CORE-LOSS IMPROVING DEVICE AND CORE-LOSS IMPROVING METHOD FOR GRAIN-ORIENTED MAGNETIC STEEL SHEET

WIPO Patent Application WO/2012/001965

A1

Disclosed are a device and a method, by which it is possible to solve the problem of dust, prevent reduction in laser irradiation capability due to contamination, and reliably reduce the core loss of a grain-oriented magnetic steel sheet. When reducing the core loss of the magnetic steel sheet by irradiating the surface of the grain-oriented magnetic steel sheet which is finally annealed with laser, a laser radiation point is arranged at a position where, when the distance between the laser radiation point in an irradiation device of the laser, and a laser irradiation point on the steel sheet is set as L (mm), and the angle between a straight line connecting the laser radiation point and the laser irradiation point and the vertical direction is set as θ (˚), L is 50 or more, and further in the case of L≤100, 60-0.3L≤θ≤60 is obtained, in the case of 100