Parametric Study of Residual Stresses in HVOF Thermally Sprayed WC–12Co Coatings

Abstract

In this paper, the effect of the main process parameters of high-velocity oxygen fuel (HVOF) thermal spraying on the particles characteristics and surface residual stresses of WC–12Co coatings was studied. Taguchi approach was used for design of experiments. Four more effective parameters such as spray distance, oxygen-to-fuel (O/F) ratio, powder feed rate, and gun travel speed were selected as inputs. The sin2ψ method was used to evaluate the surface residual stress by means of X-ray diffraction (XRD) method. Spray Watch diagnostic system, scanning electron microscopy (SEM), and XRD were used for this purpose. The statistical results showed that the spray distance and O/F ratio are the most effective factors on the particle characteristics and residual stresses. The particles velocity and temperature were varied in range of 418.8–449.4 m/s and 1749.2–2055.4°C, respectively. The surface residual stress was in the range of 31.9–84.6 MPa.