HIGH-STRENGTH STEEL MATERIAL HAVING EXCELLENT FATIGUE PROPERTIES AND METHOD FOR PRODUCING SAME

摘要

A high strength steel material excellent in fatigue characteristics and a method of manufacturing the steel material are provided. Wherein the composition comprises 0.10 to 0.20% of C, 0.50% or less of Si, 1.0 to 2.0% of Mn, 0.030% or less of P, 0.0005 to 0.0040% of S, : 0.0005 to 0.0050%, the balance being Fe and inevitable impurities, the ferrite having a metal structure as a main phase, and the second phase bainite and pseudo-pearlite.;