Treating the organicity brush revetment phosphorus acid chloride treatment spelter plated steel sheet and its

摘要

PROBLEM TO BE SOLVED: To provide an organic resin-coated phosphate treated galvanized steel sheet having corrosion resistance and blackening resistance higher than those of the conventional corrosion protective coated steel, and in which the adhesion of an organic resin film upon the deformation of the steel sheet is excellent, and to provide its production method.;SOLUTION: A galvanized steel sheet is treated with a phosphate treatment liquid comprising Zn²⁺: 2.0 to 5.0 g/L and Mg²⁺: 2.0 to 5.0 g/L, and in which the ratio of the Mg²⁺ density to the Zn²⁺, Mg²⁺/Zn²⁺ lies in the range of 0.4 to 2.5, and the ratio of free acidity to the total acidity in the treatment liquid is 0.020 to 0.15, thus a phosphate film comprising 0.2 to 2.0 mass% Mg and a coating weight of 0.2 to 1.0 g/m² is formed on the surface of the galvanized steel sheet, and further, an organic resin film is formed thereon.;COPYRIGHT: (C)2008,JPO&INPIT