Use of vortex tube air cooling during machining of Inconel 718: Experimental investigation and modeling studies

Abstract

Among Nickel based super alloys, Inconel 718 is a most widely used alloy, due to its superior properties like high temperature resistance, corrosion resistance, creep resistance, good mechanical properties etc. But, machining this alloy is a challenge even today because of its high temperature strength, hot hardness, wear resistance and work hardening and is considered as a ‘difficult-to-machine’ material. To overcome these problems, lubrication and cooling is an effective method and there have been several research studies aimed to reduce the machinability problems considering different cooling methods. But these methods have their own disadvantages and to overcome these and to support ‘sustainability’, air cooling is being adopted in a big way by machining industries. Thus, this research work focusses to experimentally investigate the effect of air cooling during turning of Inconel 718 using uncoated carbide inserts. The machinability is being evaluated in terms of cutting tool temperature, tool wear, surface roughness and cutting tool vibrations. Experiments are conducted at different speeds and feeds and results have been compared with dry machining. Further Random forest regression, a statistical technique is used to model surface roughness using data collected from air cooled experiments. It is found to be effective in modeling surface roughness, with a prediction accuracy of more than 89 % for Ra.