| 摘要 |
PURPOSE: A method for magnetic-annealing high flux density grain-oriented electrical steel sheet is provided to minimize magnetostriction by giving a proper magnetic field correspondingly to application stress characteristics of the high flux density grain-oriented electrical steel sheet. CONSTITUTION: In a method for manufacturing high flux density grain-oriented electrical steel sheet comprising a process of hot rolling the steel slab by reheating a steel slab comprising 0.02 to 0.1 wt.% of C, 1.0 to 4.8 wt.% of Si, 0.006 wt.% or less of S, 0.01 to 0.05 wt.% of acid soluble Al, 0.05 to 0.2 wt.% of Mn, 0.010 wt.% or less of N, 0.001 to 0.012 wt.% of B and a balance of Fe and other inevitable impurities in the temperature range of 1,200 to 1,300 deg.C; a process of hot annealing the hot rolled steel slab in the temperature range satisfying the following expression: 1,360-11,111x£sol. Al(wt.%)|±100 deg.C; a process of cold rolling the hot annealed steel slab; a process of forming AlN by performing decarburization and nitriding annealing simultaneously or sequentially; and a process of performing tension coating on the annealed strip after final finish annealing the resulting strip, the method for magnetic annealing the high flux density grain-oriented electrical steel sheet comprises magnetic annealing step of finishing impressing of magnetic field before 200 deg.C as cooling the strip to a temperature of 720 to 350 deg.C at a cooling rate of 120 deg.C/sec or less by starting impressing a pulse magnetic field having pulse width of 10 to 40 ms and frequency of 1 to 8 Hz in a width direction of the strip in an intensity of 400 to 700 Oe; and a step of performing simultaneous decarburization-nitriding annealing by applying stress of -5 MPa to +4 MPa in the process of cooling the strip for hardening coating layer after completing tension coating.
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