Cu Cu CONTAINING LOW ALLOY STEEL HAVING EXCELLENT TOUGHNESS OF WELD HEAT AFFECTED ZONE AND METHOD FOR PRODUCING THEREOF

摘要

[Problem] To provide a low-alloy steel containing Cu having excellent low-temperature toughness. [Solution means] In mass%, C: 0.01 to 0.06%, Si: 0.05 to 0.40%, Mn: 0.20 to 0.70%, Ni: 1.20 to 2.50%, Cr: 0.50 to 1.00%, Cu: 0.80 to 1.50%, Mo: 0.20 to 0.60%, Al: 0.010 to 0.050%, Nb: 0.020 to 0.080%, N: 0.005 to 0.020%, Ca: 0.010% or less as desired, the balance being Fe and unavoidable impurities It has a chemical composition consisting of