Research On Residual Stress Simulation Of Turning Nickel-based Superalloy In Spray Cooling

Nickel-based superalloy(GH4169)has excellent performance in fatigue resistance,antioxidation and corrosion resistance.It is the mainly used in the manufacture of finishing parts such as turbine engines and wheel discs of gas turbines.However,high cutting temperatures,high cutting forces and severe tool wear during machining of Nickel-based superalloy affect the residual stress of workpiece,which in turn reduces the surface machining accuracy and weakens the corrosion resistance of work piece.The micro-textured tool with biomimetic design and micro-lubrication technology reduce the friction of the tool on workpiece and chips,lower the cutting temperature,and reduce the residual tensile stress on the machined surface.In this paper,the residual stresses of the workpiece when turning Nickel-based superalloy with both non-textured tools and micro-textured tools respectively in spray cooling are studied by simulation with Advant Edge software,and the changes of the residual stresses of the workpiece with different micro-texture parameters are investigated in depth,and the main points of research are as follows:Firstly,the spray velocity at different pressure and flow rate of spray cooling was obtained from the fluid calculation equation;the values of convective heat transfer coefficient at different pressure and flow rate in spray cooling were simulated and analyzed by ANSYS software.The spray velocity and convective heat transfer coefficient were imported into the simulation software to investigate the residual stress of turning Nickel-based superalloy with non-textured tool in spray cooling,and further analyzed the influence of spray parameters,tool parameters and cutting parameters on the variation of residual stress.Secondly,micro-textured tools of five different morphologies on rake face were designed based on the bionic principles,and the tools with designed micro-textures were modeled by UG.The effect of different micro-textures on the residual stress of workpiece in spray cooling was investigated in the rounding turning simulation module of Advant Edge software.The optimal micro-texture morphology of tool was obtained with the objective of minimizing the residual tensile stress on surface.The significant effect of different micro-texture parameters on the residual tensile stress on the surface was subsequently investigated by changing the width of the micro-texture,the rounding angle,the distance from the cutting edge and the spacing of the micro-texture in the selected optimal micro-texture.Furthermore,the designed micro-textured tools were machined and used in cutting experiment.The residual stresses on workpiece in spray-cooling cutting with non-textured tool and micro-textured tools were tested by X-ray diffractometer.The residual stresses at different pressure and flow rate were analyzed to verify the accuracy of the simulation models of the non-textured tool and the micro-textured tools for turning nickel-based superalloys.Finally,taking the micro-texture parameters as the input layer neurons,and the residual stress as the output layer neurons,the BP neural network code was written in MATLAB software to predict the surface residual stress.The prediction of surface residual stress provides a reference for selecting the cutting parameters and micro-texture parameters at the initial cutting stage.