Influence of wolfram carbide on structure and phase composition of floating alloy PG-J40

Abstract

In order to study the influence of tungsten carbide, inserted into the composite filler powder PG-F40, on the structure of layers obtained at geothermal deposition on a steel substrate, their structure and phase composition were studied.It is shown that composite powder mixtures of the Ni-Fe-Cr system with reduced nickel content and additions of Cu, Mn, Si, C, Ti, V and B are promising surfacing materials. They are characterized by high wear resistance, corrosion resistance, crack resistance, lower cost in comparison with traditional structural alloys based on iron.Further increase in wear resistance of such materials can be achieved by the insertion of dispersed carbides, borides, silicides and other materials with high hardness.Composite powders of PG-J40 grade were obtained, in the composition of which VK8 powder was added in an amount of 1% by weight. Themethodofgas-thermal spraying of this powder was used to deposit the layer on a substrate of steel St3. The studies have shown that the fusion of the initial powders is provided at the selected deposition modes, but the concentration fluctuations comparable in size with the initial powders are detected.Particles of tungsten carbide and tungsten metal are exposed to the melt.It is shown that the process of the reaction of the interaction proceeds in two stages, first, tungsten carbide decomposes with the formation of carbide devilray, which is then interacting with the melt forms an intermetallic compound WCrFe.Crystals of this compound are allocated in the form of conglomerates and chains. In other phases, tungsten is practically not present. In the transition zone at the interface with the steel substrate in the solid solution, tungsten is not detected. It manifests itself only in the form of single tungsten-containing precipitates up to 100 nm in size. The obtained data allowed us to conclude that tungsten carbide, due to its high dispersion, can be used for the introduction of tungsten and carbon into the charge. The dispersed crystals of the intermetallic compound WCrFe formed in the deposited layer are characterized by high hardness, which increases its wear resistance.