Effect of Tool Electrode Resolidification on Surface Hardness in Electrical Discharge Machining

Since the recast layer affects the surface hardness of the workpiece in electrical discharge machining (EDM), it is very important to investigate the effect of the tool electrode on the machined surface. Owing to its importance in the locomotive structural elements, an attempt has been made to analyze the effect of EDM process on surface hardness of AISI 202 stainless steel with different tool electrodes such as brass and tungsten carbide. The investigation was carried out with various process parameters, and surface hardness values were computed using micro Vickers hardness tester. From the experimental results, it has been observed that the surface hardness of the workpiece increases with tungsten carbide tool electrode whereas it decreases with brass tool electrode due to the layer formation on the machined surface of the workpiece.