| 摘要 |
PURPOSE:To reduce the generation of crack on a rim side and consequently improve the durability of the disc wheel by a method wherein a surface treatment by shot peening is applied on the rim side of a weld bead, which is applied to the junction between the rim and a disc of the vehicular disc wheel. CONSTITUTION:Because the existence of a depression caused by the final end part or a part of boundary line of rim 1 side of weld bead 11 together with a corner 5 so as to form a notch 12 develops the possibility of the generation of cracks 13 in the vicinity of the notch 12, ring-shape shot-peening treatment is applied from a nozzle 15 along the peripheral surface onto a surface 14 near the boundary line of the rim side weld zone of the weld bead. Even if a notch 12 or an unhomogeneous part is generated by welding, the tensile stress generated at the rim 1 and the weld bead during the running for a long period of time can be relieved because of the residual compression stress developed at said rim 1 and weld bead 11 by shot-peening action. |
