Grain-oriented electrical steel sheet excellent in film characteristics and magnetic characteristics, process for producing same, and decarburization annealing facility used in same process

摘要

A grain-oriented electrical steel sheet excellent in film and iron loss characteristics. The steel sheet contains up to 0.005% of C, 2.0 to 7.0& Si in terms of weight % and the balance iron and unavoidable impurities. An oxide film which mainly contains forsterite is formed on the surface and an insulating coating is formed on the oxide film. The peak intensity of Si obtained by glow discharge spectral analysis (GDS analysis) from the oxide film surface is at least ½ of that of Al, and the depth of the peak position of Si from the oxide film surface us up to {fraction (1/10 of the depth of that of Al. The sheet satisfies the formulas for a ratio y(%) with which peeling of the oxide film does not take place when subjected to a bending test with a curvature of 20 mm and for core loss characteristic W (W/kg):wherein t represents a sheet thickness in terms of mm.