An Experimental Investigation on the Machinability of Inconel 718 at High Speed Turning

Superalloy, Inconel 718 is from the category of "Difficult to Cut" materials. The applications of Inconel 718 is not only limited to aerospace, gas turbine, marine, space applications but also to the chemical process industry, automotive sector etc. due to its unique properties which are desirable in the engineering applications. However, due to its peculiar characteristics, machining of Inconel 718 has poor machinability. The present work is a preliminary experimental study based on the Merchant metal cutting theory for Inconel 718. The experiments were carried out on Inconel 718 workpiece using plain tungsten carbide (K20) insert tools. The objective of this study is to evaluate machinability factors such as cutting force, chip compression ratio or chip reduction coefficient (ζ), shear angle (Φ) and specific cutting pressure using Taguchi's optimization approach. Also chip analysis was carried out by varying the cutting parameters. The mathematical model and the results are presented and analyzed in this paper.