Cavitation erosion of flame spray weld coating of nickel-base alloy powder.pdf

ELSEVIER Wear 189 ( 1995) 2G24 WEAR Cavitation erosion of flame spray weld coating of nickel-base alloy powder Kezheng Sang, Yugang Li Mechanical Engineering Department, Xi’an institute of Highways, Xi’an, China Received 19 October 1994; accepted 26 January 1995 Abstract The cavitation erosion of flame spray weld coating of five kinds of commercial nickel alloy powder was investigated by using a vibratory cavitation apparatus. For comparison a plain carbon steel and a stainless steel were also studied. The result showed that the cavitation erosion resistance of the flame spray weld coating of the nickel alloys was strongly related to the degree of solution hardening of the matrix and the quantity, fineness and dispersivity of the second phase (compound). Keywords: Cavitation erosion; Nickel alloy; Coating 1. Introduction The failure of pipelines, pumps, water-turbine blades and other hydraulic sets can often be attributed to cavitation ero- sion. So the cavitation erosion resistance of some alloys and steels has been widely studied [ l-61. In China, the methods of building up by welding stainless steel rods or flame spray alloy powders are commonly used to repair damaged parts. And nickel alloy powder is a common kind of powder used in flame spray welding. Nowadays there is very little information about the resis- tance of flame spray weld coating to cavitation erosion. A number of cobalt-based stellite alloys have been evaluated for erosion resistance by Heathcock et al. [7]. They sug- gested that the cobalt-rich solid solution is of prime impor- tance in determining the erosion resistance of cobalt-base stellites. But the morphology of carbides, hardness and fine- ness of microstructures determined by the chemical compo- sition also have an influence on erosion resistance. The erosion resistance of two kinds of nickel alloy was studied by Tomlinson et al. [ 81. It was reported that laser processing always substantially increased th