| 摘要 |
PROBLEM TO BE SOLVED: To stably improve the magnetic properties and coating characteristics by regulating the thickness of a silica-enriched layer contg. lamellar SiO2 in an oxidizing layer formed by primary recrystallization annealing, the content of S in the whole body of a separation agent for annealing and their product respectively to specified ranges. SOLUTION: A steel stock contg., by weight, 2 to 4.5% Si is subjected to hot rolling and cold rolling to regulate its sheet thickness into a final one, which is thereafter subjected to primary recrystallization annealing. At this time, the atmosphere, temp. and time are controlled, and the thickness (w) (μm) of the lamellar SiO2 layer in an internal oxidizing layer is regulated to 0.2 to 3.6. After the annealing, a separation agent for annealing essentially consisting of MgO is used. At this time, the value (s) (%) expressed with the content of S in the whole body of a separation agent for annealing including an addition agent and MgO impurities as SO3 is regulated to 0.1 to 2.8. Moreover, the product of the (w) and (s) is allowed to satisfy the rage of 0.15<=w.s<=3.3. After the application of the separation agent for annealing, finish annealing is executed. |
