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Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/35393
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Документ Increase of operational properties of tools and machine parts nitriding the powder mixture(2019) Kostyk, V. O.; Kostyk, K. O.; Kovalov, V. D.; Turmanidze, R.; Dašić, P.The effect of diffusion layers and alloying elements on surface hardness, microcoarseness, and wear resistance of hardened tool steels in a nitrogen-containing medium is Studied. The experiments showed that nitriding in the powder mixture strengthens the surface layers in 2–3.5 times without reducing the volume strength of the material in question, which contributes to the preservation of high structural strength of tools and machine parts. It was found that nitriding in the dispersed powder mixture provides increased wear resistance of 1.3–2.5 times of steel, which can significantly improve the reliability and durability of products. Mathematical models of wear resistance of the investigated steels after the proposed hardening technology of nitriding are obtained.Документ Surface hardening of steel parts(Одеський національний політехнічний університет, 2017) Idan, Alaa Fadhil І; Akimov, O. V.; Kostyk, K. O.Development of new resource-saving and costeffective technologies of combined hardening of steel parts with a significant reduction of the process duration is an important and urgent task. Aim: The aim of the work is to create a technology for combined toughening of steel parts to provide high operational properties of the steel surface layer by intensifying the nitriding process through the laser pre-treatment of steel products. Materials and Methods: Materials for study are types of steels 40, 40Cr and 38Cr2MoAl. Laser treatment of steel was performed at the LATUS-31 installation. Nitriding carried out in the environment of fine nitrogen-containing substance with activators at a temperature of 530…560 ºC during 2…3 hours. The nitriding process was carried out in the closed atmosphere in the chamber furnace without application of the protective atmospheres. Influence of laser pre-treatment and final nitriding on structure, thickness, phase structure, microhardness of surface layers of steel samples has been investigated. Results: It is shown that preliminary hardening by laser increases surface hardness in 0.88…1.15 times after nitriding, depending on brand of steel and speed of a laser beam movement, in comparison with steel nitriding in similar conditions. The combined treatment promotes significant increase in the strengthened layer – up to 0.49 mm for 40 steel type, up to 0.55 mm for 40Cr steel type and up to 0.65 mm for 38Cr2MoAl steel type.