Investigation of the structure and properties of the surface composite layer on VKS-5 steel

Abstract

Abstracts In this work, were studied the structure and properties of the surface composite layer on heat-resistant steel VKS-5, obtained by combined chemical and thermal treatment, combining liquid electrolysis-free boriding with gas and ion-plasma nitriding. The properties of the surface composite layer are analyzed depending on various parameters of chemical and thermal treatment to determine the optimal mode. The study of the microstructure and properties of borated layers has shown that the most optimal properties can be obtained in the boron mode at a temperature of 1010 °C with an exposure time of 8 hours. The study of the microstructure of composite layers has shown that gas nitriding produces a layer of 80 microns in size, which penetrates deep into the borated layer, and in ion-plasma nitriding, the layer size is so small that it is not possible to determine it using optical microscopy. A study of the properties of composite layers obtained by combined chemical-thermal treatment has shown that combined chemical-thermal treatment, combining boriding and ion-plasma nitriding, allows you to get the best combination of high hardness and reduced microfragility.

Investigation of the structure and properties of surface composite layers on multi-alloyed steels

“…It has been established that the microhardness distribution curve after boriding and gas nitriding has a significant gradient of microhardness values in the transition from the nitrided layer to the boron layer and then to the core. Such a distribution of microhardness, based on previous studies [13], suggests a decrease in microbrittleness and an increase in wear resistance.…”

“…The study of the microstructure of composite layers after combined chemical-thermal treatment, which combines boriding and subsequent gas nitriding, suggests a decrease in microbrittleness and an increase in the corrosion resistance of the coating [13]. An example of the microstructure of the composite layer is shown in Figure 6.…”

“…Other alloying elements (Cr, Si, Mo, V, etc.) have little effect on the layer morphology, but have a strong effect on the phase composition of the borated layers [11][12][13]. It was shown in [14][15][16][17] that the presence of chromium in steel in a significant amount makes it possible to obtain compact boride layers in which the chromium content is comparable to that in steel.…”

“…It was shown in [14][15][16][17] that the presence of chromium in steel in a significant amount makes it possible to obtain compact boride layers in which the chromium content is comparable to that in steel. In complexly alloyed steels, one can observe the precipitation of a dispersed strengthening phase both in steel and in compact boride layers [13,18].…”