Preparation And Properties Of Laser Cladding WC Based On Co

Friction wear is the main failure cause of the parts in mechanical movements.Frequent replacement of the parts consumes materials and wastes manpower,increasing production costs.Laser cladding technology is an effective means to improve the surface test performance of matrix materials.Laser cladding technology is used to prepare Stellite6-Co based cladding layer reinforced by WC particles on the surface of the Q235steel.The cladding layer has good hardness,thermal stability and wear resistance,which enhances the surface properties of the common materials and prolongs the service life of the parts.According to thermodynamic reasons,stellite6-Co based cladding layer reinforced by in-situ autogenic WC particles was designed.Through orthogonal test,analyzing the mean and range of the surface quality and surface hardness to calculate the best process parameters.The microstructure,phase composition,element distribution,microhardness and wear resistance are analyzed by using SEM,XRD,EDS,microhardness tester and friction wear testing machine.The process parameter:laser power,cladding speed and powder feeding speed influence on cladding layer are analyzed.The principle of WC strengthening cladding layer were determined.The optimal process parameters obtained in this topic are:laser power 1800W,cladding speed 5mm·s^-1,powder feeding speed 20g·min^-1.The cladding layer which was made by these technological parameters formed a good metallurgical bonding with the base material and had no obvious defects on the surface.The hardness and wear resistance of the cladding layers were obviously improved compared with the base material.When the heat input was insufficient,the formed cladding layer could not melt and mixed with the new molten pool,resulting in the accumulation of cladding layer.The overall microhardness and wear resistance of WC particles reinforced Co cladding layer are increased by using the best technological parameters.However,when the addition amount of W was 10wt%,part of W particles could not completely in-situ autogenic reaction to generate WC.which fell off during the friction test,resulting in abrasive wear and resulting in reduced wear resistance.The common microstructure phases of cladding layer areγ-Co,CoCx and Cr7C3.WC,W2C and other carbide phases are found in the inner microstructure of cladding layer with directly added WC and in situ self-generated WC,and the grain size of cladding layer with in-situ self-generated WC is obviously smaller than that with directly added WC.By comparing microhardness,wear resistance and microstructure uniformity of cladding layer,the optimal powder ratio is obtained:92wt%Stellite6 powder+6wt%W+2wt%C.It provides detailed data for the preparation of the high-performance cladding layer,and further advances the application of laser cladding technology.Figure 45;Table 7;Reference 54...