MAGNETIC DOMAIN REFINEMENT METHOD FOR GRAIN-ORIENTED ELECTRICAL STEEL SHEET, MAGNETIC DOMAIN REFINEMENT APPARATUS, AND GRAIN-ORIENTED ELECTRICAL STEEL SHEET MANUFACTURED BY MEANS OF SAME

摘要

Disclosed is a magnetic domain refining method for radiating a laser beam to a surface of a directional electrical steel plate at intervals, which is capable of further reducing noise along with an iron loss reduction effect and further improving iron loss and noise reduction effects in an area where the directional electrical steel plate are bonded together, such as the joint part of the iron core of a transformer. Irradiated radiations formed by a laser beam in at least any one area of the directional electrical steel plate are unfolded in a fan rib form using one point of the directional electrical steel plate as a central point.