Patent ID: 6436199
Filing Date: 2002-08-20
Classification: C21D,H01F

Abstract:
A method for manufacturing a non-oriented magnetic steel sheet having a low iron loss and a high magnetic flux density, comprising the steps of:preparing a molten steel containing from about 1.5 to about 8.0 weight % silicon, from about 0.005 to about 1.50 weight % manganese, and not more than about 50 ppm of each of sulfur, nitrogen, oxygen, and boron; forming a slab from the molten steel; hot rolling the slab; annealing the hot-rolled steel sheet; cold rolling, comprising cold rolling the annealed steel sheet once or cold rolling the annealed steel sheet at least twice with an interim annealing step therebetween, so as to achieve a final thickness; and annealing the cold-rolled steel sheet for recrystallization; wherein the carbon content is controlled to be about 50 ppm or less during preparation of molten steel or prior to the step of annealing the cold-rolled sheet for recrystallization, and wherein the step of annealing the hot-rolled sheet is performed in a temperature range from about 800 to about 1,200Â° C. and a temperature is subsequently decreased from about 800 to about 400Â° C. at a rate of from about 5 to about 80Â° C./second.