Patent ID: 9139886
Filing Date: 2015-09-22
Classification: B23K,C21D,Y10T

Abstract:
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 μm 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/mm the power density Pd [W/mm