| 摘要 |
Disclosed are: a welded joint which is capable of significantly reducing overall corrosion or local corrosion that occurs in a crude oil tank; and a crude oil tank which comprises the welded joint. Specifically disclosed is a crude oil tank that comprises a welded joint which is formed by welding steel materials each containing, in mass%, 0.03-0.16% of C, 0.05-1.50% of Si, 0.1-2.0% of Mn, 0.025% or less of P, 0.010% or less of S, 0.005-0.10% of Al, 0.008% or less of N, more than 0.1% but 0.5% or less of Cr and 0.03-0.4% of Cu, and additionally containing one or more elements selected from among 0.01-1.0% of W, 0.01-0.5% of Mo, 0.001-0.2% of Sn and 0.001-0.4% of Sb. The welded joint is also characterized in that Cu, Mo and W in the welded metal satisfy the following relations: 3 < (Cu in the welded metal)/ (Cu in the matrix) = 7 and 1 = (Cu in the welded metal)/{(Mo + W) in the welded metal} = 10. |
