METHOD OF PRODUCING LOW IRON LOSS, LOW-NOISE GRAIN-ORIENTED SILICON STEEL SHEET, AND LOW-NOISE STACKED TRANSFORMER

摘要

A grain oriented silicon steel sheet which exhibits reduced iron loss and which contributes excellent noise characteristics when used as a material of a stacked transformer. The sheet is produced by applying electron beam irradiation to a finish-annealed grain oriented silicon steel sheet, along scan paths which cross the rolling direction at a scanning speed V(cm/s) and a spacing L(cm) in the rolling direction, with an electron beam of a beam diameter d (cm) generated by a current Ib (mA) and acceleration voltage Vk (KV); wherein the surface energy density a (J/cm2) on the surface of said steel sheet as determined by the following formula (1) is about 0.16 J/cm or more, and said surface energy density a (J/cm2) and the surface energy density .beta. (J/cm2) on the scan paths meet the approximate condition of the following formula (3): .alpha. = (Vk .beta. = (Vk 0.6 - 0.06.beta. Disclosed also is a stacked transformer produced from this grain oriented silicon steel sheet.