The study of the structure and properties of a friction composite material based on an iron matrix

Abstract

The continuous increase in the speed and load of railway transport operating in a wide range of climatic zones of the Russian Federation creates a need to develop new friction materials with the improved performance properties that can ensure high functioning reliability of the electric switch mechanisms. The paper presents the results of the study of the microstructure, physical, mechanical, and operational properties of a new material for friction inserts based on an iron matrix for the switch gear clutches. The new material composition includes such components as Fe, Cu, BaSO4, SiO2, C, and Zn. The authors propose a technique for selecting materials with the specified performance properties based on the results of the research carried out using the experiment factorial planning. For this purpose, the authors carried out the studies and established a relationship between the values of microstructure indicators, physical, mechanical and operational properties of the materials with different quantitative composition of components. The grain boundary density was proposed as an indicator of the dissipative properties of the material, and the possibility of its application as a structural parameter for evaluating the friction material performance characteristics. To assess the friction material performance characteristics, which determine the possibility of its application as a part of the friction clutches of the electric switch mechanism, the authors proposed a new parameter – the endurance period . Another service property was the deviation of the friction coefficient ƒ values in the range of values of the clamping force of the electric switch mechanism. According to the results of bench tests of a new friction material within the friction clutches of the electric switch mechanism, the authors identified a high wear resistance of the material and the possibility of its use in severe climatic conditions. The proposed testing technique allows predicting the performance properties of new materials at the stage of studying the microstructure based on the obtained dependences, which can significantly narrow the search range.