Research On The Surface Integrity Of High-Speed Milling Of Inconel 718

Nickel-base superalloy Inconel 718 has been widely used in aerospace, petrochemical, automotive and other key industrial areas due to its excellent mechanical properties at high-temperature. Because of their lower thermal conductivity, large friction coefficient and so on, the problems occur in the course of milling such as high cutting temperature, large specific cutting force and serious tool wear, causing their production efficiency influenced, Inconel 718 is considered as difficult-to-machine material. With its wide range of application and the requirements of higher productivity, the surface integrity of high-speed cutting Inconel 718 has become a focus of current research.Along with the developments of the modern high-performance machine and advanced cutting tools, high-speed cutting difficult machining materials have become reality. Through high-speed dry milling technology, the surface quality of Inconel 718 is studied in this thesis. Surface roughness, surface microhardness and surface residual stress are used as the evaluation indicators of surface integrity. The influence of cutting speed on surface integrity is researched.After high-speed face milling Inconel 718, machined surface roughness, micro-hardness and residual stress have been investigated. The results show that, in the selected cutting speed range, the value of surface roughness is getting smaller and smaller with the increasment of cutting speed. Micro-hardness is also getting smaller and smaller. In addition, the machined surface stresses are all tensile residual stresses. With increasing cutting speed, the residual tensile stress decreased, which is beneficial for the fatigue life of the machined part.When side-milling Inconel 718 with coated cemented carbide cutting tools, tool flank wear have a downward trend with increased cutting speed, which indicates that high-speed cutting is in a role of getting long tool life. The surface roughness value at the lower range of cutting speed is smaller, while it is with greater value at higher cutting speed. Cutting speed has little effect on surface hardening. The surface roughness firstly increases with the cutting speeds increasing, then lower volatility.By using FEM software such as ABAQUS, DEFORM-3D and ADVANTEDGE FEM, cutting process of the parts have been simulated. The influences of rake angle and cutting thickness on the cutting force, cutting temperature and residual stress are researched using ABAQUS. Using DEFORM-3D, the face milling processes are simulated. The side milling processes are simulated by ADVANTEDGE FEM. The simulated values of residual stresses ares compared with the experimental results. The results show that the same trend of residual stresses change with cutting speed, which indicated that the FEM model is correct and the finite element simulation method can provide a reference for the experiments to some extent.