Patent ID: 8790471

Claim:
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 when an average intensity of the laser beam is P (W), a size in the rolling direction of a focused beam spot of the laser beam is Dl (mm), a scanning rate in the sheet width direction of the laser beam is Vc (mm/s), and an irradiation energy density of the laser beam is Up=4/π×P/(Dl×Vc), the following relation is satisfied so as to create grain boundaries passing from a front surface to a rear surface of the silicon steel sheet along paths of the laser beams while the secondary recrystallization is caused, 0.5 J/mm 2 ≦Up≦ 20 J/mm 2 .