| 摘要 |
PROBLEM TO BE SOLVED: To provide a high damping alloy for a low Cr structural material in which damping properties and strength-toughness are reconciled. SOLUTION: In steel having a compsn. contg., by weight, <=0.03% C, 0.01 to 3.5% Si, 0.3 to 3.0% Mn, <=0.02% P, <=0.010% S, 0.01 to 5.0% Cr, 0.002 to 3.5% Al and <=0.01% N, if required, added with one or >= two kinds among Cu, Ni, Mo, W, Nb, Ta, V, Ti, Zr, B, Ca, Mg and rare earth metals in suitable ranges, and consisting of the balance Fe with inevitable impurities, as to the surface and back faces of the steel sheet, respectively, the average ferrite grain size to 1/6 sheet thickness in the sheet thickness from the surface is controlled to 70 to <150μm, the average ferrite grain size at the inside of the steel sheet other than the regions is controlled to 20 to <50μm, also, the (200) plane intensity ratio of the ferrite phase by X-ray diffraction measured at the part of 1/8 sheet thickness in the sheet thickness direction from the surface is controlled to >=1.5, and the (200) plane intensity ratio by X-ray diffraction measured at the center part of the sheet thickness is controlled to >=3.0, by which its damping properties and toughness are reconciled.
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