| 摘要 |
PROBLEM TO BE SOLVED: To produce a grain oriented silicon steel sheet with high magnetic flux density, having superior glass film, by specifying S content in a stock of specific composition, forming a specific oxide film by decarburizing annealing, and also specifying a separation agent at annealing at the time of finish annealing. SOLUTION: A slab, having a composition consisting of, by weight, 0.025-0.10% C, 2.5-4.5% Si, 0.05-0.45% Mn, 0.01-0.06% acid-soluble Al, 0.0005-0.013% N, 0.01-0.50% Sn, and the balance Fe with inevitable impurities, is used as a stock. Further, the content of S in the stock is regulated to 0.012-0.023%. The stock is heated to <=1250 deg.C and hot-rolled. The resultant hot rolled plate is cold-rolled at >=50% final cold rolling draft. The resultant cold rolled sheet is subjected to decarburizing annealing to form an oxide film in which (FeO+MnO)/SiO2 is regulated to 0.1-0.50 and also the amount of SiO2 is regulated to (0.6 to 1.7)g/m<2> . Finish annealing is performed after a separation agent at annealing is applied to the steel sheet. This separation agent at annealing is prepared by adding 0.01-0.10 pts.wt. of chlorine compound (expressed in terms of chlorine) and/or 0.05-2 pts.wt. of the compounds of Sb, B, Sr, and Ba to 100 pts.wt. of MgO. |
