УДОСКОНАЛЕННЯ НОРМАТИВНО–ТЕХНІЧНОЇ ДОКУМЕНТАЦІЇ НА ЛИВАРНІ ВИРОБИ З ЧАВУНУ: Processy litʹâ, 2021, Tom 145, №3 p. 69-76

• Дата: 2021
• Автор: Сіренко, К. А.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: National Academy of Sciences of Ukraine, Physical-Technological Institute of Metals and Alloys of NAS of Ukraine 2021
• Теми: ливарне виробництво; гальмові колодки для залізничного транспорту; чавун; стандарти; технічні вимоги; технологічні інструкції; удосконалення
• Онлайн доступ: https://plit-periodical.org.ua/index.php/plit/article/view/74
• Назва журналу: Casting Processes

UDC 621.74:669.136.9 Recieved 10.08.2021 On the example of brake pads for railway rolling stock, trends and prospects for the development of the regulatory framework and technical documentation for the production of cast iron products are analyzed. In the range of foundry products, synthetic cast iron occupies a significant segment in terms of volume, including the production of brake pads for railway rolling stock. The advantages of the process of manufacturing brake pads from synthetic cast iron in comparison with the use of cupola cast iron are considered. An indicator of the quality of synthetic cast iron is the low level of its contamination by non-metallic inclusions in compliance with strict requirements for the structure and mechanical properties of the finished foundry. In synthetic cast iron, designed for the manufacture of brake pads, a special role is played by the size, shape and other parameters of graphite inclusions in its microstructure, which affect the mechanical and frictional properties of the material. Innovative technology of smelting of synthetic cast iron allows to receive necessary operational characteristics of brake pads. Problems have been identified regarding the compliance of regulatory and technical documentation that hinder the expansion of the production of cast iron brake pads for railway rolling stock. The directions of development of standards and technical conditions which regulate requirements to chemical composition, microstructure, plasticity and durability of material of such brake pads are offered. Analysis of the quality of foundry products from cast iron, which is smelted at Ukrainian plants, shows that the regulatory framework, technical documentation and technological instructions for its manufacture need to be improved by strengthening the requirements for the chemical composition and properties of cast iron. The improvement of ferroalloys used in the smelting of synthetic cast iron in electric induction furnaces creates the preconditions for reducing its contamination by harmful non-metallic inclusions and increasing the yield. This factor should be reflected in the standards on cast iron brake pads. As a result, opportunities to reduce metal costs and save electricity in industrial production will increase. Improving the requirements of standards and technical conditions for brake pads is one of the most important ways to reduce the cost of cast iron and reduce the specific consumption of cost ferroalloys and alloying elements by working on the lower limit of the chemical composition of the melt. The main parameters of the technology of manufacturing brake pads from synthetic cast iron, which are enshrined in the factory technological instructions, must be justified by the results of theoretical and experimental studies. The urgent task is to improve this technological documentation by reflecting modern scientific achievements and practical experience in optimizing foundry processes. In the technological instructions for the manufacture of brake pads for railway rolling stock it is necessary to provide material-energy modes of smelting of synthetic cast iron in modern electric induction furnaces. Based on the results of research performed, in particular, at the Institute of Physics and Technology of Metals and Alloys of the National Academy of Sciences of Ukraine and other scientific institutions, and practical experience of foundries, it is recommended to develop a standard technological instruction for the production of cast iron brake pads. In a typical technological instruction it is necessary to generalize and adapt to the production conditions of foundries scientifically sound and recognized in practice the technology of smelting synthetic cast iron for the manufacture of brake pads. Recommendations are given on the need to strengthen the requirements of standards and technical conditions for brake pads made of composite (rubber-asbestos and rubber-asbestos-free) materials for railway rolling stock. Mandatory requirement for standards and technical conditions for composite brake pads with cast iron inserts or without such inserts is the regulation of the components of the composite rubber mixture and their chemical composition. Increasing the requirements of standards and specifications for these cast iron products in general comes down to optimizing the permissible ranges of carbon, manganese, silicon, phosphorus and reducing sulfur. The need to solve at the state level the task of improving the standards for brake pads for the railway was emphasized. Manufacturers of synthetic cast iron need to expand the range of products they supply for export. To solve this problem, it is necessary to harmonize Ukrainian standards for foundry products with European ones. Insufficient attention is paid to this issue at the state level, which weakens the position of Ukrainian foundries in the domestic and foreign markets. State regulation of market relations between producers and consumers of cast iron products through the improvement of the regulatory framework is a necessary measure to ensure the development of the foundry subsector of the industrial complex of Ukraine.