| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a coil spring which can stably show high fatigue characteristics. Ž<P>SOLUTION: The method for manufacturing the coil spring includes: a forming step of forming the coil spring by employing an oil-tempered alloy-steel wire as a raw material; a nitriding treatment step of enhancing the surface hardness of the coil spring; and a shot peening step of imparting residual stress to the coil spring. The method further includes electrolytically polishing the coil spring after the shot peening step to remove the surface layer of the coil spring, control the thickness of a white layer formed in the nitriding treatment step to 5 μm or less, simultaneously control the surface roughness to 4 μm or less by Rc and also control the compressive residual stress of the outermost surface to 1,800 MPa or higher. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
