Patent ID: 9659693
Date: 2017-05-23
CPC Classifications: C21D,C22C,H01F

Claim:
1. A manufacturing method of a grain-oriented electrical steel sheet, comprising: cold-rolling a silicon steel sheet containing Si; next, performing a decarburization annealing of the silicon steel sheet so as to cause a primary recrystallization; next, coiling the silicon steel sheet so as to obtain a steel sheet coil; next, performing an annealing of the steel sheet coil through batch processing so as to cause a secondary recrystallization; and next, uncoiling and flattening the steel sheet coil, wherein the manufacturing method further comprising, between the cold-rolling the silicon steel sheet containing Si and the coiling the silicon steel sheet so as to obtain the steel sheet coil, irradiating a laser beam a plurality of times at a predetermined interval in a rolling direction on a surface of the silicon steel sheet from one end to the other end of the silicon steel sheet along a sheet width direction, and while the secondary recrystallization is caused, grain boundaries passing from a front surface to a rear surface of the silicon steel sheet are generated along paths of the laser beams, wherein, when an average intensity of the laser beam is P (W), a size in the rolling direction and a size in the sheet width direction of a focused beam spot of the laser beam are Dl (mm) and Dc (mm), respectively, and a local power density of the laser beam is Ip=4/π×P/(Dl×Dc), the following relation is satisfied,