| 摘要 |
PURPOSE:To obtain a nonoriented silicon steel sheet having uniform magnetic properties by subjecting a silicon steel slab in which respective contents of Al, S, etc., are controlled to hot rolling and to winding at respectively specified temps., carrying out hot-rolled plate annealing under specific conditions, and then applying cold rolling and continuous annealing to the above plate. CONSTITUTION:A slab having a composition consisting of, by weight, <=0.01% C, 1.0-4.0% Si, 0.1-0.5% Mn, <0.005% S, <=0.002% Al, <=0.05% P, <=0.0030% N, and the balance Fe with inevitable impurities is cast continuously. Hot rolling is carried out from the state where the surface temp. of the cast slab does not fall below 1000 deg.C or from the state where the cast slab is soaked for >=10min after reheated from a state of <=600 deg.C up to >=1000 deg.C, and rolling is finished at 750-850 deg.C, followed by winding at <650 deg.C. Subsequently, hot-rolled plate annealing is performed under the condition of temp. T( deg.C) and time (t)(min) satisfying the conditions in an inequality I or II. Then, the rolled plate is cold- rolled once or cold-rolled twice or more while process-annealed between the cold rolling stages, followed by continuous annealing at 800-1050 deg.C. If necessary, B is incorporated to the above steel composition so that the ratio of B to N is regulated to 0.5-2.0. |
