| 摘要 |
PROBLEM TO BE SOLVED: To provide a thick steel plate having satisfactory HIC resistance and DWTT properties, and inexpensively producible by suppressing elevated energy cost.SOLUTION: The thick steel plate has a chemical composition containing, by mass, 0.01 to 0.17% C, 0.01 to 0.60% Si, 0.4 to 1.8% Mn, ≤0.02% P, ≤0.01% S, 0.001 to <0.01% Nb, 0.001 to 0.06% Al, ≤0.01% N, ≤0.005% O, and the balance Fe with impurities, wherein a value expressed by expression of [C+(Mn/5)+5P-(Ni/10)-(Mo/10)+(Cu/10)] is 0.25 to 0.65, and has a microstructure in which the ratio of bainite is ≥90%. The thick plate may further contains predetermined amounts of one or more selected from Cu, Cr, Mo, V, Ti, Ni, B, Ca, Mg and REM. |
