| 摘要 |
PURPOSE:To produce a grain-oriented silicon steel sheet excellent in magnetic properties by subjecting a silicon steel slab to hot rolling and annealing, providing the surface with grooves having a specified shape, subjecting it to primary recrystallization annealing, coating it with a separation agent for annealing, subjecting it to secondary recrystallization annealing and executing heat flattening. CONSTITUTION:A silicon steel slab contg., by weight, 0.03 to 0.12% C and 2.5 to 4.5% Si is heated to >=1200 deg.C, is hot-rolled, is successively subjected to annealing and rapid cooling and is thereafter subjected to cold rolling for one time or >=two times including annealing to regulated its sheet thickness into a final one. The surface of the cold rolled steel sheet is provided with grooves in which the average of the depth on the maximum part is regulated to 2 to 50mum in the direction of 45 to 90 degrees from the rolling direction of the steel sheet at interval, by a mechanical method or the like. This cold rolled sheet is subjected to primary recrystallization annealing including decarburization, is thereafter coated with the one obtd. by mixing 0.5 to 20 pts.wt. sulfides of Li, K, Na and other elements to 100 pts.wt. MgO as a separation agent for annealing and is subjected to high temp. finish annealing also serving as secondary recrystallization annealing in an atmosphere contg. <=25% H2. The grain-oriented silicon steel sheet having no glass film and low in core loss can be produced. |
