Abstract WEDM is one of the precise and modern machining path leading in obtaining the efficient manufacturing techniques. In view of machining nickel–chromium alloy, one of the hard-to-cut materials, present paper deals with electro-machining of Inconel 600 using un-treated brass wire. Experiment has been conducted with varying in current, pulse on and pulse off time at constant voltage and di-electric fluid flushing rate. To minimize the experiments and material, a design of experiments was employed based on the L9 orthogonal array was selected. In WEDM pulse rating plays a critical role on surface roughness and material removal rate. Therefore the investigation was carried out to correlate best optimum conditions favouring for lower surface finish and higher material removal rate. Mathematical regression is carried out at alpha of 0.5. Anova analysis was carries out and found that for surface roughness and material removal rate current is most contributing parameter. A mathematical models has been generated in co-relation with input parameters and found that for surface roughness Rsq is 93.32 and for material removal rate Rsq is 92.37.