| 摘要 |
PURPOSE: A method for manufacturing a low temperature reheating oriented electrical steel sheet without a glass film is provided to obtain an oriented electrical steel sheet in which punching property is improved without glass film by using a composition in which alumina powder is added to an alumina sol a main constituent of as a fusion preventing agent. CONSTITUTION: In a method for manufacturing an oriented electrical steel sheet comprising the processes of hot rolling after low temperature reheating to a temperature of 1250 to 1340 deg.C a steel slab comprising 2.9 to 3.3 wt.% of Si, 0.025 to 0.045 wt.% of C, 0.015 wt.% or less of P, 0.08 to 0.020 wt.% of sol-Al, 0.0080 to 0.012 wt.% of N, 0.007 wt.% or less of S, 0.12 to 0.42 wt.% of Mn, 0.6 wt.% or less of Cu and a balance of Fe and other inevitable impurities; annealing the hot rolled steel slab at a temperature of 1000 deg.C or less; cold rolling the annealed steel slab, thereby adjusting to a final thickness by performing two times of cold rollings including decarburization annealing under the humid environment in the middle of the cold rollings; coiling to a large scale coil by coating the recovery annealed steel slab with a fusion preventing agent after recovery annealing the cold rolled steel slab under the dry environment of 600 deg.C or less; performing finishing high temperature annealing passing through the heat cycle steps of comprising maintaining a temperature increasing ratio of 15 deg.C/hr in the range of 700 to 1200 deg.C, uniformly heating the steel slab at the temperature of 1200±10 deg.C for more than 20 hours and cooling the steel slab; and coating a tension coating agent on the resulting steel slab, wherein the fusion preventing agent comprises solid contents of 10 to 25 wt.% of alumina sol and 5 to 20 wt.% of alumina powder, and coated in an amount of 3 to 7 g/m2.
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