Experimental Study of Electrical Discharge Machining of Inconel X-750 Using Tungsten-Copper Electrode

Abstract

Nickel-based alloys have wide applications in many industries due to their outstanding properties like high temperature, corrosion resistant and creep rupture. Inconel X-750, a Nickel based super alloy, precipitation hardenable material used especially in aircraft structures, rocket engine thrust chambers, gas turbines, nuclear reactors and pressure vessels due to its excellent properties. However, it is very difficult to machine using traditional methods due to their low thermal conductivity, strong strain hardening, and high strength at elevated temperatures. Therefore, electrical discharge machining (EDM), which is a thermal process irrespective of work piece hardness, is used to machine Nickel-based alloys by electrical erosion. In this process cu-w electrode was used as an electrode because of its excellent thermal properties and high thermal conductivity of copper component and low thermal expansion, high melting point of tungsten gives the better surface integrity on machining .The objective of this investigation is to optimize the EDM process parameters on Inconel X-750 alloy over the performance parameters like material removal rate (MRR), surface roughness (SR) and recast layer thickness (RLT) and to study the influence of operating parameters of tungsten-copper electrode on the machining characteristics .The experiments were performed based on one factor at a time approach. In this report, the considered input parameters like pulse peak current, pulse on time, pulse off time and type of electrode. It has been noticed that most of the authors focused on reducing the surface roughness and increasing the material removal rate using different materials like copper, graphite, brass. However, very few authors have been experimental investigated on Inconel X-750 with W-Cu electrode