| abstract |
[Problem] To provide a high-strength low-alloy steel material having good SSC resistance. [Means for Solving] In mass%, C: 0.15 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.00. 05-3.0%, P: 0.025% or less, S: 0.010% or less, Al: 0.005-0.10% and O (oxygen): 0.01% or less, with the balance being A low alloy steel material comprising Fe and impurities, wherein the aspect ratio (major axis / minor axis) of prior austenite grains is 1.5 or more by cross-sectional observation. [Selection figure] None |