1992 Volume 78 Issue 12 Pages 1810-1817
The newly developed organic composite coated sheet steel is as follows. Zn-Ni alloy plated sheet steel with a coating weight of 30 g/m2 and average Ni concentration of 11.5 12.0% is chromated through electrolysis. The coating weight of chromate film is 5090 mg/m2 in Cr.
Furthermore, emulsified olefin-acrylic acid copolymer resin mixed with colloidal silica of particle size 78nm is applied to a thickness of 1.01.8μm. Orefin-acrylic acid copolymer resin and colloidal silica are mixed at the rate of 100 and 30 (parts by weight). The result of mixing the colloidal silica with the resin is that abration resistance of the organic film is remarkably improved and it therefore maintains excellent corrosion resistance and paint adhesion.
The new sheet steel maintains excellent corrosion resistance, including flat plate, even after bead forming and 20% stretch forming and furthermore excellent paint adhesion and cathodic electro deposited paint corrosion resistance. As a result of the combination of the above-mentioned properties, it has excellent perforation resistance. However, it should be used such that the organic film of two peaces of the coated sheet steel make contact with. The product has excellent weldability, too.
