| 摘要 |
The present invention relates to a thick steel sheet having a sheet thickness of 30 mm or more, and provides a high-strength steel material having excellent fatigue properties and a method for producing the high-strength steel material. A high-strength steel material having excellent fatigue properties, said steel material having a chemical composition comprising, in mass%, 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, 0.002 to 0.07% of Sol.Al, 0.0005 to 0.0050% of Ca and a remainder made up by Fe and unavoidable impurities, wherein the metallic structure has the main phase composed of ferrite and the second phase composed of bainite and pseudo pearlite. |
