Study On Formation And Deformation Characterization Of Chip In Machining Of GH4169 With PCBN Tool Under High-pressure Cooling

Nickel-based superalloy is widely used in aviation,aerospace and other fields because of its excellent microstructure stability and high mechanical properties under high temperature conditions.However,high temperature alloy is a typical difficult to machine material.Its cutting performance is poor,cutting deformation is large,chip is not easy to break,tool wear and so on,which seriously affect the quality and efficiency of machining.It is an important way to improve the machinability of difficult-to-machine materials by using advanced cutting tools and coolant lubrication technology.PCBN tools have a great potential in difficult-to-machine materials.Therefore,in this paper,the formation and deformation characterization of chip in machining of GH4169 with PCBN tool under high-pressure cooling was studied as follows:First of all,the cause of chip plastic side flow phenomenon of superalloy and its influence weree analyzed.Based on the theory of adiabatic shearing,the forming process of zigzag chips and the deformation characterization were studied.Considering the technical characteristics of high-pressure cooling lubrication,the chip crimp fracture model under high-pressure cooling conditions was established using the theory of cutting bending moment.Cutting bending moment was analyzed by theoretical calculation.Chip breaking boundary of high pressure cooling was predicted based on the criterion of chip breaking under conventional cutting conditions.It provides a theoretical basis for the discussion of chip formation under high pressure cooling.Secondly,Third Wave Advant Edge finite element simulation software was used to establish the simulation model of high temperature alloy cutting under high pressure cooling.The chip formation process of superalloy under high pressure cooling was discussed.The effect of the cooling pressure and the cutting edge parameters of PCBN tool on the chip-breaking,the cutting force and the plastic deformation were analyzed.It provides a technical reference for the cutting test of superalloy under high pressure cooling.Thirdly,the minimum surface roughness was used as the optimization index,and the cutting parameters were optimized through the orthogonal experiment of cutting GH4169 with PCBN tool under high-pressure cooling.The single factor test was carried out based on the optimization results and the machinability of GH4169 superalloy under high pressure cooling was explored.The effects of cutting parameters,cooling pressure and cutting edge parameters of PCBN tool on cutting force,surface roughness and chip macro morphology were analyzed.Finally,the chips of the single factor test were collected and prepared to be specimens and polished.Chip curling radii of high-pressure cooling were studied and the models of chip curl breaking and chip breaking limits under high-pressure cooling were verified.The effects of cutting amount,cooling pressure and cutting edge parameters of tool on the chip plastic side flow were analyzed.Deformation characterization of serrated chip of superalloy under high-pressure cooling was discussed.It provides a theoretical basis for chip control of superalloy cutting under high pressure cooling.