Heterogeneous lamellar structure simultaneously enhances strength, toughness and magnetic properties of high-silicon ferritic steel plates

High-silicon ferritic steel plates fabricated by hot rolling and normalizing exhibited polygonal ferrite grains with weak texture, which poses challenges for simultaneously improving strength, impact toughness and magnetic properties. Herein, a heterogeneous lamellar structure consisting of elongated deformed grains and polygonal recrystallized grains, and strong λ-fiber texture was achieved via warm rolling and tempering. High-density dislocations enhanced strength. Promoting delamination and suppressing deformation twinning improved impact toughness. Despite the unfavorable high-density dislocations, strong λ-fiber texture significantly improved magnetic properties. This work provides a highly potential approach for overcoming trade-offs among strength, impact toughness, and magnetic properties of ferritic soft-magnetic steel.