Browsing by Author "Vakulenko, Ihor A."
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Item The Effect of Stress Pulses on the Cyclic Endurance of Steel Axle Wheel-Set(Nevsehir Haci Bektas Veli University, Cappadocia, Nevsehir, Turkey, 2019) Vakulenko, Ihor A.; Bülent, Kurt; Raksha, Serhii V.; Askerov, Hangardas; Hryshchenko, Mykola A.ENG: For different temperature and speed deformation conditions, the nature of the increase in the number of defects in the crystal structure and the achieved complex of properties are due to the peculiarities of the internal structure of the metallic material. Compared with unidirectional static loading, the violation of the monotonous nature of the effective stress is accompanied by qualitative changes in the internal structure of metals and alloys. Thus, the pulsating nature of the acting stresses in case of fatigue, depending on the degree of cyclic overload per cycle, can lead to significant changes in the development of the processes accumulation and redistribution of defects in the crystal structure and, above all, dislocations. Based on this, the rate of accumulation of dislocations per loading cycle can be considered as one factor that will allow the development of measures to increase the cyclic endurance of metallic materials during fatigue. Compared to thermal technologies, treatments that are based on the use of short stresses pulses for moving defects in a crystal structure have gained some fame. In addition to sufficiently strong magnetic fields or high-power pulses of electric current, treatments based on mechanical effects on the metal can be used.Item Influence of Substructure Strengthening of Law-Carbon Steel on the Arcing Process(WRTYS, Kyiv, 2017) Vakulenko, Ihor A.; Plitchenko, Sergey; Nadezhdin, Yurii L.; Kirienko, Yu. D.EN: For the arcs of forward and reverse polarities there found extreme dependences value of electric current on cold drawing with a maximum at 60% strain. In order to explain the nature of the dependencies of value of electric current on cold drawing the equation for estimating electric current was used with the replacement of surface tension coefficient for the surface tension coefficient of the ferrite of low-carbon steel. Taking into account the fact that as cold drawing increases from 17 to 80% the size of cells is reduced by 30%, the value surface tension coefficient of the ferrite was increased approximately by 1.5 times. After substituting surface tension coefficient of the ferrite in the ratio it has been found sufficiently good agreement of value of electric current with the experimental values of the welding current for reductions of up to 60%. Increase of cold drawing over 60% has led to an increase in differences up to 14 – 22% between value of electric current and the obtained experimental data.Item Plasma Case Hardening of Wear-Resistant High-Chromium Cast Iron(Springer New York Consultants Bureau, 2017) Efremenko, Vasiliy G.; Chabak, Yu. G.; Karantzalis, A. E.; Lekatou, A.; Vakulenko, Ihor A.; Mazur, V. A.; Fedun, V. I.EN: The effect of plasma parameters on the case hardening of wear-resistant high-chromium cast iron in different structural condition is studied. Correlation relations were established between the initial and finite microstructure of the surface layer formed after plasma hardening at different heating rates. Microhardness profiles over the cross-section of the modified layer are structurally substantiated. Recommendations for optimizing the complex bulk-surface cast iron treatment conditions are given.Item The Transformation of Structure Steel with Thermal Strengthening of the Disk Railway Wheel(Karabuk University, Karabuk, Turkey, 2019) Vakulenko, Ihor A.; Proidak, Svitlana V.; Raksha, Serhii V.; Akay, M.; Cug, Harun; Askerov, KhangardasENG: On the example of the carbon steel, issues of structuring in the process of accelerated cooling are considered. The emerging gradient of structures at different distances from the surface of the heat transfer is presented in the form of a dependence, which is adequate to the effect of the temperature of individual heating during the release of steel after the quenching. It is shown that after the forced cooling is stopped, the increase of distance from the cooling surface accompany higher the tempering temperature of the metal. In the volumes of the metal, the microstructure close to the middle of the disk wheel is formed by the diffusion mechanism.Item Use of Electric Pulse Treatment for Relaxation Internal Stresess(DIA Ltd, Kyiv, 2017) Vakulenko, Ihor A.; Plitchenko, Sergey; Sokirko, V. A.; Nadegdin, Yurii L.; Efremenko, Vasiliy G.EN: The article deals with explanation of the effect redistribution of residual stresses after processing electrical pulses based on aluminum alloy after welding. The results indicate quite significant influence of electrical pulse treatment on both the morphology of alloy structural components and the relation of chemical elements involved in the formation of certain phases alloy. After the welding alloy had the majority of the signs of the cast condition with characteristic plate forms of the eutectic components. The use of EP has led to the quite significant qualitative changes in the internal structure. The globular structures formation indicates a high degree of EP influence on the development of structural change processes. Studying the chemical composition of the phase components was found out that the observed structural changes of alloy as a result of EP first of all may be caused by the redistribution of chemical elements, which form the compounds themselves. After the EP of the welded joint, the alloy hardness increase is accompanied by the decrease in the number of crystal structure defects and coarsening of the coherent scattering regions.Item Сauses of Structural Heterogeneity Low-Carbon Sheet Steel and its Elimination(Nevsehir Hacı Bektaş Veli University, Kızılcahamam, Ankara, Turkey, 2019) Askerov, Khangardas; Cug, Harun; Kurt, Bulent; Vakulenko, Ihor A.; Proydak, Svetlana V.EN: Abstract. Based on the analysis of mechanism development of ferrite recrystallization processes, on example of lowcarbon hot-rolled sheet steel, measures are proposed reduce heterogeneity of structure rolled products. Creating a certain gradient in distribution defects of crystalline structure over the thickness of sheet lowcarbon steel allows after annealing