UNIDIRECTIONAL MAGNETIC STEEL SHEET EXCELLENT IN IRON LOSS CHARACTERISTIC

摘要

A unidirectional magnetic steel sheet excellent in iron loss to conventional is produced by dividing the iron loss of a unidirectional magnetic steel sheet into which strain is introduced by laser beam application into the hysteresis loss and the eddy current loss and quantitatively and adequately controlling the distributions including the direction of the sheet thickness of the strain and the residual stress in view of the eddy current loss. By applying a laser beam or the like, linear strain generally perpendicular to the rolling direction is introduced into a unidirectional magnetic steel sheet uniformly in the direction of the sheet thickness and periodically in the rolling direction to control the magnetic domains. The strain is so introduced that the integral of the compression residual stress in the rolling direction computed in the region of the cross-section where the compression residual stress is present lies in a predetermined range, in the two-dimensional distribution of the residual stress in the rolling direction caused near one strain-introduced portion in the cross-section perpendicular to the direction of the sheet width.