METALLIC COATING FOR BOILER COMPONENTS, USED AS PREVENTIVE AND CORRECTIVE TECHNIQUE, AGAINST CORROSION AT HIGH TEMPERATURES CAUSED BY VANADIUM SALTS.

摘要

Disclosed is a process for rehabilitating and protecting metallic components of boilers exposed to deposits or slags rich in vanadium and combustion gases at high temperatures. These components are normally water walls and superheater and reheater pipes. The process consists in the deposition of a nickel-base metallic coating with a chromium content of from about 40% to about 50% by weight, with a thickness approximately of 500 micrometers and applied by the thermal projection process by electric arc of high production, so as to use the beneficial properties of the proposed alloy of Ni-Cr, and preserve the mechanical properties of the substrate, also performing the superficial modification of the components in the same place where the boiler is located or in the workshop. The coating provides the following characteristics to the components: a) provides a higher chemical stability during the operation of the same; b) inhibits corrosion; c) enlarges the useful life of the same and d) av oids the need of being partially or totally replaced when failed due to damages caused by high temperature corrosion.