The high intensity which is superior in resistance high tension hydrogen environmental embrittlement characteristic the low-alloy steel and its production mannered

摘要

PPROBLEM TO BE SOLVED: To inexpensively provide a low alloy steel showing high strength and excellent embrittlement resistance to a high-pressure hydrogen environment under the high-pressure hydrogen environment. PSOLUTION: This low alloy steel has a composition comprising, by mass%, 0.10 to 0.20% C, 0.10 to 0.40% Si, 0.50 to 1.20% Mn, 0.005% or less P, 0.002% or less S, 0.75 to 1.75% Ni, 0.20 to 0.80% Cr, 0.10 to 0.50% Cu, 0.10 to 1.00% Mo, 0.01 to 0.10% V, 0.0005 to 0.005% B, 0.01% or less N, further one or two elements of 0.01 to 0.10% Nb and 0.005 to 0.050% Ti and the balance Fe with unavoidable impurities. The manufacturing method includes smelting a low alloy steel having the above composition and thermally refining it to control a tensile strength in the atmosphere to 900 to 950 MPa. PCOPYRIGHT: (C)2010,JPO&INPIT