Abstract: Secondary cold rolling process was implemented for the trial production of high-grade non-oriented silicon steel, which had a thickness of 0.25 mm and a Si content of 3.5%. The evolution of microstructure and texture of the non-oriented silicon steel at different intermediate annealing temperatures (850, 950 and 1050 ℃) was studied by means of OM, EBSD, XRD and square coil magnetic properties testing. The results show that with the increase of intermediate annealing temperature, the average grain size of the finished annealed sheet increases first and then decreases, and the strength of the cube and Goss textures of the finished annealed sheet increases first and then decreases, the magnetic induction strength B₅₀₀₀ of the finished annealed sheet increases first and then decreases, while the iron loss value P_1.0/400 decreases first and then increases. When the intermediate annealing temperature is 950 ℃, due to the larger average grain size and the best grain uniformity, the number of shear bands after two-stage cold rolling is the highest, providing a large number of nucleation sites for cube and Goss textures during the annealing process of the finished sheet, resulting in texture strengths of 13.56 and 5.03, respectively, resulting in the highest magnetic induction intensity, with B₅₀₀₀ of 1.691 T, and the iron loss is the lowest, with P_1.0/400 of 13.36 W/kg.

Key words: non-oriented silicon steel, intermediate annealing temperature, secondary cold rolling process, texture, magnetic properties