Resistência à cavitação do revestimento de carbeto de tungstênio refundido via laser de CO2 aplicado em aço AISI 1020

Abstract

Mechanical engineering is concerned with cavitation as well as the abrasion of sediments carried by the fluid in hydraulic installations, pumps and turbines, mainly due to the damages that these phenomena can cause in the elevators and hydroelectric plants. Proposals for the elimination or reduction of this problem are studied, from the redesign of the component and its installation, to the application of surface coatings with high technology materials. The main objective of this work is tribological analysis of cavitation in AISI 1020 steel samples, coated by termal spraying with Tungsten Carbide and later irradiated by CO2 Laser. The samples were analyzed by SEM/EDS, Optical Microscopy, Rugosimeter, Vickers Microindentation hardness and cavitation resistance. The results were a metallurgical bond between coating and substrate, in addition to densification and surface hardening of the coating due to CO2 laser remelting; The EDS analysis of the substrate and its coating shows the evaporation of more volatile elements such as Chromium and Cobalt at the time of Laser irradiation, and confirms the diffusion of chemical elements of the coating on the substrate; There is a decrease in surface roughness after termal spraying coating. The cavitation test, shows that samples are resistant to erosion cavitation, proof to be superior to commercial materials.