OBRABOTKAMETALLOV Vol. 28 No. 3 2026 109 TECHNOLOGY Infl uence of high-frequency electromagnetic fi eld-assisted TIG surface modifi cation on microstructural evolution, elemental redistribution and hardness of EN-GJV-400 compacted graphite iron Farhad Mahammad oglu Shirzadov a, * Azerbaijan Technical University, 25 H. Javid Avenue, Baku, AZ1073, Azerbaijan a https://orcid.org/0009-0006-9378-9865, farhad.shirzadov@aztu.edu.az Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2026 vol. 28 no. 3 pp. 83–111 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2026-28.3-83-111 ART I CLE I NFO Article history: Received: 07 July 2026 Revised: 15 July 2026 Accepted: 17 July 2026 Available online: 15 September 2026 Keywords: EN-GJV-400 TIG remelting High-frequency electromagnetic fi eld Solidifi cation behavior Surface engineering Acknowledgments The author acknowledges that part of the experimental investigations was conducted at the Technical University of Berlin (Germany) within the framework of scientifi c cooperation and research activities related to surface engineering technologies. The authors’ current institutional affi liation is Azerbaijan Technical University, where the research work was further developed and prepared for publication. The experimental facilities and scientifi c support provided during the research stay at TU Berlin are gratefully acknowledged. ABSTRACT Introduction. Compacted graphite iron (EN-GJV-400) is widely used for highly loaded automotive and engineering components due to its favourable combination of strength, thermal conductivity, damping capacity and castability. However, the relatively moderate hardness and wear resistance of its surface region may limit its application under severe contact conditions. High-frequency electromagnetic fi eld (HFEMF)-assisted treatment represents a potential approach for modifying solidifi cation conditions and improving structural uniformity during surface engineering. Nevertheless, the infl uence of HFEMF-assistedTIG treatment on themicrostructural evolution, elemental redistribution and hardness response of compacted graphite iron remains insuffi ciently understood. Materials and methods. In this study, conventional and HFEMF-assisted TIG surface modifi cation of EN-GJV-400 compacted graphite iron was investigated. The experimental program included TIG remelting, TIG surface alloying using Ni78Si8B14 and CuSn-4 foils, and TIG hardfacing using UTP A DUR 600 chromium-containing fi ller wire, performed with and without electromagnetic assistance. A high-frequency electromagnetic fi eld with a frequency of 200 kHz was applied during treatment. The modifi ed surface layers were characterized using optical microscopy, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS) and Vickers microhardness measurements. Results and discussion. The obtained results indicate that HFEMF-assisted processing infl uences the structural development of TIG-modifi ed layers by aff ecting the conditions of heat and mass transfer during melting and solidifi cation. The infl uence of HFEMF was evaluated indirectly through surface morphology, microstructural characteristics, elemental distribution and hardness response. Conventional TIG remelting increased the surface hardness of EN-GJV-400 from approximately 375 HV0.1 to 765 HV0.1 due to graphite dissolution, carbon redistribution and formation of ledeburitic structures containing cementite-rich constituents. HFEMF-assisted remelting produced a comparable hardness level of approximately 760 HV0.1, indicating that electromagnetic assistance does not act as an independent strengthening mechanism but mainly contributes to structural homogenization. Ni78BSi8B14 alloying resulted in hardened transformation products together with ledeburitic and carbide-containing constituents, while HFEMF primarily improved the uniformity of alloy-element distribution. For UTP A DUR 600 hardfacing, HFEMF-assisted treatment increased the average hardness from approximately 771 HV0.1 to 800 HV0.1, which is attributed to improved redistribution and more uniform formation of chromium-containing hard phases. Conclusion. The results demonstrate that HFEMF-assisted TIG treatment provides an additional process-control parameter for surface modifi cation of EN-GJV-400 compacted graphite iron. The eff ectiveness of electromagnetic assistance depends on the chemical composition of the modifi ed layer and the dominant strengthening mechanism. HFEMF should therefore be considered primarily as a method for improving structural uniformity, elemental redistribution and phase distribution rather than as a universal hardness-enhancement technique. Further studies involving direct molten-pool observation and numerical modelling are required to quantitatively establish the relationship between electromagnetic parameters and melt-pool behaviour. For citation: Shirzadov F.M. Infl uence of high-frequency electromagnetic fi eld-assisted TİG surface modifi cation on microstructural evolution, elemental redistribution and hardness of EN-GJV-400 compacted graphite iron. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2026, vol. 28, no. 3, pp. 83–111. DOI: 10.17212/1994-6309-2026-28.3-83-111. (In Russian). ______ * Corresponding author Shirzadov Farhad Mahammad oglu, Ph.D (Engineering), Associate Professor Azerbaijan Technical University, 25 H. Javid Avenue, AZ1073, Baku, Azerbaijan Tel.: +994559029446, e-mail: farhad.shirzadov@aztu.edu.az
RkJQdWJsaXNoZXIy MTk0ODM1