Effects of Cr Content on Microstructure, Texture, and Properties of 0.3 mm 3.3 wt% Si Nonoriented Electrical Steels

This study examines the effects of the addition of nonferromagnetic Cr on the microstructure, texture, magnetic, and mechanical properties of 0.3 mm‐thick 3.3 Si +0.7Al (wt%) nonoriented electrical steel. It is found that, on one hand, the addition of Cr promotes the precipitation of M 7 C 3 carbides and inhibits recovery and recrystallization, thus resulting in the reduction of grain sizes in hot‐rolled, normalized, and annealed sheets. The smaller grains prior to cold rolling finally enhance the detrimental γ ‐fiber (<111>//ND) recrystallization texture. On the other hand, the addition of Cr significantly increases the electrical resistivity of steels. Therefore, as the Cr content increases, the magnetic induction B 50 significantly decreases while the iron loss P 15/50 increases. By contrast, the iron loss P 10/400 decreases first and then increases whereas P 10/1000 steadily decreases. These results suggest that Cr‐alloying is an effective way to reduce the iron loss at testing frequencies ≥ 400 Hz. In addition, it is found that the yield strength of the annealed sheets increases as the Cr content increases mainly by solid solution strengthening and precipitation strengthening.