GRAIN-ORIENTED ELECTRICAL STEEL SHEET, WOUND TRANSFORMER CORE USING THE SAME, AND METHOD FOR PRODUCING WOUND CORE

摘要

Provided is a directional electrical steel sheet which is excellent in the reduction effect of transformer core loss when used for a wound core of a transformer. In the directional electrical steel sheet for use in a wound core of a transformer, the thickness t of the steel sheet and the iron loss deterioration rate when the steel sheet is subjected to elliptical magnetization defined by the following formula (1) satisfy the following relationship. When the thickness t = 0.20 mm, the iron loss deterioration rate is 60% or less, when 0.20 mm t 0.27 mm, the iron loss deterioration rate is 55% or less, and when 0.27 mm = t, the iron loss deterioration rate is 50% or less (iron loss deterioration rate when elliptical magnetization is applied) = ((WA - WB)/WB) × 100 ... (1). In the formula (1), WA is iron loss in the case where 50 Hz elliptical magnetization of 1.7 T and 0. 6 T is applied in the RD direction (rolling direction) and TD direction (perpendicular to the rolling direction), respectively, and WB is iron loss in the case where 50 Hz alternating magnetization of 1.7 T is applied in the RD direction.