Composite spray-coated member excellent in corrosion resistance and erosion resistance and method for producing the same

摘要

PROBLEM TO BE SOLVED: To improve the resistance to the erosion action caused, e.g. by the dust discharged from a converter and composed essentially of iron oxide and the droplets of molten steel, to improve cooling property, and to prolong the service life of a member. SOLUTION: This composite spray coated member can be produced by forming an undercoat sprayed coating 7 composed of heat resistant metal or its alloy or carbide cermet on the surface of a base material such as pipe to 20-500m thickness, interposing a porous inorganic film 9 if necessary, applying a sealing agent composed essentially of chromic acid and phosphoric acid onto the above, and, after drying, performing heating and baking at 350-550 deg.C for =0.3hr to form a hard vitreous chromium oxide film 8 with a thickness of 0.5-20m, preferably 2-5m, as an upper layer.