Research On Tool Wear And Surface Quality In Precision Cutting Of Nickel-based Super Alloy

Nickel-based super alloy GH4169 with excellent heat resistance has been widely used in the manufacture of heat resistant parts of aerospace engine. However, it has the characteristics of high hardness, high plastic deformation, low thermal conductivity and so on, which makes the tool wear serious and the machined surface quality poor. How to reduce tool wear and improve the surface quality of the machined surface is the key to solve the problem of precision cutting.Tool wear and surface quality of the workpiece can be directly influenced by cutting force and cutting temperature during nickel-based super alloy cutting process. Therefore, in this paper, two-dimensional cutting model simulation study of the cutting process of nickel-based super alloy was conducted by using the finite element simulation software DEFORM, and then the influence of the process parameters and flank wear VB value on cutting force and cutting temperature were analyzed; the precision cutting experiments were carried out, and then the validity of the finite element simulation results was verified by the comparison of the experimental cutting force results and the simulation ones.The experiments of cutting tool wear in precision cutting nickel-based super alloy with PCBN cutting tool were carried out, the micro morphology of tool wear area was detected by SEM, and then combined it with wear morphology, chip morphology and EDS analysis results to obtain the comprehensive analysis result of the mechanism of tool wear; based on the above, the impact frequency model of chip’s adiabatic shear effect on cutting edge was established; based on the analysis of flank wear width VB, the mathematical prediction model of flank wear VB was established.Experiments were conducted to study the effect of process parameters on the surface roughness, and then the mathematical prediction model of surface roughness Ra was established; the simulation of residual stress on the machined surface in nickel-based super alloy cutting process was carried out, and the influence of cutting parameters and tool geometry parameter on the residual stress of the machined surface was studied; b ased on the optimization of the process parameters with VB value of tool wear and surface roughness Ra as evaluation indexes, the precision cutting experiments of nickel-based super alloy under different cooling and lubrication conditions were carried out, the effect of different cooling methods and different cooling lubricant on tool wear and surface roughness was studied, which provided the theoretical basis for the optimization of precision cutting process conditions of nickel-based super alloy.