Research On Mechanism Of Micro-cutting Superalloy Inconel 718 Based On MQL

Nickel-based superalloy Inconel 718 has the highest usage of superalloys in aviation,aerospace,transportation,energy and other fields.At the same time,the development of aerospace and other fields has promoted the development of micro-cutting processing.As a difficult-to-machine material,Inconel 718 has always been one of the important topics in metal cutting.Minimum quantity lubrication(MQL),as a new type of cooling lubrication,can effectively reduce the cutting temperature and tool wear during Inconel 718 machining.Ultrasonic elliptical vibration(UEV)cutting is also increasingly used in the machining of Inconel 718,which can effectively reduce cutting forces and cutting stress.Both processing methods have advantages and disadvantages.In this paper,the mechanism of micro-cutting superalloy Inconel 718 is studied in this paper under various conditions such as microlubrication,ultrasonic elliptical vibration and cryogenic minimum quantity lubrication.The main contents of this paper are as follows:First,the Inconel 718 micro-cutting simulation model was established by the finite element software Advant Edge FEM,and the material model and meshing were defined.Then the MQL micro-cutting model was established to study the influence of five parameters(cutting speed,feed rate,depth of cut,cutting edge radius and rake angle)on cutting temperature and cutting force of micro-cutting Inconel 718 under MQL and dry cutting conditions.In the process of micro-cutting,MQL cutting has significantly reduced cutting temperature and cutting force compared to dry cutting.As the cutting speed increases,both the MQL cooling optimization ratio and the cutting force optimization ratio increase.As the tool rake angle increases,the MQL cooling optimization ratio decreases.When the rake angle is greater than 6 °,the optimization ratio of the main cutting force and thrust of MQL will increase as the rake angle increases.Secondly,based on the above parameters,the residual stresses under these two cutting conditions are studied.The smaller the feed amount and the tool nose radius,the shallower the residual stress on the workpiece surface.As the rake angle increases,the MQL residual stress optimization ratio decreases.The Taguchi method was used to analyze the influence parameters of residual stress.According to the signal-to-noise ratio distribution of each factor level,the optimal combination of the contribution of each parameter to the residual stress and the parameter of the minimum residual stress was obtained.Experimental values verify the effectiveness of the Taguchi method and finite element analysis.Finally,the mechanism of multi-condition micro-cutting Inconel 718 for conventional cutting,MQL cutting and UEV cutting is studied.The UEV cutting principle and MQL heat transfer principle are analyzed,and a heat transfer model with different nozzle angles under ultrasonic elliptical vibration cutting conditions is proposed.Compared with conventional cutting,the temperature of elliptical ultrasonic vibration cutting is reduced by 10.8%,the main cutting force and thrust are reduced by 61.5% and 73.9% respectively;the cutting temperature during elliptical ultrasonic vibration and minimum quantity lubrication coupled cutting is reduced by 15.7%,the main cutting force and thrust reductions of 67.6% and 79.4%,respectively;cutting temperature in the coupling of elliptical ultrasonic vibration and cryogenic minimum quantity lubrication reduced by 19.8%,and the main cutting force and thrust reduced by 62.7% and 75.3%,respectively.When the nozzle angle θ changes from 11 ° to 0 °,the temperature of the cutting deformation zone and the tool decreases,and the distribution range of the maximum temperature decreases.The tool stress also decreases with the decrease of the nozzle angle,which improves the machining performance and tool durability.