing. In contrast, rapid heating annealing promoted the abnormal growth of η-fiber (//RD) oriented grains via high-energy grain boundary migration, resulting in a η-fiber recrystallization texture dominated by the {110} component. Compared with rapid heating annealing, slow heating annealing yielded sharper favorable textures and more homogeneous recrystallized microstructures, thereby endowing the steel with superior magnetic properties. Under this process, the 0.15 mm sheets exhibited optimal magnetic properties, with B 50 of 1.704 T, P 1.0/50 of 1.12 W/kg, P 1.0/400 of 14.7 W/kg, and P 1.0/1000 of 58.2 W/kg.