Abstract
The present work investigates the effect of addition of graphite powder in dielectric on the surface properties of superalloy Super Co 605 in electrical discharge machining (EDM) process. Addition of conductive powders in the dielectric medium affects the energy distribution and sparking efficiency by lowering the dielectric strength, which consequently alters the surface finish and micro-hardness after machining. These powders also form part of the plasma channel in the molten state and alloy with the recast layer under appropriate machining conditions. Experiments were carried out with graphite tool electrode. While the improvement in micro-hardness was found to be lower, surface finish improved significantly with powder-mixed dielectric. The results show that an optimization between micro-hardness and surface finish can be achieved by this method of machining. The polarity of machining, peak current and pulse on-time were found to have a significant effect on surface properties, whereas pulse off-time, discharge voltage and fluid pressure were insignificant factors. Scanning electron microscope (SEM) images of the surface reveal a smoother surface, and spectroscopy analysis indicates substantial increase in carbon percentage.
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Singh, A.K., Kumar, S. & Singh, V.P. Effect of the addition of conductive powder in dielectric on the surface properties of superalloy Super Co 605 by EDM process. Int J Adv Manuf Technol 77, 99–106 (2015). https://doi.org/10.1007/s00170-014-6433-z
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DOI: https://doi.org/10.1007/s00170-014-6433-z