Grain-oriented electrical steel sheet and magnetic domain refining method therefor

Abstract

A grain-oriented electrical steel sheet according to an embodiment of the present invention includes: a groove on a line formed on one surface of an electrical steel sheet in a direction crossing a rolling direction; and a thermal shock portion on a line formed on one surface of the electrical steel sheet in the direction crossing the rolling direction, wherein a distance between the groove and the thermal shock portion is 1 mm or less.

1 . A grain-oriented electrical steel sheet, comprising:
 a groove on a line formed on one surface of an electrical steel sheet in a direction crossing a rolling direction; and   a thermal shock portion on a line formed on the other surface of the electrical steel sheet in the direction crossing the rolling direction,   wherein a distance between an imaginary line in which the groove is symmetrically projected onto the other surface with respect to a center of thickness of the steel sheet and the thermal shock portion is 1 mm or less.   
     
     
         2 . The grain-oriented electrical steel sheet of  claim 1 , wherein
 a depth of the groove is 1 to 10% of a thickness of the steel sheet.   
     
     
         3 . The grain-oriented electrical steel sheet of  claim 1 , wherein
 a plurality of grooves are formed, and a distance between the grooves is 1.5 to 10 mm.   
     
     
         4 . The grain-oriented electrical steel sheet of  claim 3 , wherein
 a plurality of the thermal shock portions are formed, and a distance between the thermal shock portions is 1 to 5 times the distance between the grooves.   
     
     
         5 . A magnetic domain refining method of a grain-oriented electrical steel sheet, comprising:
 preparing a grain-oriented electrical steel sheet;   forming a groove by irradiating a laser on one surface of the grain-oriented electrical steel sheet in a direction crossing a rolling direction; and   forming a thermal shock portion by irradiating a laser on one surface of the grain-oriented electrical steel sheet in the direction crossing the rolling direction,   wherein a distance between the groove and the thermal shock portion is 1 mm or less.   
     
     
         6 . A magnetic domain refining method of a grain-oriented electrical steel sheet, comprising:
 preparing a grain-oriented electrical steel sheet;   forming a groove by irradiating a laser on one surface of the grain-oriented electrical steel sheet in a direction crossing a rolling direction; and   forming a thermal shock portion by irradiating a laser on the other surface of the grain-oriented electrical steel sheet in the direction crossing the rolling direction,   wherein a distance between an imaginary line in which the groove is symmetrically projected onto the other surface with respect to a center of thickness of the steel sheet and the thermal shock portion is 1 mm or less.   
     
     
         7 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 5 , wherein
 in the forming of the groove, energy density of the laser is 0.5 to 2 J/mm 2 , and in the forming of the thermal shock portion, energy density of the laser is 0.05 to 0.2 J/mm 2 .   
     
     
         8 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 6 , wherein
 in the forming of the groove, energy density of the laser is 0.5 to 2 J/mm 2 , and in the forming of the thermal shock portion, energy density of the laser is 0.05 to 0.2 J/mm 2 .   
     
     
         9 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 5 , wherein
 in the forming of the groove, a beam length of the laser is 300 to 5000 μm in a rolling vertical direction of the steel sheet, and a beam width of the laser is 10 to 200 μm in a rolling direction of the steel sheet.   
     
     
         10 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 6 , wherein
 in the forming of the groove, a beam length of the laser is 300 to 5000 μm in a rolling vertical direction of the steel sheet, and a beam width of the laser is 10 to 200 μm in a rolling direction of the steel sheet.   
     
     
         11 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 9 , wherein
 in the forming of the thermal shock portion, a beam length of the laser is 1500 to 10,000 μm in a rolling vertical direction of the steel sheet, and a beam width of the laser is 100 to 1000 μm in a rolling direction of the steel sheet.   
     
     
         12 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 10 , wherein
 in the forming of the thermal shock portion, a beam length of the laser is 1500 to 10,000 μm in a rolling vertical direction of the steel sheet, and a beam width of the laser is 100 to 1000 μm in a rolling direction of the steel sheet.   
     
     
         13 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 5 , further comprising
 forming an insulating coating layer on a surface of the steel sheet.   
     
     
         14 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 6 , further comprising
 forming an insulating coating layer on a surface of the steel sheet.   
     
     
         15 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 13 , further comprising
 after the forming of the groove, forming an insulating coating layer on a surface of the steel sheet.   
     
     
         16 . The magnetic domain refining method of the grain-oriented electrical steel sheet of  claim 14 , further comprising
 after the forming of the groove, forming an insulating coating layer on a surface of the steel sheet.