Influence of laser cladding parameters on slurry erosion performance of NiCrSiBC + 50WC claddings

Abstract

Various components employed in hydro machines are rigorously affected by the presence of sand particles throughout their operation which leads to degradation of the target surface. To counteract this menace, laser cladding has been emerged as a prominent technique to produce dense coatings along with enhanced surface properties like hardness and wear resistance. Therefore, in this study, hard layers of NiCrSiBC + 50WC powder were deposited on SS410 steel by laser cladding. Further, the effect of laser beam power, scanning speed, and powder feed rate on quality of clads was investigated. The laser cladded samples were examined for their micro structural characteristics, micro-hardness, and slurry erosion. Performance of NiCrSiBC + 50WC coatings under slurry erosion was evaluated for harsh conditions of various factors namely sand particle size, slurry concentration, impingement velocity, and impingement angle. Laser cladding parameters namely scanning speed and laser beam power were found to have a significant influence on micro-hardness of developed clads, while powder feed rate did not exhibit a significant effect on micro-hardness variations. Owing to higher hardness of deposited materials, slurry erosion resistance of NiCrSiBC + 50WC clad surfaces was greatly enhanced as that of uncoated SS410 steel. From SEM images, plastic deformation, micro-cutting, crater formation, and ploughing were observed as the major wear mechanisms for the slurry eroded clads. Further, from the obtained results, it has been noticed that a blend of high scanning speed, high laser beam power, and intermediate powder feed rate is suitable to develop coatings having superior wear resistance.