HIGH-STRENGTH LOW-ALLOY STEEL EXCELLENT IN THE RESISTANCE TO HIGH-PRESSURE HYDROGEN ENVIRONMENT EMBRITTLEMENT AND PROCESS FOR MANUFACTURING THE STEEL

摘要

PROBLEM TO BE SOLVED: To provide at a low cost a low-alloy steel which shows a high strength in a high-pressure hydrogen environment and is excellent in resistance to high-pressure hydrogen environment embrittlement.;SOLUTION: The low-alloy high-strength steel has a composition comprising, by mass%, 0.10-0.20% C, 0.10-0.40% Si, 0.50-1.20% Mn, ≤0.005% P, ≤0.005% S, 0.20-0.80% Cr, 0.10-0.50% Cu, 0.10-1.00% Mo, 0.01-0.10% V, 0.0005-0.005% B, ≤0.01% N and the balance being Fe and unavoidable impurities. The material with a high strength and a low sensitivity to hydrogen environment embrittlement can be obtained by melting a low-alloy steel having the above composition and thermally refining the same so as to achieve a tensile strength of 900-950 MPa in the atmosphere.;COPYRIGHT: (C)2009,JPO&INPIT