| 摘要 |
PURPOSE:To obtain a grain-oriented silicon steel sheet having a high magnetic flux density and low iron loss by heating quickly a bland material of a silicon steel which has a prescribed compsn. and is made to a final thickness at a specific average rate and annealing the steel respectively in oxidation atmospheres under two partial pressure ratios of PH2O/PH2 in the stage of subjecting said blank material to decarburization and primary recrystallization annealing. CONSTITUTION:A blank material of a silicon steel contg., by wt%, 0.01-0.06% C, 2.0-4.0% Si, 0.01-0.25% Mn and 0.005-0.1% S or/and Se is subjected, after hot rolling, to 1 pass of 2 passes of cold rolling including intermediate annealing to a final thickness. The silicon steel sheet having the final thickness is quickly heated from 400 deg.C up to 750 deg.C at >=10 deg.C/sec average heating rate and thereafter the sheet is annealed in an oxidation atmosphere of 0.4-0.7 PH2O/PH2 (partial pressure ratio) in a temp. range of 780-820 deg.C. In succession, the sheet is annealed in an oxidation atmosphere of 0.08-0.4 PH2O/PH2 in a temp. range of 830-870 deg.C. The steel is further subjected of final finish annealing to develop the secondary recrystal grains in the (110) [001] bearing by which the objective grain-oriented silicon steel sheet is obtd.
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