Probabilistic optimization of machining of duplex stainless steel in electric discharge machining with hydroxyapatite nanoparticles mixed dielectric medium

The electric discharge machining has been carried out in the current study for the surface modification of Duplex Stainless Steel (DSS 2205). The machining process is carried out in the hydroxyapatite nanoparticles (Ca5(OH)(PO4)3) (HAP powder) mixed dielectric medium with a copper tungsten electrode in reverse polarity. To determine the optimal machining parameters, the Taguchi L18 orthogonal array approach was employed, and the input machining variables in terms of discharge current, voltage, pulse-on time and pulse-off time were chosen. It has been observed from the results that the discharge current contributing 58.18%, pulse-off time contributing 16.77% and pulse-on time contributing 15.83% were the most significant factors in improving the MRR. The optimum machining parameters for achieving the maximum MRR (0.305 mg/min) with EDM Oil were recognized at discharge current of 16 Amp, pulse-on time of 200 ls, pulse-off time of 60 ls and the applied voltage of 80 V and with nano powder mixed electric discharge machining, the maximum MRR (0.271 mg/min) were observed at discharge current of 16 Amp, pulse on time of 150 ls, pulse off time of 60 ls and voltage 80 V. MRR is reduced by 11% when NPMEDM is used. XRD analysis confirms the modification on the surface of nano powder mixed electric discharge machining demonstrating the formation of several intermetallic compounds.Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Latest Developments in Materials & Manufacturing.