Machinability study of austempered ductile iron using die-sinking EDM

Abstract

Austempered ductile iron (ADI) is a comparatively a new class of material having interesting properties. However, it is difficult to machine by conventional methods. Here we report the EDM processing response of ADI under various parametric conditions. The effect of peak current (IP), pulse on time (Ton) and dielectric flushing pressure (Pf) on response parameters: material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) are investigated. Study reveals that EDM can be used to effectively machine ADI under the investigated range. Results show that, increase in Ip and Ton increases MRR, TWR as well as SR. The MRR and TWR is found to first increase with the increase in Pf and at higher values of Pf both the MRR and TWR found to decrease. Surface micrographs of machined surface using scanning electron microscope (SEM) also reveal some initiation of micro cracks on the machined surface from the graphite-matrix interface.