| 摘要 |
<p>This process for producing an oriented electromagnetic steel sheet involves, between a cold-rolling step and a winding step, a groove formation step of irradiating the surface of a silicon steel sheet with a laser beam several times at predetermined intervals in the direction of passing of the beam through the silicon steel sheet (the beam-passing direction) started from one end of the silicon steel sheet in the direction of the width of the silicon steel sheet (the sheet width direction) and ended at the other end of the silicon steel sheet to thereby form a groove along the trajectory of the laser beam, wherein formulae (3) and (4) mentioned below are fulfilled, in which P (W) represents the average intensity of the laser beam, Dl (mm) and Dc (mm) respectively represent the focused spot diameter as determined in the beam-passing direction and the focused spot diameter as determined in the sheet width direction of a focused spot of the laser beam, Vc (mm/s) represents the scanning velocity of the laser beam in the sheet width direction, Up represents the irradiation energy density of the laser beam which is represented by formula (1), and Ip represents the instant power density of the laser beam which is represented by formula (2). Up = (4/p)×P/(Dl×Vc) (formula 1) Ip = (4/p)×P/(Dl×Dc) (formula 2) 1 = Up = 10(J/mm2) (formula 3) 100(kW/mm2) = Ip = 2000(kW/mm2) (formula 4)</p> |
