Abstract
X40CrMoV51 alloy in the heat-treated (HT) and non-heat-treated (NHT) states processed by electro-discharge machining (EDM) with suspended tungsten compound powder has been rarely investigated. Hence, this study explored and compared the effect of control parameters, including peak-current (Ip), pulse-on time (Ton), and powder amount (Ap) on material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra) of the two material states, and finds an optimum combination of control parameters for each material state for improving the MRR, Ra, and TWR. With this goal, the predictive models for MRRht, MRRnht, TWRht, TWRnht, Raht, and Ranht were instituted, and also evaluated by the analysis of variance (ANOVA). The Grey Relational Analysis (GRA), Non-Dominated Sorting Genetic Algorithm II with Evaluated by an Area-based Method of Ranking (NSGA II-EAMR, and multi-objective particle swarm optimization with Evaluated by an Area-based Method of Ranking (MOPSO-EAMR) algorithms were executed for enhancing the MRR, Ra, and TWR. As a results, the influence of control parameters on MRR, TWR, and Ra for each material state is dissimilar. Regarding optimization results, the GRA produced the highest MRR value (MRRht = 0.0236 g/min and MRRnht = 0.0223 g/min). The NSGA II-EAMR offered the lowest TWRht and Raht, with a reduction in TWRht of 41.37% and Raht of 14.86% compared to GRA, and with a decrease in TWRht of 1.01% and Raht of 2.01% compared to MOPSO-EAMR. Meanwhile, the MOPSO-EAMR suggested the lowest TWRnht and Ranht, with a reduction in TWRnht of 45.49% and Ranht of 10.16% compared to GRA, and with a decrease in TWRnht of 4.23% and Ranht of 0.44% compared to NSGA II-EAMR. Additionally, the surface metallurgical features of two material states obtained from the optimum control parameters of NSGA II-EAMR and MOPSO-EAMR were explored. The results showed that the surface defects, micro-crack acreage percentage (MCAP), composition, content, and distribution of chemical elements, distribution and density of W2C phase, surface topography, thickness of recast layer (TRL) in two material states are different.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
