| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a steel having high strength of ≥550 MPa tensile strength, which is excellent in toughness and suitable to be used in a high-pressure hydrogen environment, such as a hydrogen storing vessel and an accumulator installed in a hydrogen station or the like. <P>SOLUTION: This steel contains, by mass, 0.05-0.12% C, 0.01-0.50% Si, >0.6 and ≤1.8% Mn, ≤0.02% P, ≤0.003% S, 0.01-0.08% Al, optionally ≤0.3% Cr, optionally ≤0.3% Mo, and optionally one or two or more kinds selected from Cu, Ni, Nb, V, Ti, B and Ca, with the remainder comprising Fe and incidental impurities, wherein a metal structure is a structure mainly composed of bainite whose area fraction is ≥90%, and cementite having an average particle size of ≤50 nm and an average aspect ratio of ≤3 is dispersed and deposited in the bainite. <P>COPYRIGHT: (C)2012,JPO&INPIT |
