Method for producing tin-free steel sheets having improved lacquer adhesion.

摘要

Tin-free steel sheets are produced by chromium plating a thin steel sheet through cathodic electrolysis in a chromium-containing bath to deposit a metallic chromium layer, reversely electrolyzing the chromium plated steel sheet by a successive anodizing treatment in the same or another chromium-containing bath, and subjecting the reversely electrolyzed steel sheet to an electrolytic chromate treatment in an aqueous chromate solution. The adhesion of lacquer to the TFS sheet is improved by carrying out the electrolytic chromate treatment in a chromate solution which contains hexavalent chromium in an amount of 0.2 to 1.4 mols per liter of CrO3 and a fluoride in a molar ratio of F<-> to Cr<6><+> of <1>/1000 to <1>/20.