| abstract |
A multiple coated composite steel strip having an excellent corrosion (rust) resistance, weldability and paint adhesion, and thus useful for car bodies, comprises a steel strip substrate, a first metal coating layer, a second chromate coating layer formed by an electrolytic chromate treatment method, containing 40 to 120 mg/m² of chromium and having a content of Cr₂O₃ of 45% by weight or more, and a third resinous coating layer comprising a homopolymer or copolymer of acrylic acid, methacrylic acid, acrylic acid ester or methacrylic acid ester and 15% to 40% of colloidal silica particles having a very small size of 1 to 12 m µm. |