Microstructure And Wear Resistance Of In-Situ Synthesized WCp/Fe Composite Coating By Argon Arc Cladding

The steel material wear are considered to be an important cause of material loss, the economic loss and fatal accident. Along with the fast development of modern industry, the traditional wear-resisting material cannot satisfy the comprehensive performance of modern industry requirements.Tungsten carbide of particles reinforced iron matrix composite coating material is an effective way to solve this problem.an increasingly. Because of the existence of decomposition, pollution and high cost when adding tungsten carbide directly, it is a new choice to adopt the way of in-situ synthesized tungsten carbide preparation technology.The paper describes a method to fabricate tungsten carbide reinforced iron-based wear-resisting composite coating on Q235steel surface by in situ argon arc cladding technology. In this thesis, the author research the effect of the addition methods of tungsten, the adding amount of (WO3+C), the adding amount of graphite, the granularity of WO3on microstructure, hardness and wear resistance by means of optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), micro hardness tester, rockwell hardness tester, wet sand rubber-type abrasion testing machine.The results show that in situ Tungsten carbides particles reinforced Fe-based composite coating was successfully performed by the way of WO3+C+WF372.When the formula of cladding powder is58%WO3+15%C+27%WF372(mass fraction), the WC grain can be in-situ synthesized, the composite coating has high hardness and good wear resistance, the hardness as high as HRC66.5, the mass loss is just0.0086g, the main wear mechanism is microscopic cutting. There is a excellent bonding between the coating and the Q235steel substrate. The strengthening mechanism of the coating mainly includes the second phase strengthening, solid solution strengthening and fine-grain strengthening.When the molar ratio of WO3and C is4:1, with increase in adding amount of (WO3+C), the volume fraction of the rich tungsten phases increased. When the adding amount of the (WO3+C) mixture powder is80Wt.%, in-situ synthesis of WC particles occurred in the coating, the coating has the highest hardness and the best wear resistance.When the adding amount of WO3fix as58%, with increase in adding amount of C, the volume fraction of tungsten carbide increases firstly and then decreases. and the main shape features, in turn, present mesh shape, word of bones of petals from, bulky, massive, the layer of flake and granular. When graphite content is15%and18%, the WC particle generation obvious sink phenomenon.When the adding content of graphite is15%, the process performance of the coating is the best.When the formula of cladding powder fix as58%WO3+15%C+27%WF372(mass fraction), with decrease of the particle size of WO3, the volume fraction of Tungsten carbide decreases firstly and then increases in the the upper part of the coating,and the main shape features, in turn, present bulk primary WC,Cross petals form primary M6C, Granular or fish bone shape eutectic M6C; the hardness trend is first decreases, second increases, and then decrease; the wear loss trend is first increases, second decrease, and then increases.When WO3is without ball milling, the wear resistance of the composite coating is the best.