Study on microstructure evolution and properties of Fe-3.1% Si steel for new energy vehicles by adjusting normalizing temperature

Abstract Non-oriented silicon steel, a kind of Fe-Si alloy with high magnetic induction, high strength (mainly referring to yield strength), and low iron loss, is needed for the motor rotor of new energy vehicles. In this study, Fe-3.1% Si steel, which was 0.27 mm thick, was manufactured at different normalizing temperatures. The microstructure and the texture evolution of each process were studied. As the normalizing temperature rises, fine equiaxed recrystallized grains of normalized sheets are coarsened while the area fraction of elongated grains drops off. The mean size of recrystallized grains and the microstructure uniformity of final annealed sheets both increase with normalizing temperature from 800°C to 980°C. The magnetic and mechanical properties are well balanced in the case of 900°C normalization. The annealed sheet exhibits excellent properties with core loss P 10/400 of 16.65 W/Kg, magnetic induction B 50 of 1.70T, and yield strength YS of 446 MPa.