Wound core

A wound core comprising:

• a substantially rectangular wound core main body in a side view,
• wherein the wound core main body includes a portion in which grain-oriented electrical steel sheets in which first planar portions and corner portions are alternately continuous in a longitudinal direction and an angle formed by two first planar portions adjacent to each other with each of the corner portions therebetween is 90° are stacked in a sheet thickness direction and has a substantially rectangular laminated structure in a side view,
• wherein each of the corner portions has two or more bent portions having a curved shape in a side view of the grain-oriented electrical steel sheets and a second planar portion between the adjacent bent portions, and the sum of bent angles of the bent portions existing in one corner portion is 90°,
• wherein each bent portion in a side view has an inner side radius of curvature r of 1 mm to 5 mm,
• wherein the grain-oriented electrical steel sheets have a chemical composition containing, in mass %,
• Si:
• 2.0% to 7.0%, with the remainder comprising Fe and impurities, and
• have a texture oriented in the Goss orientation, and
• wherein at least one of two or more bent portions existing in at least one corner portion satisfies Equations (1) to (3) below,
• Tave≤40 nm (1)
• (To−Tu)/Tave≤0.50 (2)
• Tave(To−Tu)≤240 nm2 (3)
• here, a thickness T (nm) of an intermediate layer provided on a surface of a base steel sheet of the grain-oriented electrical steel sheets is measured at multiple sites of the first and second planar portion regions adjacent to the bent portions, an average thickness of the thickness T (nm) of the intermediate layer is regarded as Tave (nm), a maximum thickness is regarded as Tmax (nm), a minimum thickness is regarded as Tmin (nm), an average value of data where T>Tave is regarded as To (nm), and an average value of data where T<Tave is regarded as Tu (nm).