Patent ID: 7883586

Claim:
A method of production of a grain-oriented electrical steel sheet excellent in magnetic properties, comprising focusing a laser beam in an elliptical spot having constant long axis and short axis on said grain-oriented electrical steel sheet, said grain-oriented electrical steel sheet moving at a predetermined speed, and scanning and irradiating the grain-oriented electrical steel sheet in the width direction by the focused elliptical spot to improve the magnetic properties, said method of production of grain-oriented electrical steel sheet characterized by providing a slant angle θs between a scan direction of said elliptical spot and a long axis direction of the elliptical spot, wherein said slant angle θs is determined in accordance with a production line speed Vl of the grain-oriented electrical steel sheet and a scan speed Vc of the elliptical spot of the laser beam on the grain-oriented electrical steel sheet, based on the following equation (1): θ s =tan −1 ( Vl/Vc ) (1).