| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a non-oriented electrical steel sheet having low core loss in a high-frequency region as well as in a low-frequency region by means of a technique different from the addition of specific-resistance-increasing elements and the reduction of sheet thickness. <P>SOLUTION: In the non-oriented electrical steel sheet, ≤4 mass% Si is contained and the size of crystalline grains is smaller in the surface layer part of the steel sheet than in the inner part of the steel sheet. This steel sheet has the following characteristics: when a fine crystalline grain region is defined as the steel-sheet surface layer part where the average crystalline grain size Dz in a sheet-thickness direction z is ≤1.5 times the minimum value Dmm of the above grain sizes and a coarse crystalline grain region is defined as the remaining inner part of the steel sheet, the thickness of the fine crystalline grain region per side is 8 to 25% of the whole sheet thickness and the average crystalline grain size in the fine crystalline grain region is 2 to 70% of that in the coarse crystalline grain region. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
