STUDY OF CORROSION CHARACTERISTICS OF 65G AND 45 STEELS BEFORE AND AFTER ELECTROLYTIC-PLASMA HARDENING

This article presents the results of studies of the corrosion resistance of steel grades 65G and 45, which were subjected to electrolytic plasma hardening (EPH). The main objective of the study was to identify changes in the corrosion properties of steels depending on the type of environment: water, urea, superphosphate and ammonium nitrate. The study showed that after EPH, the corrosion rate of steel 45 decreased by 8 times compared to the original sample, reaching a value of 2.58×10 −4 mm/year. For steel 65G, a significant improvement in corrosion resistance was also observed, especially in the environment of urea and superphosphate. The corrosion potential of these steels shifted to a more positive value, indicating an improvement in the protective properties of the surface. Polarization curves showed a decrease in the corrosion current for steel 45 before EPH in a solution of edible salt from 562.34 µA/cm² to 111.75 µA/cm² in urea, and to 132.67 µA/cm² in superphosphate. For steel 65G before EPH, the corrosion current in a edible salt environment was 67.23 µA/cm², decreasing to 57.28 µA/cm² in urea and to 60.73 µA/cm² in ammonium nitrate after the EPH process.. The results confirm that EPH significantly increases the corrosion resistance of the studied steels, which makes this treatment method promising for improving the durability of metal products used in aggressive chemical conditions.