| 摘要 |
<p>Disclosed is a coated steel sheet valuable for the production of a fuel vessel, in which a first covering layer comprising a Pb-Sn alloy as the main component is formed on a substrate comprising a steel sheet and an undercoat covering layer composed of at least one member selected from Ni, Co and Cu, which is formed on the surface of the steel sheet according to need, a second covering layer containing a compound containing Pb and P is formed on the first covering layer, a third covering layer containing at least one member selected from Sn, Ni and Co is formed on the second covering layer, and according to need, the surface portion of the third covering layer is modified with a treating liquid containing a phosphoric acid ion or a chromic acid ion. This coated steel sheet shows a highly improved corrosion resistance, forming processability, solderability, and weldability.</p> |
