| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nonoriented silicon steel sheet minimal in iron loss by specifying respective contents of C, Si, Mn, P, sol.Al, and S. SOLUTION: The steel sheet has a composition consisting of, by weight, <=0.005% C, 1.5-3.5% Si, 0.05-1.0% Mn, <=0.2% P, <=0.004% sol.Al, <=0.001% S, and the balance Fe with inevitable impurities. If respective contents of S and sol.Al are within the prescribed range, the ordinary manufacturing method of nonoriented silicon steel sheet can be adopted. Molten steel, blown in a converter, is subjected to degassing treatment for adjustment to a prescribed composition and successively cast and hot rolled. There is no necessity for specifying finishing temp. and coiling temp. at the time of hot rolling, in particular. Hot rolled plate annealing after hot rolling can be done but is not essential. Subsequently, the resultant steel plate is cold rolled once or is cold rolled two or more times while process annealed between cold rolling stages to prescribed sheet thickness, followed by final annealing. The resultant steel sheet can be widely used as an electric material requiring low iron loss, such as transformer and motor. |
