OBRABOTKAMETALLOV Vol. 27 No. 1 2025 technology Conclusions 1. Mathematical models have been developed to simulate the impact of a unit pulse on the processed surface during CPEDM, enabling prediction of the white layer thickness based on the processing modes and properties of the workpiece material. The potential for using the developed model to predict the pit size and overall surface roughness has been noted. Theoretical values of the white layer thickness have been obtained for low-alloy 0.4 C-Cr steel and medium-alloy 0.35 C-Cr-Mn-Si steel. These theoretical values range from 20 to 25 μm for CPEDM at the minimum mode and from 60 to 80 μm at the maximum mode. For CPEDM using the same mode, the white layer thickness is greater for low-alloy 0.4 C-Cr steel than for medium-alloy 0.35 C-Cr-Mn-Si steel, which can be attributed to the higher thermal conductivity and lower melting point of 0.4 C-Cr steel. 2. Experimental values of the white layer thickness range from 20 to 25 μm with CPEDM at the minimum mode and from 55 to 85 μm at the maximum mode. The developed theoretical models for single-pit formation enable prediction of the white layer thickness with reasonable accuracy, based on processing parameters and the physical and mechanical properties of the workpiece material. The deviation between theoretical and experimental values of the white layer thickness is no more than 5%, confirming the validity of the models. 3. The continuity of the white layer is, on average, twice as great at the minimum mode as at the maximum mode. The continuity of the white layer is greater for 0.4 C-Cr steel than for 0.35 C-Cr-Mn-Si steel, by 10 % with CPEDM at the maximum mode and by 17 % with CPEDM at the minimum mode. 4. The number of microcracks formed during processing at the maximum mode is more than two times greater than that formed during processing at the minimum mode. The number of cracks in the white layer is comparable for 0.4 C-Cr and 0.35 C-Cr-Mn-Si steels, with the difference not exceeding 10 %. References 1. Hawryluk M., Lachowicz M., Zwierzchowski M., Janik M., Gronostajski Z., Filipiak J. Influence of the grade of hot work tool steels and its microstructural features on the durability of punches used in the closed die precision forging of valve forgings made of nickel-chrome steel. Wear, 2023, vol. 528–529. DOI: 10.1016/j.wear.2023.204963. 2. Zeisig J., Schädlich N., Giebeler L., Sander J., Eckert J., Kühn U., Hufenbach J. Microstructure and abrasive wear behavior of a novel FeCrMoVC laser cladding alloy for high-performance tool steels. Wear, 2017, vol. 382– 383, pp. 107–112. DOI: 10.1016/j.wear.2017.04.021. 3. Rogal L., Dutkiewicz J., Szklarz Z., Krawiec H., Kot M., Zimowski S. Mechanical properties and corrosion resistance of steel X210CrW12 after semi-solid processing and heat treatment. Materials Characterization, 2014, vol. 8823, pp. 100–110. DOI: 10.3329/jname.v7i2.5309. 4. Dou C., Pan K., Wang C., Wei S., Zhang C., Xu L., Cui H., Liang Y., Huang J. A comparative study on the erosion behavior and mechanism of chrome-coated 25Cr3Mo2WNiV steel and QPQ 25Cr3Mo2WNiV steel. Materials Today Communications, 2024, vol. 41. DOI: 10.1016/j.mtcomm.2024.110820. 5. Abbas M.N., Solomon D.G., Bahari Md. A review on current research trends in electrical discharge machining (EDM). International Journal of Machine Tools and Manufacture, 2007, vol. 47 (7), pp. 1214–1228. DOI: 10.1016/j. ijmachtools.2006.08.026. 6. Liao Y.S., Chen S.T., Lin C.S. Development of a high precision tabletop versatile CNC wire-EDM for making intricate micro parts // Journal of Micromechanics and Microengineering. – 2005. – Vol. 15. – P. 245–253. – DOI: 10.1088/0960-1317/15/2/001. 7. Yoo H.K., Kwon W.T., Kang S. Development of a new electrode for micro-electrical discharge machining (EDM) using Ti(C, N)-based cermet. International Journal of Precision Engineering and Manufacturing, 2014, vol. 15 (4), pp. 609–616. DOI: 10.1007/s12541-014-0378-x. 8. Hoang K.T., Yang S.H. A study on the effect of different vibration-assisted methods in micro-WEDM. Journal of Materials Processing Technology, 2013, vol. 213 (9), pp. 1616–1622. DOI: 10.1016/j.jmatprotec.2013.03.025. 9. Hoang K.T., Yang S.H. A new approach for micro-WEDM control based on real-time estimation of material removal rate. International Journal of Precision Engineering and Manufacturing, 2015, vol. 16 (2), pp. 241–246. DOI: 10.1007/s12541-015-0032-2. 10. DebroyA., Chakraborty S. Non-conventional optimization techniques in optimizing non-traditional machining processes: a review. Management Science Letters, 2013, vol. 4 (1), pp. 23–38. DOI: 10.5267/j.msl.2012.10.038.
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