Almalyk State Technical Institute, Almalyk, Uzbekistan

U. M. Khalikulov, Dr. Eng., Associate Prof., Acting Rector, e-mail: utkirhm@mail.ru

NUST MISIS, Almalyk Branch, Almalyk, Uzbekistan
E. S. Nabiev, Cand. Eng., Associate Prof., Dept. of Metallurgy of Ferrous, Non-Ferrous, and Rare Metals, e-mail: nes.2406@mail.ru
S. R. Khudoyarov, Dr. Eng., Associate Prof., Deputy Director, e-mail: suleyman0677@yandex.ru
M. Z. Ubaydullaev, Assistant, Dept. of Metallurgy of Ferrous, Non-Ferrous, and Rare Metals, e-mail: muzacamper@gmail.com
E. I. Ruklinskaya, Assistant, Dept. of Metallurgy of Ferrous, Non-Ferrous, and Rare Metals, e-mail: ruklinskayaelena97@yandex.ru

This paper presents the results of a study on the influence of modifiers on the microstructure, wear resistance, and impact toughness of chromium-molybdenum steel used at JSC Almalyk Mining and Metallurgical Plant for the manufacture of cast parts for mining machinery and processing equipment. The study involved modified samples of 35KhML steel. Vanadium, molybdenum, and aluminum-calcium ferrovanadium nanopowders were used as modifiers. It was established that the optimal result for all studied parameters is achieved with modification with molybdenum nanopowder. This demonstrates the high efficiency of molybdenum as a nanomodifier, promoting the formation of a finely dispersed structure with a uniform distribution of carbides. However, from the standpoint of the technical and economic feasibility of producing modified chromium-molybdenum steel, the use of a complex Fe-V-Al-Ca modifier appears promising, providing an acceptable level of properties at significantly lower unit costs. The formation of stable vanadium carbonitrides and modified non-metallic inclusions under the influence of calcium and aluminum creates conditions for the formation of favorable structures, which facilitates the effective dissipation of impact energy and prevents the development of brittle cracks. The introduction of modifiers has been shown to refine and thin dendrites, promoting their more uniform distribution within the structure compared to the unmodified state. Annealed modified steel has a fine-grained structure with predominantly elongated ferrite grains. After quenching and tempering, the modified steel acquires a sorbitic structure. The results obtained can serve as a basis for the development of high-quality chromium-molybdenum steels used for the manufacture of cast articles.

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