| 摘要 |
PURPOSE: A method for manufacturing non-oriented electrical steel sheet having low core loss after performing stress relief annealing even when hot rolled strip does not pass through annealing and skin-pass processes is provided. CONSTITUTION: The method comprises the steps of reheating a steel slab comprising 0.005 wt.% or less of C, 0.0005 to 0.005 wt.% of S, 0.0005 to 0.005 wt.% of N, 0.1 to 1.5 wt.% of Si, 0.1 to 1.0 wt.% of Al, 0.1 to 1.0 wt.% of Mn, 0.016 to 0.160 wt.% of P and a balance of Fe and other impurities in the temperature range of 1,050 to 1,250 deg.C; hot rolling the reheated steel slab to a thickness of 1.8 to 3.0 mm; coiling the hot rolled coil in the temperature range of 600 to 800 deg.C; pickling the coiled hot rolled strip; cold rolling the pickled strip to a thickness of 0.2 to 0.65 mm for one time; annealing the cold rolled strip to a temperature controlled according to P content in the temperature range of 700 to 800 deg.C, that is, Ta=400-100xlog(P/160)±5 deg.C for 30 to 300 seconds, wherein Ta is proper annealing temperature of cold rolled strip, and P is P content (wt.%); processing the annealed strip by end users; and stress relief annealing the annealed strip processed by the end users in the temperature range of 700 to 850 deg.C.
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