Influence of tool wear on machining surface integrity of GH4169

Surface integrity is an important parameter to evaluate the machining quality of mechanical parts,and it has a direct impact on the service performance of mechanical parts(including corrosion resistance,wear resistance and fatigue performance). In view of the poor surface integrity when high-speed machining superalloys(also known as heat resistant superalloys),high-speed machining experiments of superalloy GH4169 were carried out to study the influence of tool wear on the surface integrity (including surface roughness,microhardness,residual stress,and microstructure) of high-speed machining superalloy GH4169,improve the surface integrity of superalloys,and provide theoretical support for high-quality machining of superalloys in the future. The experimental results show that the surface roughness R_a reaches the minimum value(0.26 μm) when the flank wear is 0.1 mm. When the flank wear ranges from 0 to 0.3 mm,the average surface microhardness obtained by high-speed cutting superalloy GH4169 is 462HV-551HV,the average surface residual stress is -1 132--651 MPa. The thickness of plastic deformation layer is positively related to the tool wear. When the cutting parameters are cutting speed of 75 m/min,feed rate of 0.1 mm/r,and cutting depth of 0.5 mm,the thickness of plastic deformation layer is 18-56 μm when the tool wear ranges from 0 to 0.3 mm. In general,the surface microhardness and compressive residual stress increase with the increase of tool wear. The surface roughness decreases first and then increases with the increase of tool wear. Excessive tool wear causes poor processing quality. Appropriate tool wear can obtain better surface roughness and surface quality. It is necessary to improve the surface integrity of superalloy GH4169 by controlling tool wear.