OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 1 2024 cryogenic treatment in an experimental study conducted by Nadig et al. [27]. The thermal conductivity was only marginally enhanced by tempering as compared to cryogenic treatment. The results pave the way for further research to optimize temperature and duration of cryogenic treatment as well as other tempering parameters. During the EDM of high-speed steel M2, Srivastava and Pandey [28] assessed surface roughness (SR), material removal rate (MRR), and electrode wear ratio (EWR) using an ultrasonicassisted cryogenically cooled copper electrode. The discharge current, duty cycle, gap voltage, and pulseon time were the variables that could be adjusted during the process. In the electrical discharge machining process, three types of electrodes were compared: conventional, cryogenically cooled, and cryogenically cooled together with ultrasound. The MRR, EWR, and SR were measured. The reattachment of particles to the machined surface caused major diffi culties in dry EDM, according to Liqing and Yingjie [29]. Their research proposed two methods for increasing MRR in dry EDM: the fi rst involves the use of cryogenically cooled workpieces, and the second involves the use of dry EDM in combination with oxygen gas. Electrical resistivity, crystallite size, microhardness, and microscopic studies were provided by Jaff erson and Hariharan [30], and a comparison of the machining performance of cryogenically treated and untreated microelectrodes in MEDM was carried out. The eff ect of cryogenically treated tool electrodes on electrical discharge machining (EDM) processes was studied by Mathai et al. [31]. When machining is performed using electrodes subjected to cryogenic treatment of varying durations, the effi ciency of the process is examined by examining the change in critical response characteristics, such as MRR, TWR, and surface roughness, with respect to current and pulse-on time. The study conducted by Singh et al. [32] aimed to evaluate the eff ectiveness of the copper electrode manufactured through a novel fast manufacturing process in EDM on D-2 steel. On the other hand, Prakash et al. [33] focused on comparing the performance of untreated and cryogenically treated micro-EDM tool electrodes while machining the magnesium alloy AZ31B. The tool electrodes were subjected to cryogenic treatment to enhance its mechanical characteristics, such as hardness and wear resistance, which in turn improved the quality of the machined features. A group of researchers optimized the process parameters using multi-criteria decision-making (MCDM) during the EDM of AA6061-T6 SiC composites (15 wt. % SiC) [34]. Attempts were made using supervised machine learning to predict the EDM surface roughness of deep cryogenically treated NiTi, NiCu and BeCu alloys [35]. [35]. A review of the literature showed that the research on electrical discharge machining of BeCu alloys is still in its infancy. Furthermore, the cryogenic treatment of workpieces and electrodes in EDM has not received much attention from researchers. Moreover, the impact of magnetic fi eld strength on surface integrity and productivity during EDM has received very little attention in research. Therefore, the goal of this study is to ascertain how the material removal rate, thickness of the white layer, and creation of surface cracks are aff ected by a cryogenically treated workpiece and electrode, magnetic strength, gap current, and pulse on time. In addition, this study makes use of machine learning regression algorithms to estimate the MRR. The remainder of the work consists of sections devoted to materials and methods, results and their discussion, as well as conclusions. Materials and Design In this study, an Electronica Machine Tools Limited die sink-type electrical discharge machine, model C400x250, was used for testing. A block of 100×100×50 mm in size was used as a workpiece in this study, which was then divided into blocks of 30×20×20 mm in size for carrying out experiments. Copper with high thermal conductivity was used as the tool electrode material in the experiments. The tool had a square shape with dimensions of 6×90 mm, respectively. Using an indexing system and a milling machine, it was given a 3×25 mm square shape. During the experiment, an external magnetic fi eld was applied using a neodymium magnet surrounding the cutting zone. The workpiece and tool electrodes were cryogenically prepared prior to the experiment. Electrical resistance/conductivity tests were conducted to determine how cryogenic treatment aff ected the materials. The weight of the workpieces and tool electrodes was measured using a computerized weighing
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