| 摘要 |
PURPOSE:To obtain a fine and uniform structure and to provide uniform and superior magnetic properties free from linear fine grains by applying hot rolling to a silicon-containing steel slab after raising the temp. in a position at a specific depth from a surface layer by means of induction heating under specific conditions. CONSTITUTION:Prior to the hot rolling of a silicon-containing steel, a slab is subjected to induction heating at 1380-1470 deg.C average temp. under the conditions satisfying relationships in an inequality. By the above heating, a temp. in a position at a depth of 1/10 from a surface layer is regulated so that it is higher by 15-50 deg.C than the temps. in the central part and the outermost surface layer. In the successive hot roughing stage, a crystalline structure is controlled in a thickness direction and grain growth in the abnormal grain growth of equiaxed crystals in the center of thickness is inhibited. By this method, a grain-oriented silicon steel sheet having a grain size distribution uniform in a sheet-thickness direction and also having superior magnetic properties can be obtained. |
