| 摘要 |
PURPOSE:To produce a surface-treated steel sheet for can making having excellent adhesiveness of a coated film by subjecting the surface of the steel sheet to Sn plating then to a chromate treatment with a chromate treatment liquid having a specific compsn. CONSTITUTION:The steel sheet which is a stock for can making is subjected to Sn plating to <=1,500mg/m<2> per side and further the plated surfaces of the Sn plated steel sheet are heated to the melting temp. of Sn or above to melt the Sn plating layer by which an Fe=Sn alloy layer is formed. The steel sheet is then subjected to the chromate treatment. The compsn. of the chromate treatment coating layer is so adjusted that the content Xmg/m<2> of oxide chromium to be dissolved when immersed into a hot alkali and the total chromium content Ymg/m<2> to be measured by fluorescence X-rays, etc. attain X>=10mg/m<2> and 10mg/m<2Y<=30mg/m<2>. The plating layer of <=100mg/m<2> in terms of Ni as underlying plating contg. Ni or Ni and >=1 kinds among Fe, P, Zn, and Cr is formed on the steel sheet prior to the Sn plating treatment or the plating layer is heated to be diffused into the steel sheet for better results.
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