Patent ID: 9240265
Filing Date: 2016-01-19
CPC Classification: C21D,C22C,C30B,H01F

Claim Text:
1. A method for manufacturing a grain-oriented electrical steel sheet having excellent magnetic properties, the method comprising: heating a slab comprising 2.0-4.5 wt % of Si, 0.001-0.10 wt % of C, 0.010 wt % or less of Al, 0.08 wt % or less of Mn, 0.005 wt % or less of N, 0.005-0.050 wt % of S, and the balance of Fe and unavoidable impurities; hot-rolling the heated slab; subjecting the hot-rolled steel sheet to one cold rolling or two or more cold rollings with intermediate annealing therebetween; subjecting the cold-rolled steel sheet to decarburization and recrystallization annealing; and subjecting the annealed steel sheet to secondary recrystallization annealing, wherein, the secondary recrystallization annealing is performed by heating the decarburized and recrystallized steel sheet to a temperature of at least 1,000° C. to cause secondary recrystallization of the steel sheet, subjecting the secondarily recrystallized steel sheet to homogenization heat treatment at a temperature of 1,000° C. or higher for within 1 hour (excluding 0 hour), and cooling the homogenization heat-treated steel sheet, and when subjecting the annealed steel sheet to secondary recrystallization annealing, the secondary recrystallization is caused when at least one of elementary S, which segregates to grain boundaries, and FeS precipitates inhibit grain growth.