The effect of grain size before cold rolling on the magnetic properties of thin-gauge non-oriented electrical steel

Abstract

Thin-gauge non-oriented electrical steel was processed by one-stage cold rolling using different normalizing time, and the through-process texture evolution was studied. Strong {411}〈148〉 recrystallization textures were obtained in sheets subjected to longer normalization time. After cold rolling reduction, the initial {411}〈148〉 texture transformed to {114}〈110〉 and {311}〈136〉 textures. As the rolling reduction increased, the {311}〈136〉 texture transformed into a {112}〈110〉 texture, but not a {111}〈112〉 texture. In normalized sheets with large grains, more shear bands formed during cold rolling, which provided more nucleation sites for {100}〈013〉 oriented grains. The nucleation sites of {100}〈013〉 grains existed at {112}〈110〉 and {100}〈011〉 deformed grain boundaries and in the {112}〈110〉 and {111}〈112〉 orientation shear bands. Strong {100}〈013〉 textures formed due to the high mobility and large grain size. As the normalizing time increased, the magnetic properties were greatly improved in the final annealed sheets. The superior magnetic induction was due to the strong {100}〈013〉 and {210}〈001〉 textures and the weak {111}〈112〉 texture. A larger grain size and weaker γ texture reduced the hysteresis loss, which caused low core losses in the final annealed sheets.