Surface Integrity and Metallurgical Characteristics of the EDMed Work Surfaces of A2 Tool Steel (SAE 304SS), Inconel 601 and Ti-6Al-4V: a Comparative Analysis

In the present work, a comparative analysis of surface integrity and metallurgical characteristics of the EDMed work surfaces of A2 tool steel (SAE 304SS), Inconel 601 and Titanium alloy (Ti-6Al-4V) has been attempted. Experiments have been conducted at different values of peak discharge current to study morphology as well as topographical features of the EDMed work surface in terms of surface roughness, surface crack density and thickness of the white layer. XRD analysis has also been carried out to understand metallurgical features (phases and precipitates, material migration) of the EDMed work surface. Results have been interpreted with relevance to EDS and micro-indentation hardness test data. The effect of peak discharge current on the EDMed work surface topography has also been examined. It was found that peak current has imposed a positive effect on surface crack density as well as white layer thickness irrespective of the work material chosen. Compared to 304SS and Inconel 601, cracks thus developed are more severe for the EDMed surface of Ti-4Al-6V due to formation of a hard TiC layer. The white layer is non-uniformly deposited over the EDMed surface of Ti-6Al-4V compared with 304SS and Inconel 601.