Process adhesion, is superior corrosion-resistant the galvanized sheet iron null for the organic brush revetment steel sheet

摘要

PROBLEM TO BE SOLVED: To provide a galvanized steel plate used for an organic resin coated steel plate, on which particularly a ≥10μm thickness organic coating film is formed through an adhesive, excellent in adhesion after processed, water resistant adhesive property, corrosion resistance at an end face and corrosion resistance at a cross cut part more excellent than that of a phosphate and easily producible. ;SOLUTION: A surface treated steel plate has a zinc or zinc based alloy plated layer and a chemical conversion treated layer formed on a steel plate. In such a case, the chemical conversion treated layer contains 2 kinds of fumed silica each having ≥10nm to ≤14nm and ≥5nm to ≤9nm primary particle diameter and a chromic acid compound, the mixed SiO₂/Cr by weight when the coating weight of the fumed silica is expressed in terms of SiO₂ and the coating weight of the chromic acid compound is expressed in terms of metal chromium is ≥3 to 6 and the coating weight of Cr is ≥25mg/m² to ≤55mg/m².;COPYRIGHT: (C)1998,JPO