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

A grain-oriented electrical steel sheet which has excellent film characteristics and magnetic characteristics,

• comprising up to 0.005% of C, 2.0 to 7.0% of Si in terms of weight % and the balance Fe and unavoidable impurities,
• having an oxide film which mainly contains forsterite and is formed on the surface, and an insulating coating formed on the oxide film,
• wherein the amount of the oxide film is from 1 to 4 g/m2 per side, and the depth of the peak position of Si from the oxide film surface, obtained by glow discharge spectral analysis (GDS analysis) is up to {fraction (1/10)} of the depth of that of Al, and
• showing 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 which satisfies the following formula (1):
• y(%)≧−122.45t+112.55 (1)
• wherein t represents a sheet thickness in terms of mm, and iron loss characteristics W (W/kg) which satisfy the following formula (2):
• W (W/kg)≦2.37t+0.280 (2)
• wherein t represents a sheet thickness in terms of mm.