Comparison between sustainable cryogenic techniques and nano-MQL cooling mode in turning of nickel-based alloy

Abstract

Mineral based metal working fluids used in machining, results in environmental pollution and occupational health hazards for the operators. Consequently it is necessary to evolve out machining techniques which are environment friendly. In the present work, techniques such as cryogenic cooling and cryogenic treatment have been compared with Al2O3 nanoparticles based MQL cooling method (nMQL) in turning of the nickel based Nimonic 90 alloy. The machining of nickel based alloy has been carried out using the AlTiN coated tungsten carbide inserts of different nose radii. The effects of these cutting environments have been studied by comparing the tool wear, cutting forces, work surface defects, surface finish, and chip underside surfaces. The application of liquid nitrogen as a cooling medium significantly reduced the tool flank wear of the 0.2 mm nose radius insert by 38% as compared to nMQL technique. The SEM investigation of rake face revealed that the cryogenic cooling technique has also prevented the groove formation and peeling of the coating. The effective cushioning effect of liquid nitrogen as coolant improved the surface finish as compared to other techniques. The cryogenic cooling reduced the defects such as material side flow, material redeposition and micro cavities over the machined surface. Overall the cryogenic cooling environment has been found to be the best mode for the machining of the Nimonic 90 alloy.