| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high strength coil spring excellent in fatigue strength and settling resistance and suitable for, for example, a valve spring for an automobile engine and a spring for a transmission, and a method of manufacturing such the coil spring. <P>SOLUTION: A steel composed of, by mass%, >0.5 to 0.9% C, 0.8-3.5% Si, 0.3-3.0% Mn, and 0.5-3.5% Cr, and when necessary, further, 0.05-1.5% Ni, and at least one kind of elements selected from group composed of 0.05-1.5% Mo, 0.05-0.5% V and 0.01-0.5% Nb, and the balance Fe with inevitable impurities, is used for the coil spring, and by a carburizing-treatment, a carburized and hardened layer having depth of 0.05-1.00 mm is formed, and hardness at the position of 0.02 mm from the surface is controlled to 650-1,000 Hv. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
