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Документ Nanodispersed boriding of titanium alloy(Одеський національний політехнічний університет, 2015) Kostyk, K. O.; Kostyk, V. O.The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemical-thermal treatment. Aim: The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. Results: It is established that boriding of paste compounds allows obtaining the surface hardness within 30...29 GPa and with declining to 27...26 GPa in layer to the transition zone (with total thickness up to 110 μm) owing to changes of the layer phase composition where Ti2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30...110 μm) and transition zone (30...190 μm). Conclusions: Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2...3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening.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.Документ Research of influence of gas nitriding duration on formation of diffusion layer of steel 20Kh2N4A(Одеський національний політехнічний університет, 2015) Kostyk, K. O.The research of the gas nitriding process, which allows to obtain a high surface quality of steel parts and has a wide application in mass production, is relevant. Aim of the research is to study the influence of gas nitriding modes on the structure and properties of alloy steel. The research material in this work is steel 20Kh2N4A. Nitriding of the samples is carried out in a shaft furnace at the temperature of 510…530 °C during 35, 40, 46 and 48 h. It is found that the alloy steel 20Kh2N4A preliminary heat treatment before nitriding provides the hardness of products core to 279...321 HV due to the formation of perlitesorta structure with carbides of alloying elements. The results show that increasing the duration of nitriding from 35 to 48 hours at 510…530 °С increases the depth of nitrided layer from 0,35 to 0,55 mm with surface hardness up to 648 MPa at the maximum depth of the layer. The results of this research can be used in industry and research works.