Study On Extrusion Die Failure Surface Laser Cladding Repairing Process

Using proper methods to repair or remanufacture molds in service or in the manufacturing process can not only prolong the service life of molds,reduce the cost of enterprises,but also avoid waste of resources.In this paper,Fe-based cladding layer and TiC-enhanced Fe-based cladding layer were prepared on W6Mo5Cr4V2 tool steel by laser cladding technique,and the laser power,scanning speed,overlap ratio and ceramic content were studied by controlling single variable test scheme.Based on the archard wear model,using Deform-3D software to analyze the effect of microstructure on the microstructure,mechanical properties,microstructural morphology,phase composition and mechanical properties of the cladding layer in the cold extrusion of automobile universal joints.The stress and strain of the parts and the wear of the punch are simulated and analyzed,and the results of the simulation are used to repair the actual punch parts.With the increase of laser power,the geometrical parameters(width,melting depth and dilution)of the Fe-based cladding layer increase,the microstructure of cladding layer changes from dendritic to coarse dendrite,and the crystal growth direction And the XRD diffraction peak became stronger and stronger.The main phases were ?-Fe and FeNi.With the increase of scanning speed,the geometrical parameters of Fe-based cladding layer become smaller,the microstructure of cladding layer changes from coarse dendrite to fine dendrite,the crystal orientation becomes worse,the diffraction peak of XRD Less weak.The mean microhardness of Fe-based coating is 1.5 times that of substrate(550HV0.2),and the average hardness value decreases with the increase of laser power and increases and then decreases with the increase of scanning speed.Compared to 15% and 45%,30% of the overlap rate of large area laser cladding effect is better.TiC reinforced Fe-based cladding layer mainly consists of network structure ofNiCrFe,solid solution of Cr,Ni,Ti,C of ?-Fe gray structure and dispersed in the interdendritic TiC particles,and with the TiC content,The forming property of the cladding layer is deteriorated,the internal dendrite continuity is decreased and the texture tends to be broken.With the increase of TiC content,the average hardness of the cladding layer increases due to the fine grain strengthening and the dispersion strengthening of the ceramic particles.The wear resistance of the cladding layer becomes stronger with the increase of TiC content,and the wear mechanism changes from adhesive wear to abrasive wear.Based on Deform-3D software,the numerical simulation results show that the most serious part of the punch in the extrusion forming process appears on the edge of the punch face,reaching 1.5 × 10-5mm,the punch work The wear on the side of the face side is the second,while the other parts do not have more abrasion,which is consistent with the wear of the punch in the actual production.The Fe-based alloy powder was pre-fabricated at the failure site of the punch by laser cladding with laser power P = 3kW,scan rate V = 9mm/s,overlap rate ? = 30% after processing,the results show that mold repair effect is good,laser cladding repair failure mold has a high feasibility.