Finite Element Simulation of Machining of Inconel 825, a Nickel Based Superalloy

Abstract

Machining of nickel based super-alloys has gained a lot of importance in the last decade or so owing to their applications in areas like power generation (gas turbine), military aircrafts, marine propulsion and nuclear reactors. However, during high speed machining it faces a lot of problems in regard to thermal stress, and strain hardening, leading to premature tool failure. Use of cooling lubricants has declined in popularity because they pose a lot of problem with regards to their disposal, reuse and environmental safety. As a result coated tools have come into picture which improve the tool life in case of dry machining and increase productivity owing to their high thermal stability and integrity. Inconel 825 is a relatively newer grade of nickel bases super-alloys, on which a few tests have only been done. An attempt has been made to study the temperature and stress behaviour of tool insert, which in this case is taken as SNMG 120408 with respect to turning operation performed on Inconel 825 superalloy. The tool tip temperatures were found out and the temperature profiles were plotted for various feed and cutting speeds. Initial principal stress induced on the tool is also calculated. The variation of tool tip temperature and effective stress with respect to different cutting conditions were analysed and justified with respect to known knowledge. Comparative study has also been made between the uncoated tool and a CVD coated tool for the same cutting conditions.