| 摘要 |
PURPOSE:To provide a titled steel consisting of the specific compsn. which is decreased in the content of C in a Cr-Mo steel, is added with a low content of Nb and V and is associated overall in the contents of C, Mo, Nb and V. CONSTITUTION:A high-strength high-temp. steel having the compsn. contg. 0.04- 0.07wt% C, 0.16-0.50% Si, 0.30-0.160% Mn, 8.00-9.50% Cr, 0.85-1.05% Mo, 0.15-0.25% V, and 0.06-0.10% Nb, and consisting of the balance Fe and unavoidable impurities and having excellent weldability is the 9Cr-1Mo steel with which the generation of low-and high-temp. cracking particularly in the weld zone is small and which is provided with extremely high strength at both ordinary and high-temp. and low-temp. toughness. The value of the formula 4(50C%- Mo%+6Nb%-1) is preferably made as small as possible within a permissible range in order to prevent more surely the high temp. cracking.
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