| 摘要 |
<p>Steel for crude oil tanks such as tanker oil tanks excelling in both resistance to uniform corrosion on the upper plate of the crude oil tank and resistance to local corrosion on the bottom plate of the crude oil tank is provided by: the steel having a component composition containing, in mass%, C: 0.03-0.18%, Si: 0.03-1.50%, Mn: 0.1-2.0%, P: 0.013% or less, S: 0.010% or less, Al: 0.005-0.10%, N: 0.008% or less and Cu: 0.05-0.4% with the remainder being obtained from Fe and unavoidable impurities; and in the above P content range, the Cu content and S content of the steel being adjusted to ranges that satisfy the relationship in formula (1) [%S] ≤ 0.077 × [%Cu]0.1 - 0.056 (1) wherein [%S] and [%Cu] are the S and Cu contents (mass%) in the steel.</p> |
