Abstract. In the study, experiments with a vanadium coating of samples were conducted, to establish the limits of the increase in the landing dimensions and the designation of limiting deviations in dimensions and the designation of limiting deviations in the dimensions of the manufactured parts. The maximum deviations relative to dimensions of cast iron parts with thermal diffusion platings vanadium and chrome in friction knots of machines and mechanisms were explored. The plate thickness and the linear sizes increment of gray and nodular cast iron hardened products were determined. Were obtained uniform in thickness carbid platings as a result of the experiments on producing of thermal diffusion vanadium and chrome plating.

Abstract. The article presents the calculations of diffusion indices of saturation of high-strength cast iron VCh 60 from powder filling. Carbide-forming elements were used as diffusers: vanadium, chromium and manganese. As a result of the research, empirical equations have been established for predicting the thickness of strengthening diffusion coatings depending on the temperature and saturation time.

Replacing steel parts with cast iron is a promising task for agricultural engineering. However, high-strength cast iron VCh 60, widely used in mechanical engineering and studied in this work, is inferior in abrasive resistance to steel parts that have undergone chemical-thermal and subsequent heat treatment. This disadvantage was eliminated by the formation of high-hard diffusion coatings with vanadium or chromium, by the method of saturation of their powders. But these coatings, despite their hardness, are brittle and lie on a softer base of cast iron. This paper estimates the minimum thickness of the above-mentioned coatings that can withstand the specified level of contact load without destruction when solid non-crushed soil particles or particles of other origin enter the interface. Based on the conducted research, the empirical dependences of the minimum thickness of the coating that can withstand a given level of load without destruction are derived from the size of the resulting imprint of the Vickers pyramid pressed into the surface. The graphs are convenient to use when designing gears and worm gears with a given contact load in the engagement, the part of the space located above the critical line 6 in the figures shown in the work is a safe area of coating thicknesses at the identified contact pressure.

The application of stale and newly formed dump converter slags as raw materials for the creation of diffusion protective Nickel-Cobalt coatings is considered. The possibilities of chlorination of Nickel-containing phases, the chemical composition and diffusion parameters of the process are investigated.

The article is concerned with wear resistance increase of saw-tooth enclosed drives applying instead of iron gear wheels, made from cement steel quality, gear wheels from high-duty cast iron of HF 60 with thermodiffusion carbide layer. Elements- diffusants were chosen according to level of carbide forming and hardness of formed layersvanadium- for forming very hard, chrome-medium according to coating and manganese- for low layers according to coating hardness. Layers are formed on spur gears, which are reverse gear of light vehicle. Setting for research included draw gear- asynchronous electric drive, placed on lathe-bed with the help of which rotation of gear shift transmission with powered reverse gear was done. Transmission output shaft was pressed into chunk. Kinematick of disconnected machine provided necessary moment resistance. Through given number of cycles the box was taken down, gear set was removed and metal graphic research was carried out. Residual layer thickness and linear wear were diagnosed, on the basis of obtained experimental data we built characteristic curves of linear wear from number of stress cycles. For comparative evaluation in this type of research we carried out experiments on measurement of linear wear of case – hardening steel 20 ChGn after cementation and further quenching and research of hardened cast iron HF mark 60. It was found out that the highest quality wearing in this type of research vanadium layers have, slightly lower quality wear chromium plate have and on the 3rd place manganese layers. The worst quality wear we observed in steel 20 ChGN. On the basis of obtained –experimental data empirical regularities of wear rate of layers from their Brinnel hardness and diameter of obtained copy were determined.