Comparative assessment of machining induced hardening in HSM of Inconel 718 with aid of eco-friendly cutting fluids

Abstract

Fulfilling the dual demand of better quality along with higher productivity, and further incorporating cleaner manufacturing processes so as to comply with governmental pollution control norms, have been subjecting manufacturers to intense pressure over the globe in recent times. In context of the same, present paper introspects the resulting surface integrity of the exotic superalloy Inconel 718 during high-speed turning under dry, water vapour, and chilled air being the eco-friendly machining environments by employing coated carbide tools at ideal process parameter settings. Furthermore, a focus has been placed on analyzing the effectiveness of cutting fluid supply techniques on to the machining zone using both traditional exterior nozzle and internally through tooling. Assessment of surface integrity was carried out in terms of machining induced hardening through degree of work hardening and nano-hardness variations beneath machined surface. Results showcased beneficial higher degree of work hardening for water vapour and chilled air as cutting fluids, with the prior having a more pronounced effect. Further the supply of cutting fluid through tool holder was advantageous in obtaining machined surfaces that are considerably more hardened as compared to that with cutting fluid delivered conventionally. Overall it was found that cutting fluid water vapour imparted better characteristic machining induced hardening as compared to machining under dry conditions and chilled air.