Browsing by Author "Nosko, Olha A."

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    08пс Steel Structure and Properties as a Result of Rolling in the Subcritical Temperature Range
    (CPN Publishing Group; Scientific Publishing Center “Sci-conf.com.ua”, 2024) Kotova, Tetiana V.; Nosko, Olha A.; Aiupova, Tetiana A.
    ENG: The 08пс steel structure and properties formation after rolling at subcritical temperatures with air cooling are studied. The development differs in the temperatures of the beginning and end of rolling, as well as the cooling rate in the post-deformation period. It allows to expand theoretical ideas about the patterns of 08пс deformed steel structure formation. The results of the investigation can be applied in determining rational processing modes, which involve rolling at subcritical temperatures, to increase the complex metal properties and obtain high-quality parts by cold stamping.
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    Influence of Physico-Chemical Processing in Solid and Liquid States on Hypereutectic AlSi18(B-Sn) Alloy Structure and Properties
    (Харківський національний автомобільно-дорожній університет, Україна, 2023) Aiupov, Oleksandr; Nosko, Olha A.; Aiupova, Tetyana A.; Kupchinska, Alina
    ENG: The peculiarities of AK18 alloy (B-Sn) structure formation, mechanical properties, friction and wear parameters formation depending on the regimes of physical and chemical melt processing and thermocycling in the solid state have been established. Observed structural changes (the β-Si and eutectics ratio, the primary and eutectic β-Si crystals shape and size, eutectics differentiation increasing, the pseudoprimary aluminum solid solution (α-A1) dendrites appearance provide an improvement in the complex of mechanical properties and a reduction in wear friction parameters. The obtained experimental data allow to recommend a complex treatment "hydrogen treatment for 40 min + thermal cycling in the solid state at 475-485°C for 5 cycles" to improve the complex of mechanical properties and reduce the wear friction parameters.
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    Regulations of the Formation of Bainetic Component Matrix in Economy Alloyed Chromo-Manganese Alloys
    (Prydniprovska State Academy of Civil Engineering and Architecture, Dnipro, 2023) Pohrebna, N. E.; Nosko, Olha A.; Aiupova, Tetiana A.; Hrebenieva, А. V.; Aiupov, O. A.
    ENG: Purpose. The purpose of the investigation is to establish the regularities of the kinetics of supercooled austenite decomposition in the bainite temperature range (400−200 °C) in chromium-manganese cast iron for the development of thermal hardening regimes that increase the service life of products. Methodology. The object of the study are samples of research and industrial smelting of chrome-manganese cast iron containing 3,1 % carbon, 13,1 % chromium, and 15,75 % manganese. The study of the supercooled austenite decomposition kinetics was carried out by the dilatometric method in the temperature range of 400−200 °C, the study of the microstructure, phase composition, as well as the measurement of microhardness and hardness was carried out according to standard methods. Scientific novelty. The peculiarities of the supercooled austenite decomposition kinetics in the bainite temperature range (400−200 °С) in chromium-manganese cast iron were determined, the structure of the cast iron after aging consists of eutectic carbides Me (Cr, Mn, Fe)7C3, products of austenite decomposition, secondary carbides Me (Cr, Mn, Fe)7C3, Me (Cr, Mn, Fe)3C, as well as untransformed austenite in the amount of 70...75 %. The maximum hardness of the experimental cast iron was established during isothermal exposure at 350 °C for 35 hours. Practical value. The established regularities of the chromium-manganese cast iron structure formation and the determined and optimized temperature-time intervals of the supercooled austenite isothermal decomposition in cast iron are the basis for the development of heat treatment regimes to increase the strength, wear resistance of the material and the service life of its products.
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    Structure and Properties Evolution of the Al-Cu-Mg Alloy during the "Twin-Roll Casting – Hot Deformation – Heat Treatment" Technological Process
    (Kharkov National Automobile and Highway University, Kharkiv, 2024) Nohovitsyn, Oleksii V.; Pryhunova, Adel G.; Aiupova, Tetyana A.; Nosko, Olha A.; Volyniuk, Diana A.
    ENG: The influence of hot deformation and heat treatment on the wide solidification range 2024 alloy twin-rolled cast sheet billets structure and properties evolution at all stages of the technological process was studied. The maximum strength at a reduction ε = 50 % (ζB ≈ 450 MPa), and an increase in ductility with the degree of deformation (from 0–2 % in the cast state to 20–22 % after rolling and heat treatment) were established. The resulting mechanical properties of the 2024 alloy strip exceed existing analogs and standard requirements.
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    Transition from Engineering Strain to the True Strain in Analytical Description of Metals Hardening
    (Prydniprovska State Academy of Civil Engineering and Architecture, Dnipro, 2021) Dolzhanskyi, A. M.; Ayupova, T. A.; Nosko, Olha A.; Rybkin, O. P.; Ayupov, О. А.
    ENG: Purpose of the work is related with the impossibility of correctly estimating the strain hardening of metals (alloys) in the area of their large total deformations due to absence of additivity in the traditionally used value of engineering strain , its nonlinear change in the area of large values, and absence of data in the technical literature Hall-Petch coefficient Ai for logarithmic true deformations, which led to the task of correct transition from the values of the engineering strain 0 <  < 50...60 % to the value of the true logarithmic strainn 0 <  < 1...3. Methodology. The theoretical analysis of the regularities of deformation hardening of metals (alloys) from the engineering strain is carried out, the transition from engineering to logarithmic ("true") strain of metals (alloys) by analytical representation of metal hardening graphs as a function of logarithmic (true) strain. in contrast to the degree of engineering strain is presented. Originality. Analytical expressions are presented that allow the use of known theoretical data on the strain hardening of metals (alloys) at small (50...60 %) total engineering strains  during cold pressure treatment to transition to logarithmic (true) strain  with large total deformations. Practical value. The obtained mathematical expressions allow to use the accumulated in the technical literature experimental data on the hardening of metals and alloys with small engineering strains in the processes of cold processing of metals (alloys) by pressure to determine the hardening with large total logarithmic (true) strains. These data can also be used to solve metallophysical problems of metal processing by pressure associated with large total compressions.