This paper presents a study of the residual stress and microstructural properties of thick, spray-formed components, produced using the High Velocity Oxy-Fuel (HVOF) thermal spraying process. The forming material used is Tungsten carbide cobalt (WC-Co), a material which is more usually processed using expensive press and sinter technology. The aim of this study is to examine the effect of production parameters on the formation of thick components. In order to fabricate thick specimens, certain problems have to be overcome. More specifically these problems include the minimizing residual stresses, which cause shape distortion in the components and maining the integrity of the coating on a microstructural scale. The dependence of residual stress, and sprayed material characteristics on spraying distance, and powder feed rate conditions is presented. Results show that cylindrical WC-Co components up to a thickness of 9mm can successfully be produced, by careful control of these parameters. This represents a significant improvement on maximum thickness values previously reported for WC-Co [1,2].

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