Sustainability analysis of new hybrid cooling/lubrication strategies during machining Ti6Al4V and Inconel 718 alloys

Abstract

The necessity of achieving sustainable manufacturing processes, taking into account the economic and environmental balance, is a significant obstacle for many industries. This article investigates the comparative sustainability assessment of two difficult to cut superalloys (Ti6Al4V and Inconel 718) using a new hybrid sustainable machining strategy that combines ultrasonically assisted turning (UAT) with an environmentally friendly cooling and lubrication method (MQL and LCO2). The primary objective of this study is to examine the effects of the proposed strategy on the economic and carbon emission analysis, tool life, energy consumption, and surface roughness of Inconel 718 and Ti6Al4V alloys during machining. To evaluate the efficacy of the proposed strategy for the two alloys, an in-house UAT setup is used to conduct experiments employing a variety of cooling methods. It was found that Ti6Al4V emits roughly 40% less carbon than Inconel 718. The cost of machining Ti6Al4V and Inconel 718 in a cryogenic environment decreased by about 26% and 21%, compared to a dry environment. Moreover, while machining Ti6Al4V, more tool life has improved approximately by 6–65% and 9–35% compared to Inconel 718 in CT and UAT. Machining of Ti6Al4V consumes approximately 2–16% and 9–15% less energy compared to Inconel 718 under CT and UAT, respectively. Ti6Al4V lowers the surface roughness approximately by 21% and 15% compared to Inconel 718 when using CT and UAT, respectively.