Rezumat
CZU 544.558+66.088
DOI https://doi.org/10.52577/eom.2024.60.6.01
A technology is proposed to increase the hardness and wear resistance of the surface of R6M5 high-speed tool steel using low-temperature plasma electrolytic nitrocarburizing in combination with air quenching and three-stage tempering. The structure and phase composition of the surface layers of high-speed steel before and after treatment were studied using X-ray analysis and scanning electron microscopy. Tribological tests were carried out under dry friction conditions with a varying sliding speed. It is shown that the formation of a high-alloy martensite structure with nitride inclusions after nitrocarburizing with quenching and the precipitation of finely dispersed carbides during subsequent tempering leads to hardening of the surface layer to 1140 HV after quenching and to 1380 HV after subsequent tempering. The greatest reduction in weight wear (by 11.6 times) compared to that of the untreated sample occurs after plasma electrolytic nitrocarburizing with subsequent hardening and tempering under the condition of oxidative wear, which is observed at a load of 10 N and a sliding speed of 1.44 m/s. At both lower and higher sliding speeds in the studied friction pairs, wear is defined as fatigue wear with dry friction and plastic contact.
Keywords: high-speed steel, plasma electrolytic treatment, nitrocarburizing, quenching, tempering, microhardness, wear resistance, friction coefficient.