HEAVY CORROSION-PROOF COATED STEEL MATERIAL COATED WITH CORROSION-PROOF RESIN LAYER

摘要

PROBLEM TO BE SOLVED: To provide not only substrate treatment excellent in cathodic peel resistance at a high temperature reaching 100 deg.C but also a heavy corrosion-proof coated steel material high in reliability. SOLUTION: As the substrate treatment of a heavy corrosion-proof coating, treatment using a metal powder containing zinc as main component and a chromic acid aqueous solution is applied to a steel material and the treated steel material is baked and dried to form a film layer 2, and a resin primer layer 4 and a corrosion-proof coating layer 5 with a thickness of 0.3 mm or more are successively laminated on the film layer 2. Since an iron exposed part is eliminated by the substrate treatment, corrosive electrolytic reaction is suppressed and cathodic peel resistance at a high temperature can be enhanced and a corrosion-proof coating high in reliability is obtained.