INCREASED WEAR RESISTANCE AND RELIABILITY OF AUTOMATIC COUPLING BODY

The paper objective is the need to increase the operation reliability and durability of the automatic coupling body restored by welding. The paper presents the study results of borating from coatings using HFC heating, designed to increase the wear resistance of the surfaces of the coupler contour and the reliability of the coupling body. This method makes it possible to obtain borated layers of various structural modifications in a wide temperature range from 700 to 1300 °C by diffusion and diffusion-crystallization mechanisms, respectively. Compositions of saturating coatings based on boron carbide, up to 10 mm thick, were used. A protective coating based on sand and boric anhydride, up to 15 mm thick, was applied over the saturating coating. The work used metallographic, durometric methods of research and testing of wear resistance. The brittleness of the layers was assessed by determining the chipping stresses. The most suitable for strengthening the coupler contour is the composite structure of the borated layer, which was obtained for the first time of low-carbon steel. The increased reliability of the coupling body is ensured by correcting the dendritic structure of the deposited layer, correcting Widmanstätten structure of the sublayer, eliminating welding tensile residual stresses and establishing compressive residual stresses on the surface, as well as the wear-resistant properties of the composite borated layer, which is not brittle and has a high margin of plasticity.