| 摘要 |
PROBLEM TO BE SOLVED: To obtain a surface-treated steel sheet which has the excellent corrosion resistance of processed parts on flawed parts not obtainable with only the self-repair effect by hexed chromium and further the surface-treated steel sheet which is excellent in the corrosion resistance of the processed parts, the blackening resistance under a moist environment or the corrosion resistance of the processed parts and the blackening resistance in a stacked state. SOLUTION: The film, in which (A) the chromium is included at 0.1 to 100 mg/2, (B) calcium is included at 0.1 to 200 mg/2 and (C) a compound consisting of either one or two kinds of zinc and aluminum is included in a range of 0.1 to 100 mg/2 in terms of phosphorus, is formed on the surface of the galvanized steel sheet. This film is formed by applying a treating liquid which is a treating liquid containing the water-soluble chromium compound, the calcium and the phosphoric acid and containing (i) 0.1 to 50 g/l hexad chromium ions, (ii) 1 to 50 gel calcium and (iii) 1 to 50 g/l phosphoric acid in the treating liquid described above on the surface of the galvanized steel sheet and heating the steel sheet to a range of the ultimate sheet temperature 60 to 300 deg.C without washing.
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