Grain-oriented electrical steel sheet, wound transformer core using the same, and method for producing wound core

Abstract

A grain-oriented electrical steel sheet for a wound transformer core. The steel sheet having a sheet thickness t, where t and an iron loss deterioration ratio obtained by subjecting the steel sheet under elliptic magnetization satisfy the following relations: (i) when t≤0.20 mm, the iron loss deterioration ratio is 60% or less; (ii) when 0.20 mm<t<0.27 mm, the iron loss deterioration ratio is 55% or less; and (iii) when 0.27 mm≤t, the iron loss deterioration ratio is 50% or less. The iron loss deterioration ratio is calculated from ((W−W)/W)×100, where Wis iron loss under 50 Hz elliptic magnetization of 1.7 T in a rolling direction and 0.6 T in a direction orthogonal to the rolling direction, and Wis iron loss under 50 Hz alternating magnetization of 1.7 T in the rolling direction.