Optimizing texture and enhancing magnetic properties in ultra-thin non-oriented electrical steel via a two-stage rolling process

Abstract

Ultra-thinning of non-oriented electrical steel enhances the energy conversion efficiency and power density of drive motors used in new-energy vehicles. In this study, ultra-thin Fe-4.5 wt% Si sheets (0.15 mm) were successfully fabricated using both a one-stage heavy rolling and a two-stage rolling methods. Electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) were used to characterize the microstructure and texture of the sheets. The distinct deformation textures in the one-stage heavy-rolled and two-stage rolled sheets resulted in recrystallized grains that formed primarily in deformation bands and shear bands, respectively. Furthermore, quasi-in situ EBSD characterization revealed that the one-stage rolled sheet developed strong γ-fiber ({111} ) and {411} textures, whereas the two-stage rolled sheet formed pronounced η-fiber ({hk0} ) during recrystallization. After complete recrystallization, the two-stage rolled sheet showed a significant increase in η-fiber content (from 3.2 % to 28.6 %) and a decrease in γ-fiber content (from 49.5 % to 22.3 %) compared with the one-stage rolled sheet. Through texture optimization, the two-stage rolled ultra-thin sheet achieved superior magnetic properties with a magnetic induction (B50) of 1.64 T and an iron loss (P1.0/400) of 7.95 W/kg. This study establishes a comprehensive methodology for texture optimization and magnetic property enhancement in high-grade ultrathin non-oriented silicon steel, providing critical insights for the development of advanced electrical steel.

Keywords

• Non-oriented electrical steel
• EBSD
• Texture evolution
• Recrystallization
• Magnetic properties