| When wear parts works, due to the friction of material, easy to failure because ofthe size of its changes. In order to improve the mechanieal performance of vibrationscreen plate and prolong its operational life. The Argon gas protection resistancefurnace was used in this article with different cladding process (the claddingtemperature1200℃,1230℃,1260℃respectively and the holding time10min,30min,50min respectively), a nickel-based cladding layer reinforced by WC which isabout1~2mm thickness was fabricated on A3steel plate surface; Meanwhile, theoptical microscope (OM), scanning electron microscope (SEM), X-ray diffractometer(XRD), micro-hardness tester, rock hardness tester and wear tester and otherequipment was usied to analyzed the distribution of WC, the microstructure, phasecomposition and combination mode of cladding layer and steel matrix organizationchanged; the cladding layer micro-hardness and rock hardness of cladding layer wastested, while the wear resistance test was carried out and then the wear morphologyobservation was performed by SEM to evaluate the wear resistance property ofcladding layer. Optimization of WC content in the alloy powder of cladding layer andthe cladding process.The results of the present study showed that the specimen was consist of steelmatrix, transition layer and cladding layer after cladding,when the specimens wasroasted by1230℃maximum cladding temperature for10min, the surface ofcladding layer smooth more, transition layer width is150~250um and less WCdecomposition. The content of each element in the transition layer between thecontent of elements in the steel matrix and cladding layer of powder, this suggeststhat each element diffusion in cladding process fully, the steel matrix and claddinglayer is given priority to with metallurgical bonding.The microstructure of cladding layer mainly consisted of binding phase, wolframcarbide and hard phase formed by nickel-based fluxed alloy powder. XRD analysisshows that the binding phase is mainly composed of austenite, which includes Fe0.64 Ni0.36, Ni2.9Cr0.7Fe0.36phase and other phase; wolfram carbide tends to dissolve outto form WC and W2C; hard phase is mainly composed of boron carbide, carboncomposite compounds and other phase composition, nd the carbide tends to dissolveout to form M23C6and M7C3respectively. The microstructure of steel matrix thatclosed transition layer is given priority to with pearlite.With increasing of WC content, rock hardness of cladding layer ascend; thesamples containing35.%WC presented the best rock hardness of47.3HRC, morethan three times that of steel matrix rock hardness, about25%higher than65Mn. Themicro-hardness of binding phase and wolfram carbide in cladding layer was654.9HV,and1695.3HV respectively.With increasing of WC content, the wear rate showed a fluctuation and thesamples containing35%WC presented the best wear resistance with0.08mg/m,which is about5times than the wear resistance of steel matrix and is four timeshigher than65Mn. There is a minute quantity and shallow depth of furrows in thewear morphology of the specimen, meanwhile, the quantity of wolfram carbide andother hard particle flaking is little.In conclusion, the surface of cladding layer smooth more, the steel matrix andcladding layer is given priority to with metallurgical bonding, the microstructure ofcladding layer mainly consisted of binding phase, wolfram carbide and hard phaseformed by nickel-based fluxed alloy powder,where the distribution of wolframcarbide is well-proportioned in cladding layer with35%WC content in cladding layeralloy powder after roasted by1230℃cladding temperature for10min,thespecimens represents excellent combination of microstructure. Under this condition,;its rock hardness reached47.3HRC which is about25%higher than65Mn, and wearrate reached0.08mg/m which is four times higher than65Mn. This technology canbe widely used in wear parts surface modification and repaired. |
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