Performance analysis of coated carbide tool in turning of Nimonic 80A superalloy under different cutting environments

Nimonic 80A is a difficult-to-machine nickel-based superalloy thanks to its superior tensile strength in high temperatures and oxidation resistance. However, cutting fluids applied to improve machinability performance during the processing of such materials increase tool life, while at the same time increasing machining costs and causing health and environmental problems. Thus, the present research has been focused on cutting tool life and wear characteristics and analysis of machined surface in turning of Nimonic 80A superalloy under different cutting environments namely dry, air-cooling and oil-spraying method. The performance of the coated tool has been characterized by using optical microscope, SEM and EDS analysis. The results of the tool life and microscopic analysis showed that the oil-spraying method has longer tool life than dry and air-cooling method in turning of Nimonic 80A alloy. Moreover, the volume of material removed has been modeled by response surface method for predicting tool performance under various machining conditions. Lastly, the microstructural and microhardness variations of the machined surface have been evaluated when the cutting tool reaching the wear criterion. The best performance in terms of tool life and surface integrity was obtained at cutting speed of 60 m/min in oil-spraying environment.