| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a grain-oriented silicon steel sheet having high space factor by adding the specified amount of boric acid compounds into annealing separation agent in the case of manufacturing the grain-oriented silicon steel sheet having no finishing annealing film from a hot rolled silicon steel sheet. SOLUTION: The final thickness of the hot rolled silicon steel sheet is obtained by applying once or twice or more cold rollings interposing intermediate annealing with or without annealing for the hot rolled sheet. Next, decarburizing annealing is applied to the cold rolled steel sheet, thereafter annealing separation agent mainly containing non-hydrated oxide (alumina) is coated with or without nitriding, coiling is performed, finishing annealing is applied, whereby the grain-oriented silicon steel sheet having no finishing annealing film is manufactured. By wt. 0.2-1.5% boric acid compounds (ortho-boric acid, etc.) are added into annealing separation agent in this manufacturing process. By this way, the grain-oriented silicon steel sheet having high space factor and excellent characteristic is obtained. |
