Simulations And Experimental Study On Ultrasonically Assisted Turning Of Inconel 718

Inconel 718 superalloy has been widely used in the aerospace, petroleum and nuclear energy industries because of its excellent mechanical properties over an extreme temperature range(from-250°C to 700°C). Unfortunately, these properties, which include high fatigue strength, good corrosion resistance and strong creep resistance, are compromised by strong work hardening, high temperature tensile strength and shear strength, which shorten the tool life and cause severe work-surface damage during conventional machining. To improve the machinability of Inconel 718, ultrasonic vibration assisted technique were applied in cutting process. This paper on Inconel 718, adapting theoretical analysis, finite element modeling and experimental study together, studies effect law of the amplitude and cutting parameter on cutting force, surface quality and tool wear during ultrasonic elliptical vibration turning.A finite element simulation model for ultrasonic elliptical vibration turning of Inconel 718 was developed by the simulation of metal cutting software of AdvantEdge. The simulated average cutting force was compared with the experimental data under the same cutting parameters and good agreement between them was achieved. Based on Taguchi method and finite element method, the significant interactions between five parameters(depth of cutting, feed rate, cutting speed, vibration frequency and amplitude) for the main cutting force obtained from partial-factor design tests, it draws the influence of the cutting parameters such as depth of cut, feed rate, cutting speed, vibration frequency and vibration amplitude on the main cutting force is studied. Optimization of these five parameters in ultrasonic elliptical vibration turning of Inconel 718 for reduce the main cutting force based on the signal to noise ratio distribution of each control factor at each level. Finally, verification tests were carried out to compare the predicted values of the main cutting force with their simulated values in order to confirm the effectiveness of the Taguchi optimization.By combining the theoretical analysis and the experimental study, it comes up with a calculation formula to the height of residue for the Inconel 718 workpiece on ultrasonic elliptical vibration turning on the base plane, and then carrying out the experimental verification. It studies the effect law of the ultrasonic power on the amplitude and the cutting force from Inconel 718 ultrasound elliptical vibration turning on the base plane, and analyzes the condition of tool wear in the different cutting time through scanning and taking photo by using the electron and laser microscope. By studying the processed surface and the cuttings feature, it also explains the formation mechanism of the cuttings surface, the micro cutting conglutination of the workpiece surface and the built-up edge conglutination of the cutting tool, and analyzes the auxiliary cutting effect of the ultrasonic vibration by comparing the tool wear appearance between the general turning and the ultrasonic vibration turning on the base plane under the same cutting situation.