Optimization of the EDM machinability of deep and shallow cryogenically treated corrosion-resistant superalloys

Abstract

In this study, machinability tests were carried out on a corrosion-resistant superalloy subjected to shallow and deep cryogenic treatment via electrical discharge machining and the effect of the cryogenic treatment types applied to the material on the electrical discharge machining processing performance was investigated. Experimental parameters, including pulse-on time (300, 400 and 500 μs), amperage (6 and 10 A) and material types (untreated and with shallow cryogenic treatment and deep cryogenic treatment), were used to construct the full factorial experimental design. The resulting average surface roughness (Ra) and material removal rate results were optimized using the Taguchi L18 method. According to the Taguchi-based gray relational analysis, the optimal parameters for both Ra and material removal rate were determined as cryogenic treatment, pulse-on time and amperage, respectively. The response table obtained using the Taguchi method showed the most effective factors as A1BlC3 for Ra and A2B2C1 for material removal rate values. According to the ANOVA results for determining parameters affecting performance, amperage was the most effective factor for average surface roughness and material removal rate, at 74.79% and 86.43%, respectively. When examined in terms of Taguchi-gray relational degrees, the optimal parameters for both Ra and material removal rate were observed in the experiment performed with the shallow cryogenic treatment sample at an amperage of 6 A and 300 μs pulse-on time.