Effect of Low-temperature Annealing on Mechanical Properties of Warm-rolled High Silicon Steel Produced by Twin-roll Strip Casting

The 1.7-mm-thick as-cast 6.5 wt.%Si steel strip was prepared by a top side-pouring twin-roll caster. The strip is subsequently warm-rolled to 0.4 mm at 700 degrees C. The warm-rolled sheets were cold-rolled to 0.15 mm after being annealed at various temperatures between 250 and 450 degrees C for 1 hour. The microstructure, microhardness, and room temperature mechanical properties, residual stress, dislocation density, ordered phases of the warm-rolled sheet and the annealed sheets were studied and analyzed. Due to the combined effect of residual stress, dislocation density, and ordered phases, the microhardness of the annealed sheets and the edge cracks of cold-rolled sheets showed a trend to decrease first and then increase with the increasing of annealing temperature. The room temperature plasticity showed a trend to increase first and then decrease. When annealing is done at 350 degrees C, the plasticity of the warm-rolled sheet at room temperature can be improved.