Electro-Discharge Machining of Inconel 718 Using Square Cross Sectioned Copper Tool Electrode: Studies on Topography and Metallurgical Features of the EDMed Work Surface

Abstract

A case experimental research towards investigating aspects of Electro-Discharge Machining (EDM) on Inconel 718 super alloy using Copper tool electrode (of square cross section) has been delineated herein. Based on three controllable process variables viz. peak discharge current, pulse-on duration and gap voltage, experiments have been carried out to investigate their effects on influencing various process performance features in relation to surface topography like Surface Crack Density (SCD) and White Layer Thickness (WLT) onto the top surface of the EDMed end product. Additionally, EDAX analysis has been carried out to investigate the extent of carbon enrichment onto the machined surface as affected during pyrolysis of the dielectric fluid whilst executing EDM operation. XRD tests have been carried out to compare metallurgy (various phases/precipitates present in bulk of the matrix material, extent of grain refinement, crystallite size, and dislocation density) of the EDMed work surface with respect to ‘as received’ Inconel 718. Results obtained thereof have been interpreted in detail.