Composite Of WC Particles Reinforced Iron-based Wear Resistant Cladding

Phenomenon of dissolution of carbides and uneven distribution of carbides was found in carbide reinforced coatings produced by thermal spraying, hardfacing and laser cladding. To resolve these issues, self-made powder back feeding facility was used in fabrication of WC reinforced Fe based composited coating with good-processing. The problem of carbides dissolution was solved effectively and the wear resistance of the coating layer was also improved. The experiment data and analysis would be helpful in both theory and practice of developing powder reinforced coating materials with high-performance.In this paper, We prepared WC particles reinforced Fe-based composite coating on45steel surfaces by using back feeding technique of plasma spray welding. The effect of travel speed of the welding torch on the structure and property of coating layer on case of no swing was studied. The influences of current size, travel speed and the gas flow of back-feeding on the structure and property of coating layer on the case of torch swing were also discussed. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy diffraction spectrum (EDS) were used to examine the microstructure and composition of the coating layer. The wear resistance of coating layer was tested by MMW-1A wear test machine at room temperature condition with lubricating oil. The surface morphology of wear specimens were observed by using SEM. And wear mechanisms of coatings were analyzed.The results showed that the speed of torch walking affecting on the organizational performance of single channel spray cladding is not obvious. When the torch travel speed is80mm/min, the coating has good abrasion resistance and higher microhardness. The organization of different parts of cladding is nearly same. In composite cladding layer are mainly distributed evenly WC particles, Fe, Cr eutectic, bright white carbide particles around WC (WC etc.), organization-like fish bon, thin strips carbide (FeeWgC, Cr?C3, etc.). The overall hardness showed a continuous increasing trend, and much higher than the hardness of the cladding layer substrate. The organizational performance of coating in all continuous spray cladding is best, when the main parameters are130A(welding current size),65mm/min(the torch walking speed),4L/min(the gas flow of back-feeding). the structure of coating mainly included the primary crystal structure of light gray and dark gray structure. The trend of coating section microhardness is gradient distribution, up955.63HVo.2-The wear mechanism of plasma spray WC particles reinforced Fe-based composite coating was mainly abrasive wear, the coating wear resistance was improved obviously. The wear resistance of the coating which prepared by larger or smaller current was poorer. Under oil lubrication conditions, wear resistance of WC particles reinforced Fe-based composite coating is about35times than Crl2MoV.