Patent ID: 8231739

Claim:
A method for producing grain-oriented silicon steel containing copper, comprising: secondary refining and continuous casting of molten steel in a converter or an electric furnace to obtain a casting blank having the following composition based on weight: C 0.010%-0.050%, Si 2.5%-4.0%, Mn 0.1%-0.30%, acid soluble Al (Als) 0.006%-0.030%, Cu 0.4%-0.7%, N 0.006%-0.012%, S≦0.025%, balanced by Fe and unavailable inclusions; forming a hot rolled sheet by hot rolling the casting blank; acid washing the hot rolled sheet; forming a cold rolled sheet by primary cold rolling the hot rolled sheet; degreasing the cold rolled sheet; middle decarburizing annealing the cold rolled sheet, wherein the middle decarburizing annealing is carried out by heating the cold rolled sheet to 800° C. or higher in a protective atmosphere with P H2O /P H2 =0.50-0.88 for 8 minutes or shorter to reduce the carbon content to 30 ppm or less; shot blasting and acid washing for removing iron oxides from a surface of the cold rolled sheet to control the oxygen content to be 500 ppm or less; forming a steel sheet by secondary cold rolling the cold rolled sheet to a desired thickness; high-temperature annealing the steel sheet; and applying tension coating on the surface of the steel sheet and stretch-leveling annealing the steel sheet.