Optimizing machining processes used for high chromium steel

Abstract

End milling (EM) and electric discharge machining (EDM) are frequently used for machining high chromium steel. The superior surface finish is among the key requirements for the improved functional behavior, wear resistance, and fatigue life high chromium steel components. The present work includes optimization of EM (using Taguchi method) and EDM processes (by selecting appropriate electrode) for machining of the high chromium steel keeping high material removal rate (MRR) and superior surface finish as the objectives. Additionally, the effect of coolant on surface roughness was evaluated. For EM, the feed rate was found the most influential parameter and the high spindle speed, small feed rate result-in better surface finish whereas the depth of cut has the insignificant effect on the surface roughness for the selected rages of process parameters. The scanning electron microscope (SEM) micrographs revealed that flood cooling decreases the surface defects and mostly high chromium steel samples were having a lower surface roughness when coolant was used. For EDM, the brass electrode results in a superior surface finish but a lesser MRR than the copper electrode while machining high chromium steel.