Iron-based alloys began to be used so long ago that today they are classified as classical materials, since these alloys have been studied in depth. The production of various products from steel and cast iron naturally takes the first place in terms of volume, since they have a valuable set of properties: a wide range of plasticity and strength, unique technological properties, which makes it possible to apply all technological operations to them - from simple casting into earth to complex pressure treatment processes. This combination of properties provides, first of all, the composition of iron-based alloys with the main alloying element – carbon. The serious disadvantage of ferrous alloys is their low level of corrosion properties. To eliminate this drawback, both steel and cast iron are alloyed with such metals as chromium, nickel, cobalt, etc. Naturally, this leads to an increase in the mass of finished products and structures. Therefore, the search for alloying elements to improve and optimize the composition of ferrous alloys is relevant today. On the other hand, the industry of Uzbekistan produces a sufficient amount of transition, rare earth metals. Thus, the task is to get added value from the production and processing of these non-ferrous metallurgy products. The analysis of the known literature data on this topic shows that research has been carried out on the use of various transition and rare earth metals for alloying ferrous alloys. However, the available scientific results do not allow to speak about systemic knowledge about the use of rare earth and/or transition metals as effective additives for steels and cast irons. The authors studied phase equilibria, determined the compositions of the phases and the reactions occurring in the systems, constructed phase diagrams, their isothermal sections, determined the structure of iron-based alloys with additions of rare-earth and transition metals with all structural components. The prospect of using the products of nonferrous metallurgy of Uzbekistan for the production of high-quality steels and cast irons is shown.

At the Navoi Mining and Metallurgical Combine, which uses a large number of machine parts for mining operations, the issue of optimizing the compositions of wear-resistant chromium cast irons while maintaining their operational characteristics has arisen. The paper presents the results of studying the phase composition of the cast alloy, as well as the effect of heat treatment of cast iron with a high chromium content on its structure and properties. As heat treatment operations, quenching in various modes and low tempering were used. The study made it possible to systematize the known literature data on the heat treatment parameters of a group of wear-resistant chromium cast irons, as well as to optimize their heat treatment modes for parts operating in mining and processing industry.

The mining industry of Uzbekistan uses hundreds of tons of white wear-resistant cast iron monthly for the manufacture of parts for machinery and equipment that extract natural raw materials. Only the Production Association Navoi Machine-Building Plant (PO «NMZ») monthly produces cast parts from wear-resistant high-chromium alloyed white cast iron with a volume of more than 120 tons per month. Most of the parts are made for rock crushers; their wear during work in mines shortens the service life of machinery and equipment. Parts of foreign equipment: dredge pumps, lining of grinding mills, hydraulic transport and others are made of white cast iron, highly alloyed with chromium, nickel, copper, titanium and other chemical elements. The annual import into the republic of parts made of cast irons of complex chemical composition requires signifi cant costs. In order to save money by refusing to import parts, a domestic wear-resistant white cast iron of grade 280Kh29NL was developed, from which rubbing parts, operating under wear conditions in mines, for mining equipment are cast in the foundry of the Navoi Machine-Building Plant. Considering that ferroalloys for the production of cast iron are also imported, the cost savings in the production of mining equipment parts instead of worn-out ones is insignificant. The purpose of this work is to optimize the composition of highly alloyed wear-resistant white cast iron for its replacement in industry with an economically alloyed analogue, as well as to improve the structure of the composition-optimized white wear-resistant cast iron to obtain the required level of performance properties of parts operating under friction and wear conditions. For this, phase transformations, the structure and properties of white cast iron, and the conditions for casting parts were studied. Based on the research results, recommendations were developed for economical alloying and casting technology for friction and wear parts.