SEDIMENT EROSION ON LASER-CLAD SURFACE FOR HYDROPOWER APPLICATIONS

Abstract

Laser cladding is the process of deposition of one material over another material to improve the properties and characteristics of the substrate material. This method improves the erosion behaviour of the materials by changing the surface properties. In the present work, the CA6NM (ASTM743 or 13/4 martensitic stainless steel) surface has been laser clad with Tungsten Carbide (WC) 90%wt and Nickel (Ni) 10% wt. The size of the cladding powder used in this work is 45-106 mm. The erosion behaviour and wear behaviour of the surface is investigated to get an erosion-free surface which is useful for the designing and manufacturing of hydropower components. The optimum parameters that are used for laser cladding are 700W power of 2 kW fiber laser power having a laser beam diameter of 2 mm, scanning speed of 700 mm/min, powder feed rate of 13.5 g/min, and overlapping of 50%. The hardness on the laser-clad surfaces is observed in the range of 650-2630HV. The characteristics of laser-cladded material have been analyzed using the SEM and EDS. The sediment erosion tests on high-speed slurry pot tester have been performed at different affecting parameters like orientation angle from 15° to 90°, velocity from 18 m/s to 31 m/s, and solid concentration from 9000-12000 ppm. It is observed that the erosion rate increases with an increase in orientation angle and the maximum erosion rate occurs at 60° which decreases with a further increase in orientation angle. It is also observed that the erosion rate increases with an increase in the velocity and solid concentration. The erosion wear of CA6NM is decreased with the laser cladding on the surface.