Turning of Superalloy- A Numerical Modelling

Abstract

Superalloys are widely used in the field of aerospace and automobile industries due to their high strength at elevated temperature, toughness, oxidation and corrosion resistance. But it is difficult to machine since their thermal conductivity and diffusivity are low leading to generation of high temperature at cutting edges. The conventional turning (CT) process has been found to be very challenging task to machine Inconel 718. Therefore, there is a need for an alternative machining method to process it and ultrasonic assisted turning (UAT) is one of the recent methods to machine Inconel 718. The current work is focused on the determination of the cutting forces, material removal rate (MRR) and surface finish (SR) of Inconel 718 workpiece. To achieve this objective, 3-Dimensional numerical model for ultrasonic assisted turning and conventional turning using Lagrangian approach are developed in DEFORM 3D software. The results thus obtained using UAT are compared with CT. A high frequency vibration of 20 kHz having varying amplitude is superimposed onto the cutting tool in the tangential direction. It is found that ultrasonic vibration results in higher MRR and turning produces a superior surface finish compared to conventional turning of Inconel 718. It is also observed that cutting forces decrease during UAT as compared to CT.