Study On Dry Sliding Friction And Wear Properties Of TiC Enhanced Ni-based Laser Cladding Wear Resistant Coatings

In this paper,the TiC reinforced nickel-based composite coating was prepared on the surface of 45#steel by laser cladding technology,and the effects of the amount of TiC on the structure and mechanical properties of the coating were studied respectively.On this basis,the effects of the amount of TiC on the dry sliding friction and wear properties of the coating were studied.The results are as follows:Through the design of the laser process parameters,the best process parameters are the laser power of 2000W and the scanning speed of 3mm/s.The main products in the laser cladding process are hard phase M₂₃C₆,M₇C₃,CrB and solid solution?-Ni.The macroscopic hardness values of the laser cladding layers with the TiC content of 0%,15%and 30%were 58.8 HRC,66.3 HRC and 69.9 HRC,respectively.The friction and wear properties of the material include its wear resistance and friction coefficient stability.The average friction coefficient of the laser cladding layer without TiC fluctuates between 0.611 and 0.831.The friction coefficient of the laser cladding layer with TiC content of 15%is the most stable,which fluctuation range is stable from 0.571 to0.633,and the fluctuation range is only 0.062,which effectively improves the friction stability of the laser cladding layer.The wear resistance of laser cladding layer can be improved by adding TiC.Under high load,the laser cladding layer with TiC content of 15%has the lowest wear rate and stable wear resistance.Under lower load,the surface of laser cladding layer with TiC addition is slightly worn.When the load increases,the surface of laser cladding layer with TiC addition of 30%begins to suffer severe delamination wear,while under the same load,the surface of laser cladding layer with TiC addition of 15%is slightly worn.When the load is 120N,micro-cracks appear on the sub-surface of the wear surface of the laser cladding layer with30%TiC addition,which will cause hidden danger to the subsequent wear process.After laser cladding wear,the microhardness of the surface layer of the profile increases significantly.With the increase of load,the thickness of hardness hardening layer of the grinding surface increases to 50um.The hardness of laser cladding coatings annealed at 500?and 900?was 63.2 HRC and 60.5 HRC respectively,which decreases to a certain extent.The stability of friction coefficient of laser cladding layer can be effectively improved by annealing at 500?.The range of variation is only 0.546-0.618.With the increase of the load,the wear resistance of the cladding layer is improved by the heat treatment process.When the load is 120N,the wear rate of the cladding layer material is 1.910×10^-6 g/m,and the wear rate is reduced by30.77%.The cladding material under this heat treatment is mainly slight wear and oxidation wear under low load,and the delamination wear accompanied by oxidation wear under high load can effectively reduce the wear degree of the wear surface.The thickness of the hardened layer increases with the increase of the load.When the load is 120N,the thickness of the hardened layer reaches 50um.