Investigation of the Two-Step Hot Rolling Process of High-Grade Non-oriented Electrical Steel

The 0.35 mm-thick high-grade non-oriented electrical steel sheets were produced by different two-step hot and cold rolling processes. The microstructure and texture evolution of different paths in the whole process were compared. The gamma-fibre texture was remarkably weakened by reducing the second hot-rolled reduction and increasing cold-rolled reduction. In particular, the sample from route B (the second hot-rolled reduction was 66.7% and cold-rolled reduction was 82.5%) had a large amount of in-grain shear bands in these samples, while the densely fibrous microstructure was not formed. The in-grain shear bands replaced deformation bands and provided nucleation sites for lambda-fibre grains. And the sample exhibited stronger {001} and {001} components compared with samples from other routes after final annealing. The suitable cold-rolled microstructure with a large amount of in-grain shear bands was responsible for the annealing texture.