Crude oil tank steel and crude oil tank

摘要

0.03 to 0.1% of Si, 0.03 to 1. 0% of Si, 0.1 to 2.0% of Mn, 0.025% or less of P, 0.010% or less of P, 0.010% or less of S, 0.005 to 0.10% of Al, 0.001% or less N and 0.005% or less Cu and 0.05% to 0.4% Cu, the balance being Fe and inevitable impurities, and the dislocation density of the steel material is expressed by the following formula (1) in relation to the Cu content: 4 10¹⁶ [% Cu]^2.8 ---(1) However, [% Cu] represents the Cu content (mass%) in the steel material, The steel material for a crude oil tank is excellent in both the corrosion resistance in the upper plate of a crude oil tank such as a tanker oil tank portion and the local corrosion resistance in the bottom plate of a crude oil tank.