| 摘要 |
PURPOSE:To obtain the good titled film even in coil having large simplex weight, by controlling oxygen partial pressure in atmosphere at finish annealing and electrostatically coating MgO on annealing separator material when grain oriented electrical sheet is manufactured by usual method. CONSTITUTION:Slab contg. by weight 3.0-4.5% Si, <=0.010% S + 0.405 Se, {0.05 + 7 (S + 0.45 Se)}-0.8% Mn is hot and cold rolled, and decarburization annealed in wet hydrogen atmosphere. Next, annealing separator material composed mainly of MgO is coated to the sheet and it is finish annealed to manufacture grain oriented electric sheet. Hereupon, slurry state annealing separator material of <=4g/m<2> per one side of steel sheet is coated, dried and 3-6g/m<2> MgO per one side of steel sheet is electrostatically coated thereon. Further oxygen partial pressure (PH2O/PH2) in atmosphere from finish annealing starting to 650 deg.C is controlled to <=0.015 to carry out annealing. Thereby, the cause of pepper and salt fault in forsterite film on steel sheet surface can be prevented. |
