| 摘要 |
<p>PURPOSE:To improve the fatigue strength of the notched part of a metallic material by heating the vicinity of the notched part, cooling a part around the vicinity, cooling the heated part, and heating the cooled part to produce compressive residual stress in the vicinity of the notched part. CONSTITUTION:The vicinity of the notched part which is hole parts and notches etc., provided to a metallic material is heated, and a part around the vicinity is forced to be cooled by spraying liquefied gas at low temp. or water to produce sufficient tensile residual stress in the vicinity of the notched part. The cooled part is then heated, and the heated part is forced to be cooled to produce compressive residual stress in the vicinity of the notched part. By this method, the compressive residual stress can be produced without deforming the metallic material or changing the quality of the material and the fatigue strength of the notched part can be improved.</p> |
