Microstructure And Wear Resistance Of In-situ Synthesized Wcp Reinforced Coating Fabricated By Argon Arc Cladding

The in situ metal matrix composites that possess desirable mechanical properties including high specific strength, good wettability and bonding strength with substrate have attracted a lot of attention. In this paper, the wear resistant coating is prepared on Q235 steel by argon arc cladding with the ferro-tungsten powder as the tungsten source and the graphite as the carbon source. The effect of C/W ratio, Si, Mn, and WC powder and pre-sintering process on the microstructure and properties is investigated through optical microscopy, SEM, XRD, macro-hardness tester, micro-hardness tester and MLS-23 wet sand rubber wheel tester.The results show that:(1) When C/W ratio is less than 1:1, the carbides mainly are composed of Fe3W3 C and the WC particles are hardly found in the coating. When the C/W ratio is 1.25:1, a small amount of WC begins to produce in the coating. When the C/W ratio is 1.5:1, the content of WC increases and the WC particles uniformly distribute. Therefore, the wear resistance is very good.(2) The effect of Si on microstructures and properties of in situ WCp reinforced coating is very obvious. The gathering tendency of carbon atoms increases with the increasing of the silicon content, resulting in forming multiple carbon-rich areas to increase the nucleation ratio of the WC crystal. When silicon content is 5 wt.%, the relative wear resistance is 58 times than that of the substrate, which is corresponding to WC particles distributing uniformly in the coating. The effect of Mn on microstructures and properties of in situ WCp reinforced coating is not obvious while the effect of Mn on properties of the coating is obvious. With the increasing of Mn content, the hardness increases and the wear resistance of the coating increases firstly and declines at last.(3) The addition of WC powder can effectively promote the nucleation of in situ synthesized WC. When addition of WC powder is 5 wt.%, the wear resistance of the coating is excellent, which is corresponding to WC particles distributing uniformly in the coating. There is a lot of graphite on ferrotungsten after pre-sintering, resulting in multiple carbon-rich areas. The wear resistance increases significantly which is corresponding to a large number of WC particles distributing uniformly in the middle-upper area of the coating.