Evolution of Texture, Microstructure and Magnetic Properties in Fe-0.7%Si Non-oriented Silicon Steel Processed by Twin-roll Strip Casting

A non-oriented Fe-0.7% Si steel as-cast strip was produced by an industrial twin-roll strip casting production line. The evolution of the microstructure, texture, and properties was characterized along the entire processing route. The microstructure of each cross-section of the industrial cast strip was found to be uniform, with low texture strength and random orientation distribution. After cold rolling, a mixed microstructure formed, consisting of deformation structures and shear bands alternating in the thickness direction. The texture exhibited a mixed texture combining α-fiber texture (<110>//RD) and γ-fiber texture (<111>//ND). During the 850°C annealing process, recrystallized grains nucleated preferentially in shear bands, and α texture and Goss texture began to form. The final annealed sheet texture was composed of Goss texture and γ-fiber texture, with favorable textures constituting the major part. The final sheets exhibited excellent magnetic properties: P1.5/50 = 4.915 W/kg, B50 = 1.856T in RD direction, and P1.5/50 = 5.347 W/kg, B50 = 1.765 T in TD direction. Its average yield strength was approximately 278.77 MPa, and the average tensile strength was approximately 505.47 MPa. After aging at 300°C for 10 hours, only a few precipitates formed in the final sheets, and their magnetic properties remained highly stable with little to no change.