OPTIMIZATION MATERIAL FOR UNIT DAMPING OF THE VIBRA-TION OF THE TRAM FOR FREIGHT CAR

doi: 10.25712/ASTU.2072-8921.2021.02.032

Abstract

At present, industrial enterprises of the Russian Federation are serially producing friction wedges from steel grade 20L and cast iron SCh35. The main problems in the operation of cars equipped with such friction wedges are insufficient wear resistance and, as a result, a reduction in the overhaul mileage of the car as a whole. It is proposed to make a friction wedge structure from 50SL steel in order to increase the strength and wear resistance. Materials for friction pairs were selected in order to maximize coverage of all steels used for the manufacture of a friction wedge, including the proposed 50SL steel. To determine the tribological properties of the steel proposed for the manufacture of a friction wedge, samples were made to study the interaction of rubbing surfaces on a friction machine. The UMT 2168 friction machine was used as the test equipment. Analysis of the wear value of specimens made of steel 50SL showed that the total wear in friction pairs of steel 50 SL over steel 50 SL and 20L is, on average, 56 and 25% less weight loss in friction pairs 20L – 20L, 20L – 30HGSA, 50 SL – 30HGSA, respectively. Thus, according to test data, the most promising materials as a counter body for parts of steel 50SL are parts made of steels 50SL and 20L. The absence of a limiting state when a dynamic load was applied in the vertical direction was monitored on two samples by installing them in a tooling simulating the operation of a spring suspension of a freight car bogie. After bench tests, the limiting state of the friction wedges was reached when 2 × 10⁶ dynamic load cycles were applied in the vertical direction, in accordance with clause 5.1.4 of GOST 34503-2018.