Study On Milling Machinability And Process Optimization Of GH4169 Nickel-based Superalloy Under Minimal Quantity Lubrication Condition

In the field of advanced manufacturing at home and abroad,the demand for material properties is increasingly high.GH4169 nickel-based superalloy has excellent high temperature strength,oxidation resistance and corrosion resistance,which can meet some special requirements in high-end manufacturing.Because GH4169 is a typical difficult material to machine,it will produce the situation of large cutting force,serious tool wear and poor workpiece accuracy in the process of machining.In order to improve this phenomenon,it is usually cooled by micro lubrication cooling method.The main research contents of this paper are as follows:(1)Research on the machinability of GH4169 nickel-based superalloy milling under the condition of minimal lubrication was carried out.The influences of cutting speed,radial cutting depth,cutting oil flow rate and compressed air pressure on the surface roughness,milling force and surface hardness of the workpiece were analyzed.The simulation software LAMMPs was used to simulate the milling process under the condition of micro nano fluid lubrication.The results show that there is a negative correlation between cutting speed and workpiece surface roughness,and a positive correlation between tool feed per tooth and workpiece surface roughness.The cutting forces in X,Y and Z directions all decrease with the increase of cutting speed.The feed per tooth,radial cutting depth and cutting speed are positively correlated with the surface microhardness of the workpiece.With the addition of carbon nanotubes,the cooling and lubrication performance of micro lubrication system is improved.(2)The tool wear tests were carried out under dry cutting and trace lubrication conditions.The evolution law of milling force with wear and the type and mechanism of tool wear were analyzed.The results show that the effective milling distance of the tool is 1000 mm,and the wear types of the tool are oxidation wear,abrasive wear and bonding wear.Under the condition of minimal lubrication,the effective milling distance of the tool is 2000 mm,and the tool wear types are diffusion wear,abrasive wear and oxidation wear.(3)Based on the response surface methodology(RSM),the prediction models of the minimum surface roughness and the cutting forces in X and Y directions in the milling of GH4169 nickel-based superalloy under the condition of trace lubrication were established.The significance of each variable,the interaction effect and the prediction model accuracy were discussed by variance analysis.MOPSO algorithm based on crowding distance sorting was used to find the optimal solution for the multi-objective optimization model,and the optimal machining scheme was determined by TOPSIS method.It is found that the feed rate of each tooth,F_z,has the most significant effect on the surface roughness and the cutting force in X and Y directions.The interaction between the feed rate per tooth and the compressed air pressure has the most significant effect on the surface roughness.The interaction of feed rate per tooth and cutting oil flow rate has the greatest influence on the cutting force in X and Y directions.The optimal machining parameters were determined as follows:cutting speed v=63.20 mm/min,feed per tooth f_z=10?m,cutting oil flow Q=0.0309 L/h,compressed air pressure P=3 Bar.The paper has 57 pictures,19 tables,and 85 references.