Effect of final thickness on the microstructure, texture and magnetic properties of high-grade non-oriented electrical steel sheets

The high-grade non-oriented electrical steel normalized sheets from an enterprise was cold rolled with different cold rolling reduction ratios and annealed at high temperature to obtain final sheets at different thicknesses. Final thickness on microstructure, texture and magnetic properties were studied by means of EBSD. The results showed that the total iron losses continued decreasing as the thickness of final sheets decreased, especially at high frequencies, the underlying reason of which was that eddy current losses dominated at high frequencies, and at the same time its proportion to total iron losses decreased continuously as the thickness of final sheets decreased. The average grain size decreased slightly and the microstructure uniformity deteriorated with the thickness reduction of final sheets. Given that the reduction of eddy current losses caused by thickness reduction still dominated, the total iron losses decreased. With the increase of cold rolling reduction ratio, the γ texture and α^* texture were continuously enhanced while the λ texture was weakened. The volume fraction ratio of the favorable texture to the harmful texture continued declining, leading to the decrease of magnetic flux density B₅₀.