Microstructure and Magnetic Properties of Fe-4.5% Si Thin-Gauge Non-Oriented Electrical Steel

In this study, Fe-4.5% Si thin-gauge non-oriented electrical steel with a thickness of 0.20 mm and 0.15 mm were prepared by an innovative and convenient twin-roll strip casting process. The evolution of microstructure and texture of the cast strip under different rolling deformation with/without annealing treatment was studied. The microstructure and texture of the material were characterized by optical microscope, electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results indicate that the shear band of the annealed cast strip was not obvious after rolling deformation, while a common cold rolling texture (γ-fiber texture) was formed. The as-cast strip with/without annealing treatment showed {411} <148 > texture after warm rolling and final annealing. The latter formed a stronger {411} <148 > texture and directional nucleation was the main mechanism for the formation of recrystallized texture. Regarding the magnetic properties, the annealing treatment of the cast strip did not improve the magnetic induction of the thin-gauge strip but increased the core loss. The 0.20 mm thin-gauge non-oriented electrical steel prepared by the cast strip without annealing treatment exhibited the best magnetic properties with B₅₀ = 1.674T, P_15/50=2.10 W/kg, P_10/400=12.28 W/kg, P_10/1K=12.56 W/kg. Although the magnetic induction of 0.15 mm thin-gauge non-oriented electrical steel reduced relatively, a lower core loss was obtained.