MANUFACTURING METHOD OF PHOSPHATE-TREATED STEEL SHEET FOR MIXED MODEL PRODUCTION AND PHOSPHATE-TREATED STEEL SHEET

摘要

The present invention relates to a method for manufacturing a galvanized steel sheet for a mixed production having phosphate treated therein, and a galvanized steel sheet manufactured thereby, having phosphate treated therein. The method of the present invention comprises the steps of: forming a zinc plating layer on a surface of a base steel sheet; and spraying and coating an aqueous solution for treating phosphate with a coating amount of 1.0 to 1.8 g/m^2 at 50 to 60C on the zinc plating layer formed on the surface of the base steel sheet, and drying the same to form a multicomponent phosphate coating layer. The multicomponent phosphate coating layer contains 1,500 to 2,500 ppm of manganese (Mn), 1,400 to 2,500 ppm of zinc (Zn), 1,300 to 2,000 ppm of nickel (Ni), and 20 to 200 ppm of cobalt (Co). Thus, according to the present invention, a zinc plating chip is prevented from being fixed to a mold. In addition, chapping resistance, galling resistance, and adhesion are excellent, and a mixed production of an alloying hot-dip galvanized steel sheet and electro-galvanized steel sheet is possible since a mark of a suction cup is not generated after coating.