Problematic issues of standardisation of foundry products (on the example of standardisation of railway brake pads)

Abstract

Using the example of brake pads for railway rolling stock, the article analyses trends and prospects for the development of the regulatory framework (standards, specifications, etc.) for these products made of various materials. A general description of brake pads made of cast iron and composite material (asbestos and asbestos-free rubber compound) is provided without reference to any specific enterprise or plant. The paper summarises the results of analytical and experimental studies and practical experience of using different brake pads in practice. The requirements of technical specifications and standards for railway brake pads made of cast iron and composite material (rubber compound) are compared. The disadvantages of the technical specifications for composite brake pads, including those with cast iron inserts, are the lack of requirements for the percentage of rubber compound components and their chemical composition. This violates Ukrainian law, as the chemical composition of any product must be specified in the technical specifications or product drawings. The article highlights the harmful effects on human health and the environment of wear products of composite brake pads. Areas for improving the regulatory framework for the production of brake pads from various materials, including standards and specifications for these products, include regulation of the percentage of components and their chemical composition in the composite material and possible correction of the ranges of chemical elements in the cast iron used to make cast iron brake pads. It is recommended that when improving standards and specifications for cast iron brake pads, attention be paid to the size and location of the ranges of carbon, silicon, manganese, phosphorus and the reduction of the permissible sulphur content to 0.05 %. In the standards for cast iron brake pads, it is advisable to perform shot blasting to facilitate the detection of possible surface defects in the pads. The requirements of European and other countries' standards for the development of standards for railway brake pads are considered. The technical specifications for railway composite brake pads in force in Ukraine should be identified in accordance with the European Union standards for these products. Attention is focused on urgent measures aimed at improving standards and specifications in this area.