Effect of WC on Microstructure and Wear Resistance of Fe-Based Coating Fabricated by Laser Cladding

Abstract

As the core component of the wind turbine transmission chain, the wind power gear plays a vital role in the safe and efficient operation of the whole machine. Wind power gears are subjected to varying degrees of wear on their contact surfaces due to alternating load impacts. For wind power gear repair and remanufacturing, laser cladding technology is proposed on the wind power gearbospline shaft. The effect of tungsten carbide (WC) addition on the laser-clad Fe-based coatings was investigated in this study. The morphology and composition of the composite coatings formed with different proportions of WC were studied using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The microhardness and wear resistance were measured with a digital microhardness tester and a wear testing machine, respectively. The coatings were compact with no apparent cracks or pores and the microstructures of the regions above the fusion zone gradually changed from planar crystal to columnar crystal and cellular crystal, while the middle and upper parts of the coating mainly consisted of equiaxed crystals. The microhardness of the coatings gradually increased with the increase of WC content. The coating with 16% WC addition reached a maximum microhardness of 826.2 HV. The increase of WC content improved the wear resistance of the laser-clad Fe-based composite coatings. The wear mechanism of the coatings was mainly abrasive wear, along with slight adhesion wear and oxidative wear.