Abstract
The influence of the carbonitration medium on the distribution of chemical elements (C, N) and the change in microhardness over the depth of the surface layer formed during carbonitration is considered. The carbonitration operation was performed in 2 stages. During the first stage, cementation was performed at a temperature of 950°C for 40 minutes in a C2H2 medium at a flow rate of 0.5 to 3.0 liters per minute. During the second stage, nitriding was performed in N2 medium at a temperature of 850°C for 40 minutes at a constant nitrogen consumption of 1.5 liters per minute. Steel grade 20CrMo was used as the object of the study. It was shown that the carbonitration process of 20CrMo steel followed by high-frequency current quenching led to a significant increase in surface hardness. The distribution of chemical elements over the depth of the surface layer is not uniform: the carbon content changes gradually over the depth of the surface layer, while the presence of nitrogen is not fixed already at a depth of 200 μm.