MICROSTRUCTURE AND PROPERTIES OF STEEL AFTER PLASMA ALLOYING WITH BORON

Currently, one of the effective ways to increase the wear resistance of machine elements used in the mining industry, mineral extraction, manufacturing industry, and agriculture is plasma alloying. The work studies samples after plasma alloying with boron with various current parameters of 120A, 140A and 160A on steel 20. Microstructure studies, microhardness measurements, determination of the chemical composition and analysis of the phase composition of the alloyed layers were carried out. Based on the research results, it was noted that it is possible to obtain alloyed boride layers on steel using the plasma alloying method. It has been established that the surface of steel after alloying has different zones: hypereutectic, eutectic and hypoeutectic. The alloyed layer with a current of 120A has the highest microhardness value of 1265 HV. In the alloyed layer, the precipitation of boron cementite was observed around primary iron borides oriented perpendicular to the plane of the section. In addition, an increase in the plasma arc current leads to a decrease in the proportion of primary borides in the surface layer after alloying, and thus, to a decrease in microhardness.