| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an extra-thin silicon steel sheet which is less in the quantity of coarse grains even when being subjected to heat treatment at ≥1,100°C, has high B8/Bs and is suitable to siliconizing treatment, and to provide a manufacturing method therefor,. <P>SOLUTION: This extra-thin silicon steel sheet having 0.03-0.10 mm sheet thickness, is obtained by re-rolling a unidirectional silicon steel secondary recrystallized sheet containing 2-4 mass% of recompression. The peculiarity is that the ratio of the coarse grain exceeding 5 times of the sheet thickness to the maximum width of crystallized grains is ≤15% after applying the heat-treatment under condition of temperature of 1,100°C for 1 minute during the nitrogen atmosphere and B8/Bs is ≥0.85. When this steel sheet is manufactured, on the surface of the unidirectional silicon steel secondary recrystallized sheet before re-rolling, for example, a mechanical-grinding or a chemical-corrosion is applied, and after making an arithmetic means Ra of the surface roughness from 0.6 μm to <3.5 μm, the re-rolling is applied. <P>COPYRIGHT: (C)2010,JPO&INPIT |
