| 摘要 |
PROBLEM TO BE SOLVED: To provide a chromium based coated steel sheet which has corrosion resistance in a bent part as well as adhesion to a coating film after coating by treating a coating plating original sheet with a surface control solution containing Mg ions, and substitutionally precipitating Mg over the surface of the plated layer. SOLUTION: A coating original sheet consisting of a hot dip galvanized steel sheet, a hot dip Zn-Al based plated steel sheet, or a hot dip Zn-Al-Mg based plated steel sheet is treated with an aqueous, acidic solution containing 10 to 10,000 ppm Mg ions as well as Ni ions to control its surface, and an Mg compound in 0.1 to 100 mg/m<SP>2</SP>by coating weight expressed in terms of Mg is substitutionally precipitated over the surface of the plated layer. After that, the steel sheet is subjected to chromate treatment so as to be coated with a coating type chromate treatment solution, and, after that, the steel sheet is coated with a resin. COPYRIGHT: (C)2003,JPO
|
