| 摘要 |
PURPOSE: To more stably produce a high Mn type grain oriented silicon steel sheet improved in magnetic properties to a greater extent. CONSTITUTION: A steel plate, which has a composition consisting of <=0.01% C, 1.5-4.0% Si, 1.0-5.0% Mn, <=0.01% S, 0.003-0.03% sol.Al, 0.0010-0.010% N, and the balance Fe with inevitable impurities and satisfying Si(%)-0.5×Mn(%)<=2.0 and in which the part in the range from each surface to the position at a depth 10-70% of the whole plate thickness from each surface is formed into recrystallized part, is used, and this steel plate is cold-rolled once or cold-rolled twice while process-annealed between the cold rolling stages, heated rapidly and annealed, and then subjected to secondary recrystallization and purification annealing at 825-1050 deg.C, or, a steel having the composition is used and this steel is hot-rolled while regulating the relation between finishing temp. (FT) and coiling temp. (CT) so that they satisfy 1250-(2/3)×FT<=CT<=1300-(2/3)×FT and 780<=FT<=930 or CT<=600 and annealed at 625-950 deg.C, and the part in the range from the surface to the position at a depth 10-70% of the plate thickness is formed into recrystallized part before cold rolling. |
