Complex examination of breaches of fastening partsof rolling stock by metal-graphic analysis methods

The article is devoted to the analysis of the quality of materials for the manufacture of fasteners for rolling stock. The paper presents the results of studies of parts destroyed during operation that are used for fastening the undercarriage assemblies, spring suspension and impact-traction devices of rolling stock. The purpose of the work is to establish the probable causes of the destruction of parts under the action of static and dynamic loads during movement on the track. The paper describes the methodology and sequence of examination of materials based on the analysis of the chemical composition of metals, the assessment of mechanical properties and the study of the surfaces of fractures of parts. The results of spectral analysis of the metal of the investigated parts, measurements of hardness and analysis of the surface of fractures of the parts are presented, which allowed to establish the possible nature, sequence and causes of their destruction. The results obtained in the course of the research showed that the main reason for the breaks in the fasteners of rolling stock is the impact on them of loads exceeding the tensile strength of the metal. It was found that the brand used in the production of metal does not meet the requirements of the normative-technical documentation for the product and is not intended for the manufacture of fasteners. Thus, the findings confirm the need to tighten the quality control of materials used in the manufacture of fasteners for rolling stock, and can be used in machine-building enterprises specializing in the production of components and spare parts for railway rolling stock. The main conclusion of the work is the need to use in the production of fastening parts of the responsible components and assemblies of rolling stock, structurally reasonable steels and alloys.