| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a steel for a high strength spring, high in strength and excellent in hydrogen embrittlement resistance capable of obtaining excellent delayed fracture resistance and corrosion fatigue fracture resistance. <P>SOLUTION: The steel for a high strength spring, excellent in hydrogen embrittlement resistance includes, by mass%, 0.40-0.65% of C, 1.8-3.0% of Si, 0.1-0.5% of Mn, 0.010% or less of P, 0.015% or less of S, 0.5% or less of Cr and 0.01-0.5% of V, with the remainder being Fe and inevitable impurities. In the steel for a high strength spring, a ratio of a maximum concentration of Mn to a minimum concentration of Mn in a region from a surface to a depth of 1 mm is 1.5 or less, and an amount of non-diffusible hydrogen is less than 0.3 ppm. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
