Effect of microwave exposure time on microstructure and slurry erosion behavior of Ni + 20% Cr7C3 composite clads

Abstract

Abstract The phenomenon of slurry erosion in hydro turbines and its components is a major challenge. Microwave cladding is a potential surface modification technique to mitigate the effects of slurry erosion. Microwave exposure time during cladding could play an important role on the microstructure and performance of the developed clads. In the present work, Ni +\u202f20\u202fwt% Cr7C3 composite clads were developed on CA6NM hydro turbine steel using microwave cladding technique. The effect of microwave exposure time on clad microstructure and its subsequent effect on slurry erosion characteristics were studied. The developed clads were assessed in terms of their microstructure, phase analysis, nanohardness and fracture toughness using various techniques. Slurry erosion characteristics of the developed clad were studied using a slurry jet erosion test rig. The slurry erosion trials were performed at a jet velocity of 40\u202fm/s with an impact angle of 90° for 120\u202fmin. Cumulative weight loss, wear rate and wear mechanisms were assessed to determine the slurry erosion performance of the developed clads.