LOW ALLOY STEEL FOR HIGH PRESSURE HYDROGEN GAS ENVIRONMENT, AND VESSEL FOR HIGH PRESSURE HYDROGEN

摘要

PPROBLEM TO BE SOLVED: To provide a low alloy steel having excellent hydrogen environmental embrittlement resistance in spite of its high strength satisfying the tensile strength of 900 MPa. PSOLUTION: The low alloy steel for a high pressure hydrogen gas environment has a composition including, by mass, 0.15 to 0.60% C, 0.05 to 0.5% Si, 0.05 to 3.0% Mn, 0.025% P, 0.010% S, 0.005 to 0.10% Al, 0.5 to 3.0% Mo, 0.05 to 0.30% V, 0.01% O (oxygen) and 0.03% N, and the balance Fe with impurities, and whose tensile strength is 900 MPa. It is desirable that 0.0003 to 0.003% B is incorporated into the low alloy steel, but, in this case, the content of N is restricted to 0.010%. Further, one or more kinds selected from Cr, Nb, Ti, Zr and Ca are desirably incorporated therein. The contents of Mo and V are desirably allowed to satisfy the inequality (1): (1) [Mo(%)][V(%)]SP0.2/SP0.32. PCOPYRIGHT: (C)2009,JPO&INPIT