| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide automotive undercarriage parts having excellent fatigue characteristics and also to provide a method for improving fatigue strength thereof. <P>SOLUTION: The automotive undercarriage parts with excellent fatigue characteristics are composed of hot forged non-heat treated steel which has a composition consisting of, by mass, 0.1 to 0.8% C, 0.05 to 2.5% Si, 0.2 to 3% Mn, 0.005 to 0.1% Al, 0.001 to 0.02% N and the balance Fe with inevitable impurities and has≥600 MPa tensile strength and a ferrite-pearlite structure. The residual compressive stress in the neck part surface layer of the undercarriage parts is 50 to 80% of the tensile strength of the hot forged non-heat treated steel. The method for improving the fatigue strength of the parts is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
