Prediction of surface modifications induced by orthogonal cutting of IN718 using uncoated WC-Co and PCBN cutting tools

This work investigates surface integrity modifications induced by orthogonal cutting of Inconel 718, a nickel-based superalloy widely utilized in aerospace, marine, and automotive industries for its exceptional mechanical strength and thermal stability. Due to the challenges associated with machining Inconel 718, a model was developed to understand the subsurface and surface modifications better. A 2D orthogonal cutting model is developed in Abaqus/Explicit FEA software, integrating a constitutive material model that accounts for strain hardening, strain rate, stress triaxiality, Lode angle, and temperature effects. After simulating the cooling process, the machined workpiece model was exported to Abaqus/Standard. The influence of the key machining parameters, including cutting speed, tool edge radius, and uncut chip thickness on plastic strain distribution and the thickness of the plastically deformed layer beneath the machined surface was determined for two different cutting tool materials, uncoated WC-Co and PCBN. The findings show that higher cutting speeds heightened the thickness of the deformed layer, while increased uncut chip thickness and larger tool edge radii increase subsurface deformation. Finally, the choice between WC-Co and PCBN tools influenced not only the magnitude of plastic deformation but also the thickness of the plastically deformed layer.