WHITE CHROMATE TREATMENT METHOD IMPARTING EXCELLENT CORROSION RESISTANCE, FINGERPRINT RESISTANCE AND WELDABILITY AND STEEL SHEET SUBJECTED TO THE WHITE CHROMATE TREATMENT

摘要

PROBLEM TO BE SOLVED: To provide a chromate treatment method capable of forming a white chromate film simultaneously satisfying corrosion resistance, fingerprint resistance and weldability on the surface of galvanized steel, and to provide a steel sheet subjected to the treatment.;SOLUTION: In the white chromate treatment method imparting excellent corrosion resistance, fingerprint resistance and weldability, the surface of galvanized steel is coated with a chromate treatment aqueous solution containing a chromic acid compound in which the chromium reduction ratio (Cr³⁺/Cr³⁺+Cr⁶⁺) is 50 to 60% by 9 to 12 g/L, silica by 13/2 to 7/1 expressed in terms of SiO₂/the total chromium content (weight ratio), and phosphoric acid by 16 to 24 g/L, so as to be heated and dried.;COPYRIGHT: (C)2006,JPO&NCIPI