| 摘要 |
PURPOSE:To obtain a grain-oriented silicon steel sheet having an excellent iron loss characteristic by controlling the relation between the final thickness of the cold-rolled silicon steel sheet having a specific compsn. and the oxygen coating weight of the surface oxide layer formed by decarburization annealing of the steel sheet within a specific range. CONSTITUTION:A silicon steel stock contg. <=0.06wt% C, 2.0-4.0% Si, 0.01- 0.20% Mn and 0.008-0.100%>=1 kind of S and Se is hot-rolled. The hot-rolled steel sheet is then cold-rolled to <=0.25mm. final product thickness. After the steel sheet is subjected to decarburization annealing, a separating agent for annealing consisting principally of MgO is coated on the surface of the steel sheet and the steel sheet is subjected to finish annealing. The annealing temp. and annealing atmosphere are so controlled that the oxygen coating weight Os(g/m<2>) in the surface oxide layer formed by the decarburization annealing satisfies the condition of the inequality; 4t+ 1.6>=Os>=-8t+3.1 according to the thickness (t). The grain-oriented silicon steel sheet having an excellent iron loss characteristic is stably produced by the above-mentioned method. |
