| abstract |
A low-alloy steel is produced through a process of in the smelting of low-alloy steel of composition comprising 0.1 to 0.55% C, 0.05 to 0.5% Si, 0.1 to 1% Mn, 0.0001 to 0.005% S, 0.005 to 0.08% Al, 0.005 to 0.05% Ti, 0.1 to 1.5% Cr, 0.1 to 1% Mo, 0.0004 to 0.005% O, 0.0005 to 0.0045% Ca, 0 to 0.1% Nb, 0 to 0.5% V, 0 to 0.005% B, 0 to 0.10% Zr, P≤0.03%, N≤0.006% and the balance of Fe and impurities, regulating [Ti], [N] and [Ca] respectively representing the contents by mass% of Ti, N and Ca in molten steel so as to satisfy the relationship 0.0066 ≥ ([Ti]/47.9)([N]/14)/([Ca]/40.1) ≥ 0.0008. The thus obtained low-alloy steel exhibits a yield stress of ≥ 758MPa, having high SSC resistance. |