| 摘要 |
PROBLEM TO BE SOLVED: To provide a high tensile strength marine steel exhibiting corrosion resistance effective even if not being subjected to coating and electrolytic protection (particularly, excellent durability to crevice corrosion in a wet air atmosphere of the upper part in a ballast tank, the upper deck plate of a crude oil tank or the like on which electrolytic protection is not acted), and further exhibiting excellent base metal toughness. SOLUTION: The marine steel has a composition comprising, by mass, 0.01 to 0.2% C, 0.01 to 0.5% Si, 0.01 to 2% Mn, 0.05 to 0.5% Al, 0.010 to 1.5% Cu and 0.010 to 1% Cr, in which the content of P is suppressed to≤0.02% (exclusive of 0%) and the content of S is suppressed to≤0.01% (exclusive of 0%), respectively, and the balance Fe with inevitable impurities, and in which the fraction of insular martensite is≤1.1%, and the balance bainitic structure. COPYRIGHT: (C)2007,JPO&INPIT
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