| 摘要 |
PROBLEM TO BE SOLVED: To provide Cr-Mo steel of a thick material having excellent toughness and excellent reheat cracking resistance even in severe using conditions requiring heat tretment after welding at high temperature for a ling time. SOLUTION: This Cr-Mo steel excellent in toughness and reheat cracking resistance has a composition containing, by mass, 0.03 to 0.15% C, 0.01 to 0.8% Si, <=1% Mn, <=0.015% P, <=0.003% S, 0.8 to 1.6% Cr, 0.2 to 1% Mo, 0.002 to 0.005% Ti, 0.0003 to 0.003% B, <=0.04% sol.Al, <0.0020% N and <=0.003% O, furthermore containing one or more kinds selected from Cu, Ni, Nb, Ca, Mg and rare earth metals, and the balance substantially Fe with inevitable impurities.
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