| 摘要 |
PURPOSE:To obtain a silicon steel sheet useful for small-size transformer by performing the finish annealing of a rolled silicon steel sheet by means of continuous annealing in which tension in a longitudinal direction of rolling and temp. are respectively specified to reduce the iron loss value of a steel sheet in a longitudinal direction. CONSTITUTION:A hot rolled plate for nonoriented silicon steel sheet, having a composition consisting of, by weight, <=0.01% C, 2.5-5.0% Si, 0.1-1.5% Mn, <=2.0% Al, and the balance Fe with inevitable impurities, is cold-rolled once or cold-rolled while process-annealed between the cold rolled stages and worked to the final sheet thickness. Subsequent finish annealing is done by means of continuous annealing under the conditions of >=0.3kgf/mm<2> tension in the longitudinal direction of rolling of the steel sheet and of 980-1100 deg.C temp. By this procedure, the iron loss ratio between the iron loss W15/50(L) in the longitudinal direction of rolling of the steel sheet and the iron loss W15/50(C) in a crossing direction is regulated so that C/L>=1.25 is satisfied. By this method, the iron loss value in the L direction can be reduced by increasing tension at the time of annealing, and the silicon steel sheet capable of being advantageously utilized for a small-size transformer as specific purpose can be obtained. |
