Environment Friendly Machining of Inconel 625 under Nano-Fluid Minimum Quantity Lubrication (NMQL)

Superalloy Inconel 625 although having many industrial applications owing to its high strength, exhibits poor machinability because of its sticky nature and poor heat conductivity. To improve its machinability, use of cutting fluids becomes necessary to remove heat and provide lubrication in the cutting region. However, harmful effects of cutting fluids on environment and operator health restrict their application. Several efforts have been carried out to replace or minimize the quantity of conventional cutting fluids used in machining to strive for green machining and economizing machining operations. Nano-fluid minimum quantity lubrication (NMQL) technique has evolved as best alternative to flood conditions cooling /lubrication especially for machining of alloys like Inconel. This paper experimentally investigates the suitability of NMQL (carbon nanotube; CNT in vegetable oil) in machining of Inconel 625. The objective was to minimize tool wear and surface roughness under different machining conditions. Tool performance in NMQL was also compared with that under dry and flood conditions. The results revealed superiority of NMQL in terms of better tool life and improved surface finish over dry machining and nearly equivalent performance to wet (flood) machining thus provides the way forward for sustainable and environmental friendly machining.