Research On Mixed Plasma For Deep Hole Machining Of GH4169 Superalloy

Superalloy GH4169 belongs to a kind of nickel-based superalloy,with high strength and hardness,and the deep hole parts of the material is widely used in aviation,aerospace and other fields,but the deep hole of superalloy GH4169 material has certain difficulty in processing.This paper mainly aims at the problems of serious tool wear,low processing efficiency and high processing cost in the deep hole processing of superalloy GH4169.Based on the theory of mixed plasma discharge high temperature erosion,the mixed plasma deep hole processing method is studied and applied to the deep hole processing of superalloy GH4169.It provides a new technology and method for deep hole processing of this kind of material.Firstly,the feasibility of deep hole machining of GH4169 superalloy was analyzed from the mechanism of mixed plasma removal,and the motion state of charged particles in the process of mixed plasma discharge was explored as well as the principle of the removal of polar surface by charged particles.The main factors affecting the machining efficiency and surface quality of workpiece are the electrode feed speed,electrode rotation speed,electrical parameters and pulse energy.Secondly,according to the theory of mixed plasma discharge removal and the existing test conditions,a mixed plasma deep hole machining system is designed.The design content of the system mainly includes the design of special tool electrode,the performance analysis and selection of pulse power supply and the design of working fluid circulation filtration system.COMSOL simulation analysis software,is adopted to establish the hybrid plasma processing of physical model and a heat transfer model of mixed simulation under different peak current parameters of plasma electron density distribution,the size of the electron temperature and electric potential distribution,get along with the increase of the discharge current,the interelectrode plasma electron temperature rising and distribution more and more focused on the surface of the anode;The electron density will also become larger and closer to the anode surface;The potential of the anode surface is greater than that of the cathode surface,and the potential difference between the two poles is the discharge voltage of the pulse power supply.Finally,using the method of single factor experiment,analysis,peak current,electrode material and electrode feed speed and spindle speed on the machining efficiency and surface quality,establish the orthogonal experiments,through poor analysis and grey relational analysis to calculate the influence of different experimental parameters on the test results of the order and the best parameter values are obtained.The experimental results show that the copper-tungsten alloy electrode has good processing effect,and the optimal experimental parameters combination is obtained: peak current is 25 A,spindle speed is 75rad/min,electrode feed speed is 0.45mm/min.Through the test,it is verified that the machining efficiency and surface quality of the hole processed under this parameter combination is higher.