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,

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... ich 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.