Study On Surface Residual Stress Of Coated Tool In High-speed Self-organizing Cutting Process

Iron-based superalloy GH2132 is widely used in many fields,which is widely used in many fields.Such as aero turbine engine casing,pressure plate,turbine outer ring,etc.But in high-speed machining,because of its large plasticity,high toughness,work hardening serious.Problems such as fast tool wear rate and unstable machining quality exist in the cutting process.It is found that a self-organizing structure can be formed on the surface of the tool under certain cutting conditions.The self-organizing structure can improve the cutting performance of the tool,delay the tool wear rate and prolong the service time.It is also found that the residual stress increases after micro sandblasting.Residual stress can promote the formation of a self-organizing structure.Aiming at the processing problem of superalloy GH2132.AlTiN and TiN/TiAlN coating tools are used to carry out high-speed cutting tests.The relationship between surface self-organization and residual stress of coated tool is established.By coating the surface of the tool micro-sandblasting treatment.Realize the reasonable control of its surface stress,and improve the tool surface performance.It can achieve high efficiency and high-quality cutting of superalloy GH2132.Firstly,the surface self-organization structure characteristics and existing conditions of the coated tool are studied.The high-temperature alloy GH2132 in the processing process.The tool has some problems such as severe wear and short service life.To solve this problem,a milling test is carried out.The study found that in a specific cutting environment.The coating tool produces a wear-resistant,self-lubricating oxide film layer(self-organizing structure)at the stable wear stage.The experimental results show that the conditions for the stable existence of self-organizing structure of Ti Al N coated tool are:F_x=90?110N,F_y=110?170N,F_z=400?510N,?_s=-730?-880MPa;the conditions for the stable existence of self-organizing structure of TiN/TiAlN coated tool are:F_x=140?190N,F_y=160?210N,F_z=180?310N,?_s=-640?-690MPa.The cutting conditions suitable for self-organizing structure generation are as follows:a_p=0.2?0.4mm,a_e=2?4mm,f_z=0.04?0.08mm/z,v_c=60?120m/min.Secondly,The influence of micro sandblasting jet simulation on the surface stress distribution of coated tool is studied.The velocity field and pressure field in the area of the outflow field are analyzed.With the increase of axial distance,the pressure and velocity of efflux in the flow field tend to decrease.When the jet comes into contact with the target surface,the velocity decreases sharply to zero.The pressure on the target surface is symmetrically distributed from center to edge.The radial pressure of the target surface presents a normal distribution curve.The pressure on the target surface presents a downward trend from the center to both sides.When the spray strikes the surface of the coated tool.The pressure and shear forces are studied.This study is prepared for the subsequent micro sandblasting experiment.Thirdly,the influence of micro sandblasting treatment on surface morphology,roughness,and residual stress of coated tool is studied.Al₂O₃ and Zr O₂ are selected.The micro sandblasting test is carried out for AlTiN and TiN/TiAlN coated tools.The objective is to study the effect of micro sandblasting on the surface morphology,roughness,and residual stress of the coating tool.The research shows that if the blasting time is too long or the pressure is too high,part of the tool coating will be eroded.It increases the surface roughness and affects the tool surface performance.When sandblasting parameters are P=0.2-0.3MPa,T=3-5s.Coated tools can obtain smaller surface roughness and larger residual compressive stress.The surface performance of the tool is significantly improved.Finally,The influence of surface residual stress on cutting performance of the coated tool is studied.A single factor test method is used to carry out the test.Cutting tests are carried out for the two coated tools after sandblasting.The influences of residual stress on the surface of the coated tool,cutting force,cutting temperature,tool life,and machining surface integrity are analyzed.The results show that the reasonable residual stress on the coating surface can significantly improve the tool life and reduce the surface roughness.Through the above study,it is found that AlTiN and TiN/TiAlN coated tools can generate a self-organizing structure in the stable wear stage.The structure can play the role of self-lubrication and self-repair.The self-organizing structure can be promoted by proper sandblasting on the surface of the tool.Also,the coated tools treated by micro-sandblasting can effectively reduce the friction between cutter-chip and cutter-work.Because the tool wear is reduced,the service time of the tool is prolonged effectively,and the surface quality is improved.It has guiding significance for surface treatment and green intelligent manufacturing of coating tools.It has a certain reference value to improve the surface quality of superalloy materials.