Study On Microstructure And Texture During Hot Rolling And Normalizing Of Twin-roll Cast Silicon Steel Strip

The production of silicon steel by strip casting has a unique advantage, which has brought a worldwide interest in the iron and steel industry. Hot rolling and normalizing are vital front procedures in the manufacturing of silicon steel, which affect the microstructure and texture development and influence the final magnetic property. So the study on micostructures and textures during hot rolling and normalizing are important and necessary.In this study,2 mm thick silicon steel strip was produced by strip casting, afterwards hot rolled into 1 mm and then normalized at three temperatures for various time. The microstructure and texture of cast, hot rolled and normalized strips were investigated. Recrystallization of 3.67% Si steel were studied with point counting.The obtained results show that the microstructure of cast strip is heterogeneous through thickness:equiaxed grains in the surface, poor developed columnar grains from the surface to the centre layer. A through thickness gradient of texture forms in cast stript:{001} in surface layer,{115} and{110} betweeen surface layer and centre layer,{110}<110> in the centre layer.The hot rolled textures of the surface and the 1/4 layer are mainly made up of Goss component, and mainly a and y fibers in the centre layer.The hot rolled strip with reduction rate of 50% at 700℃, can not get fully recrystallized and by normalizing at 900,1000 and 1100℃.After normalizing, the silicon steel strip remains the texture component of hot rolled strips in various layers. However, Goss texture in the surface layer decreases a little with the increase of normalizing temperature or time.When 3.67Si% steel hot rolled with reduction rate of 60% at 1200℃, the recrystallization curvs is Xrex=1-exp(?)and the recrystallization activation energy is 288kJ/mol.