| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrogalvanized steel sheet excellent in plating film adhesion and edge face corrosion resistance after coating. SOLUTION: In this method, a steel sheet subjected to pickling treatment is dipped into an electrogalvanizing bath contg. dextrin and/or 0.05 to 10 wt.% dextrin and metallic ions by the quantity sufficient for precipitating 0.01 to 10 wt.% Co, Ni, Cr and Fe in a plating film to form a galvanizing film on at least one side of the steel sheet. The sulfuric acid pickling treatment is executed in such a manner that a pickling soln. in which the concn. of sulfuric acid is regulated to 0.1 to 10% is used, the temp. is regulated to 20 to 70 deg.C, the dipping time is regulated to 1 to 5 sec, and the relative flow velocity is regulated to 1 to 3 m/sec, and it is preferable that, when the range of 1 mm×1 mm in the surface obtd. thereby is observed, the maximum area ratio of etch pits present in the range of 10μm×10μm is regulated 0.1 to 10%.
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