The impact of technological parameters of electrolytic-plasma treatment on the changes in the mechano-tribological properties of steel 45

Abstract

<p>This article presents the results of research on the effects of electrolyte plasma hardening on the structure, phase composition, tribological, and mechanical properties of medium-carbon structural steel 45, which is widely used in the manufacturing of tools and machine parts. Hardening experiments were conducted using an electrolyte plasma hardening setup with electrolytes varying in sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>) concentration in distilled water (15%, 20%, and 25%). With a consistent heating duration of 4 s during quenching, significant phase changes in the steel's microstructure were observed, enhancing hardness and wear resistance. The transformation of the initial structure of steel 45, which consists of ferrite and pearlite into martensite on the surface of the samples, led to an increase in microhardness up to 506–690 HV<sub>01</sub>. This value is 2.5–3.5 times higher compared to the untreated sample, and the thickness of the hardened layer reached up to 3.2 mm. Additionally, wear volume measurements showed that after electrolyte plasma hardening, the wear resistance of the samples increased by 1.3–1.5 times (2.01 × 10<sup>−4</sup>, 2.26 × 10<sup>−4</sup> m<sup>3</sup>). The obtained results on the changes in microstructure and mechano-tribological properties of steel 45 confirm the potential of electrolyte plasma hardening technology for improving operational characteristics and extending the service life of heavily loaded and critical machine parts.</p>