Evaluating the Effect of HVOF Sprayed WC-10Co-4Cr and Hard Chromium Electroplated Coatings on Fatigue Strength of Axle-Shaped Machine Parts

Hard chrome plating technique has been widely used to corrosion-resistant with a thickness of less than 100 mu m without re-processing. However, hard chrome coating always generates the tensile residual stress and microcracks. They reduce the fatigue strength of the machine parts. Nowadays, the HVOF method has been studied as the alternative method for chrome plating. A WC-10Co-4Cr coating layer contains compressive stress and increases mechanical properties of surface details, or in other words, achieves higher fatigue strength. In this study, the influence of coating layers with thicknesses of 30 lm and 60 lm (covered by chrome-plated and HVOF technique) on the fatigue strength of AISI 1045 steel has been investigated. Results of microstructure investigation showed that the residual stress of the coating layer affected fatigue strength. The fatigue strength of tungsten carbide coating is 12.5% higher than those of chrome plating at 30 lm and 17.9% for a thickness of 60 mu m.