ВЛИЯНИЕ АЗОТИРОВАНИЯ НА ПРОТИВОЗАДИРНУЮ СТОЙКОСТЬ КОНСТРУКЦИОННЫХ СТАЛЕЙ ПРИ КОНТАКТНОМ ВЗАИМОДЕЙСТВИИ

Abstract

We investigated pairs of reverse sliding friction and pairs that simulate the operating conditions of gear wheels in linear contact with sliding of roller samples. The intensity of wear (Ih), the coefficient of friction (f), the maximum permissible load (Pd), which determines the bearing capacity of the contact, and the critical pressure (Pcr), at which seizure are formed, were evaluated. It is shown that at a sliding speed of 0.19 m / s for a pair with a nitrided layer Pd = 40 MPa, Pcr ≥ 40 MPa, Ih = 0.8.10-9, f = 0.10; cemented - Pd = 20 MPa, Pcr = 25 MPa, Ih = 1.4.10-9, f = 0.13. Anti-seize resistance for pairs with a nitrided sample is 25-30% higher. An experimental assessment of the bearing capacity of the interface, the critical load at which scuffs are formed, showed a higher efficiency of nitriding in comparison with carburizing. The provisions on the structure of the nitrided layer are formulated, providing an increase in the performance of the friction pair: the formation of a surface layer above the diffusion zone, consisting of the ɛ-phase (Fe2-3N) in the nanocrystalline state. A thermodynamic hypothesis of the effect of nitriding on the seizure resistance of steel friction surfaces is formulated.