Effect of initial grain size on microstructure, texture and magnetic properties of non-oriented electrical steel

The effect of initial grain size prior to cold rolling on the microstructure, texture evolution, and magnetic properties of Fe-3.5 wt% Si non-oriented electrical steel (NOES) was investigated through the introduction of normalization. There were massive intragranular shear bands in {111}<110> and {111}<112> deformed grains in the cold-rolled sheet with large initial grain size, providing nucleation sites for new recrystallized grains with Goss ({110}<001>), λ-fiber, γ-fiber, and {113}<631> components. Subsequent annealing resulted in weaker γ-fiber ({111}<110>−{111}<112>), stronger α*-fiber concentrated at {113}<631>, along with Goss and λ-fiber ({100}<001>−{100}<012>) textures. In addition, appropriate final annealing temperature effectively reduced iron loss. The simultaneous optimization of texture and grain size by normalization and annealing treatments led to improved magnetic properties, with the superior magnetic induction (B50 = 1.719) T, and the lowest core loss (P15/50 = 2.69 W/kg, P10/400 = 16.337 W/kg).