Manufacturing Technique And Properties Of Wear Resistant Particle Reinforced Composite Coatings By Argon Arc Cladding

WC-steel composite materials are widely used in cutting tools, metal working tools with non-filings, wear-resisting constructural parts, and dies, because of their widespread craft characteristic, good physical and machinical properties and outstanding chemical stability. Composite wear-resistant coatings reinforced by WC particles were coated on the 45 steel's surface by means of modified arc spray technique, remelted by argon shielded arc remelting, and heat treated properly. The microstructure, phase compositions and wore surface of the composite coating was investigated by means of metallographic microscope, scanning electron microscopy(SEM), X-ray diffraction(XRD), and energy dispersive spectroscopy(EDS). The microhardness of composite coatings was measured by the microhardness tester. The wear resistance of the composite coating sliding against 45~# steel was valuated using an MM-200 test rig in a ring-on-block configuration under unlubricated condition. Wear characteristics and mechanism of composite wear-resisting coatings were discussed in this paper.The results indicate that the microstructure of composite coatings after argon shielded arc remelted are more homogeneous and thinner than WC-steel composite coatings after arc sprayed. There is a good hardness gradient layer in the vicinity of coating matrix and interface. The composite coatings are mechanically bonded to the substrate after arc spraying, but metallurgically bonded after argon shielded arc remelting. The wear volume losses of cladding containing 40wt%WC are more than that of cladding containing 35wt%WC, but less than the cladding containing 25wt%WC or 15wt%WC. The dominant wear mechanism of cladding with 40wt%WC is slight spalling and cutting. Its spalling is heavier than that of the cladding containing 35wt%WC, and lighter than that of the cladding containing 25wt%WC or 15wt%WC. The cladding with 35wt%WC has better wear resistance than the others, whose wear mechanism is slight cutting and spalling. The dominant wear mechanism is slight spalling and heavy cutting for the clad with 25wt%WC content, adhesion and slight cutting for that with 15wt%WC content.