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

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 sin(2)psi 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 degrees C, respectively. The surface residual stress was in the range of 31.9-84.6 MPa.