Effect of hot rolling temperature on the structure and magnetic properties of high permeability non-oriented silicon steel

1.3%Si steel hot bands were produced by hot rolling in a Steckel mill with two entrance temperatures: 1000 degrees C (gamma rolling) and 910 degrees C (alpha+y rolling). Hot band samples were processed with and without hot band annealing (900 degrees C for 30s), cold rolled to final thickness of 0.5mm and annealed in H-2-25%N-2 at 900 degrees C for 40s. The combination of high hot rolling temperature and hot band annealing resulted in lower core loss and higher permeability. Although no significant differences were observed on the hot band microstructures, after hot band annealing the gamma rolled sample showed a larger grain size. The final results were attributed to the effect of the initial grain size prior to cold rolling on microstructure and texture after annealing.