| 摘要 |
<p>PURPOSE: To provide a crude oil tank in which the whole crude oil tank comprising welding coupling shows almost similar excellent corrosion resistance under corrosion environment of oil tanks, and which is capable of inhibiting production of corrosion products (sludge) including solid sulfur. CONSTITUTION: In forming a crude oil tank by welding to each other steel members comprising 0.001 to 0.2 wt.% of C, 0.01 to 2.5 wt.% of Si, 0.1 to 2 wt.% of Mn, 0.03 wt.% or less of P, 0.02 wt.% or less of S, 0.01 to 1.5 wt.% of Cu, 0.001 to 0.3 wt.% of Al, 0.001 to 0.01 wt.% of N, 0.01 to 0.5 wt.% of Mo or/and 0.01 to 1 wt.% of W, and a balance of Fe and inevitable impurities, the crude oil tank having welding coupling excellent in corrosion resistance is characterized in that Cu, Mo and W contents of welding metal in a welding coupling part satisfy the following expressions 1 and 2: £Expression 1|, 3>=Cu content(mass%) of welding metal/Cu content(mass.%) of steel members>=0.15; £Expression 2|, 3>=£Mo content of welding metal+W content(mass.%)|/£Mo content of steel members+W content(mass.%)|>=0.15.</p> |
