| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet for a vessel, which retains adequate weldability even without grinding a part to be welded like in tin-free steel and an appearance near to the tin-free steel, has superior corrosion resistance to an Sn-dissolving content like strong alkali, and further has equal adhesiveness to paint to an existing electrolytically chromated coating, in spite of being a chromium-free raw material. SOLUTION: The surface-treated steel sheet for the vessel having superior weldability, corrosion resistance, and adhesiveness to paint has a coating of 100 mg/m<SP>2</SP>to 10 g/m<SP>2</SP>having a structure comprising sequentially an Fe-Ni diffusion layer, a Ni layer, a Ni-Sn alloy layer and an unalloyed Sn layer, from the steel sheet side, wherein the quantity of the unalloyed tin in the coating is 0.1-10 mg/m<SP>2</SP>or less. Thereby, the steel sheet becomes usable for the content which may react with tin to cause a trouble, while securing the appearance and the weldability. Furthermore, the plated film structure consisting of the above layers has equal characteristics such as adhesiveness to paint and corrosion resistance after being painted to the electrolytically chromated coating, in spite of being a chromium-free material. COPYRIGHT: (C)2005,JPO&NCIPI
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