Grain-oriented electrical steel sheet and method for producing same

摘要

In a method for producing a grain-oriented electrical steel sheet, grooves each having a given length and extending in a direction including a direction perpendicular to a transportation direction of the grain-oriented electrical steel sheet are formed at given intervals in the transportation direction by irradiating the surface of the grain-oriented electrical steel sheet with a laser beam while scanning the surface of the grain-oriented electrical steel sheet with the laser beam. Further, in the method for manufacturing a grain-oriented electrical steel sheet, the laser beam is a continuous-wave laser beam having a laser wavelength λ of 1.0 μm to 2.1 μm, power density Pd [W/mm2] which is obtained by dividing laser beam intensity P by a focused beam area S is 5×105 W/mm2 or more, and the power density Pd [W/mm2] and scanning speed V [mm/s] of a focused spot of the laser beam on the surface of the grain-oriented electrical steel sheet satisfy a relationship of 0.005×Pd+3000≦V≦0.005×Pd+40000.

主权项

1. A grain-oriented electrical steel sheet in which grooves each having a given length and extending in a direction intersecting a transportation direction are formed at given intervals in the transportation direction by a laser beam, the grain-oriented electrical steel sheet comprising:
a solidified layer provided on an interface with the groove; and a projection provided on a peripheral portion of the groove, wherein a depth of the groove is in a range of 8 μm to 30 μm, the cross-sectional area of the groove is less than 1000 μm2, and a height of the projection is 5 μm or less, wherein the grain-oriented electrical steel sheet is prepared in a method comprising, forming grooves each having a given length and extending in a direction intersecting a transportation direction of the grain-oriented electrical steel sheet, at given intervals in the transportation direction by irradiating a surface of the grain-oriented electrical steel sheet with a laser beam while scanning the surface of the grain-oriented electrical steel sheet with the laser beam, wherein the laser beam is a continuous-wave laser beam having a laser wavelength λ of 1.0 μm to 2.1 μm, a power density Pd [W/mm2] which is obtained by dividing a laser beam intensity P by a focused beam area S is 5×105 W/mm2 or more, and the power density Pd [W/mm2] and a scanning speed V [mm/s] of a focused spot of the laser beam on the surface of the grain-oriented electrical steel sheet satisfy a relationship of 0.005×Pd+3000≦V≦0.005×Pd+40000.