| 摘要 |
<p>PURPOSE:To increase the thickness of a residual compressive stress layer and to increase the residual compressive stress value by subjecting a metallic material to a peening treatment, heat treatment and peening treatment and subjecting further repeatedly the material to the heat treatment and the peening treatment. CONSTITUTION:The metallic material is subjected to the peening treatment under the condition of about 0.20mmA arc height value to increase the thickness of the residual compressive stress layer. The material is subjected to the heat treatment at 100-300 deg.C to fix the movable dislocation of the residual compressive stress layer after the above-mentioned 1st stage of the treatment and thereafter the material is subjected to the 2nd stage of the treatment for age hardening. The material is subjected to the peening treatment under the condition of the arc height value lower than in the 1st stage to increase the residual compressive stress value on the surface of the residual compressive stress layer as the 3rd stage. The material is subjected to the 2nd stage of the heat treatment and the 3rd stage of the peening treatment repeatedly successively to the above. The residual compressive stress layer having the excellent residual compressive stress distribution is formed by the above-mentioned method, by which the fatigue resistant characteristic, stress corrosion resistance characteristic, etc., of the metallic material are improved.</p> |
