Title: Surface alloying of OHNS die steel by EDM process using Inconel electrode

Authors: Sanjeev Kumar, T.P. Singh, B.L. Sethi

Addresses: Department of Mechanical Engineering, Punjab Engineering College, Chandigarh – 160 012, India. ' Department of Mechanical Engineering, Thapar University, Patiala – 147 004, Punjab, India. ' Department of Mechanical Engineering, Maharishi Markandeshwar Engineering College, Mullana, Haryana, India

Abstract: The last decade has seen an increasing interest in the application of electrical discharge machining (EDM) as a surface modification process. Erosion of the tool material takes place during machining and some of it gets alloyed with the work piece surface. Deliberate material transfer may be carried out by using composite electrodes or by dispersing metallic powders in the dielectric medium. This paper reports the results of experimental investigations into electrical discharge machining of OHNS die steel with Inconel (an alloy of chromium, nickel and iron) electrode under machining conditions favouring high electrode wear. For comparison, the work material was also machined with copper electrode. Results show 88% improvement in micro-hardness of the machined surface. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis reveal transfer of chromium and nickel from the tool electrode. Chemical composition of the machined surface was further checked on optical emission spectrometer.

Keywords: electrical discharge machining; electro-discharge machining; EDM; Inconel alloys; OHNS die steel; surface alloying; electrode wear; microhardness; chromium transfer; nickel transfer; tool electrodes; chemical composition; surface composition.

DOI: 10.1504/IJMMM.2009.027323

International Journal of Machining and Machinability of Materials, 2009 Vol.6 No.3/4, pp.176 - 193

Published online: 20 Jul 2009 *

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