High-permeability and thin-gauge non-oriented electrical steel through twin-roll strip casting

Highlights: • 0.2-mm-thick non-oriented electrical steels with high-permeability were successfully fabricated by strip casting. • As-cast {100} texture can be partially retained even though for a deformation with reduction up to 91%. • New Goss and Cube substructures were formed in the deformed {110}〈110〉 grains. • Annealed sheets processed by one-stage rolling exhibited strong {111}〈112〉, {223}〈110〉 and weak Goss and Cube textures. • High magnetic induction B₅₀ of 1.72 T with strong Cube and Goss texture was obtained by two-stage rolling. Texture optimization has always been a challenge to fabricate non-oriented electrical steels (NOES). In the present study, thin-gauge NOES with high permeability was successfully processed using an innovative and convenient twin-roll strip casting process without hot rolling. The relation between the as-cast microstructure, processing route and texture evolution was studied. The results indicated that as-cast strip with coarse grains exhibited strong {100}〈0vw〉 texture and unique {110}〈110〉 component. Annealed sheets processed by one-stage rolling displayed pronounced {111}〈112〉, {223}〈110〉 components and weak Cube and Goss texture. Micro-texture characteristics revealed that {100}〈0vw〉 texture was partially retained from initial grains, and new Cube and Goss substructures were generated within {110}〈110〉 deformed grains during cold rolling. This was responsible for the development of Cube and Goss recrystallization texture. Furthermore, the application of two-stage rolling not only reinforced these two behavior, but also accelerated the nucleation of η grains because of the increased shear bands in cold-rolled sheets. In this manner, an improved texture consisting of dominant η-fiber, weak γ-fiber and optimized magnetic properties (B₅₀ = 1.72 T, P_10/400 = 14.91 W/kg) were obtained.