Water jet cavitation erosion behaviour of WC reinforced NiCrB composite claddings under varying impingement conditions

Cavitation-induced surface degradation severely limits the service life of stainless-steel components employed in hydraulic and fluid-handling systems because repeated bubble collapse generates localised shock waves and microjets capable of initiating plastic deformation, cracking, and progressive material removal. Therefore, developing a dense and mechanically robust surface layer capable of resisting such repeated impact loading is essential for improving the durability of these components. In the present study, WC + 50%NiCrB composite claddings were developed on SS410 stainless steel using laser cladding and their water-jet cavitation erosion behaviour was investigated under varying impingement conditions. The developed cladding exhibited a dense microstructure with retained spherical WC particles uniformly embedded within the NiCrB matrix and an average thickness of 471 ± 2.39 μm. Elemental mapping confirmed the homogeneous distribution of W, C, Ni, Cr, Fe, and B throughout the cladded region. Localised hardness measurements revealed average hardness values of 582 ± 31 HV for the NiCrB matrix and 2283 ± 76 HV for the WC particles. Water-jet cavitation erosion tests were performed by varying jet velocity (25–35 m/s), impact angle (30–90°), and nozzle-to-specimen distance (4–12 cm). The mass loss increased with increasing jet velocity and impact angle, whereas the maximum erosion was observed at an intermediate nozzle-to-specimen distance of 8 cm. Under all operating conditions, the WC + 50%NiCrB composite cladding exhibited lower material loss than the substrate. The harshest condition corresponded to a jet velocity of 35 m/s, an impact angle of 90°, and a nozzle-to-specimen distance of 8 cm.