STRUCTURAL CHANGES OF 65G STEEL DURING ELECTROLYTIC PLASMA HARDENING

In this work, the effect of the electrolytic plasma hardening (EPH) method on 65G steel was investigated. Prior to the study, the surface of the specimens was mechanically leveled and subsequently subjected to grinding and polishing operations, which ensured the complete removal of initial surface defects and foreign layers. During the experiments, a 20% sodium carbonate solution was used as the electrolyte, and EPH was applied to three specimens at different heating durations. It was shown that the initial microstructure of the material consists of ferrite and pearlite structural constituents.

As a result of hardening, austenite transforms into martensite, forming an extremely fine needle-like structure. Images obtained using a scanning electron microscope demonstrated that electrolytic plasma treatment significantly modifies the structure of the surface layer: grain refinement occurs, carbide phases are formed, and the microhardness of the surface layer increases substantially. It was proven that martensite formation and the influence of the alloying element manganese on the hardenability of the steel make it possible to increase hardness by 3.1-3.56 times.

The research results indicate that electrolytic plasma hardening improves the microstructure and mechanical properties of 65G steel, enhancing the strength and reliability of treated steel components and extending their service life. Therefore, this method can be considered a promising and efficient technology for manufacturing springs, shafts, gears, and other critical parts operating under heavy loads and friction conditions in mechanical engineering, transport, and agricultural machinery.

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