| 摘要 |
PURPOSE:To modify surfaces, to reduce edge crack, and to improve weldability and the adhe sive strength of an insulating film while maintaining superior magnetic properties, by providing a multilayered silicon-containing steel sheet having, as a thickness-specified surface layer of a silicon steel sheet having a specific composition, a shell layer in which alloy concentration is low as compared with that in the inner layer part. CONSTITUTION:This silicon steel sheet is constituted of a multilayered structure consisting of the surface layer part in which thickness is regulated to >=3mu per side and also to <=20%, in total of both steel-sheet surfaces, based on the whole thickness of the steel sheet and the inner layer part as the balance in the direction of sheet thickness. Moreover, the above surface layer part has a composition A consisting of, by weight, <=0.010% C, 0.05-0.5% Mn, <1.0% Si, <=0.1% P, <=0.05% S, <=0.005% N, 0.005-0.1% SolAl, and the balance Fe, while the above inner layer part has a composition B consisting of 1.0-7.0% Si, 0.005-1.0% SolAl, and the same components as those in the above composition A. In order to manufacture this steel sheet, an ingot whose shell layer and inner layer are constituted of the compositions A, B, respectively, is prepared by means of a stage of casting a shell in which thickness is regulated to >=2.5mm and also to <=20%, in total of both steel-ingot surfaces, based on the whole thickness of the steel ingot and a stage of casting the inner part of the steel ingot. This steel ingot is subjected to hot rolling, descaling, cold rolling, and then annealing. |
