Кафедра обробки металів тиском (ДМетІ)

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http://crust.ust.edu.ua/handle/123456789/14630
UK: Кафедра обробки металів тиском ім. акад. О.П.Чекмарьова (Дніпровський металургійний інститут, ДМетІ) EN: Department of Metal Forming (DMetI)

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Browsing Кафедра обробки металів тиском (ДМетІ) by Author "Frolov, Yaroslav"

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    Estimation of Glass Lubricant Viscosity for Hot Extrusion of Cr-Ni Steel and Ni Alloy Tubes
    (Dnipro University of Technology, 2022) Medvedev, Michael; Shyfrin, Yevgen; Frolov, Yaroslav; Bobukh, Oleksandr
    ENG: Purpose. Estimation of optimal viscosity of a glass lubricant for chromium-nickel steel tube extrusion depending on the deformation resistance, chemical composition of metal and the temperature, degree and rate of deformation. Methodology. To determine the force conditions for tube extrusion, a complex factor of deformation resistance was used, which consists in estimating the value of deformation resistance under the basic process parameters of extrusion plants and its refinement depending on the deviations of heating temperature and wall thickness of billets as well as the degree and rate of deformation from the base conditions. Findings. The dependence of basic values of deformation resistance on the percentage of alloying elements (Ni + Cr) in steels has been found. With the addition of hardening alloying elements (Mo, W, V, Nb) into the alloy steel, its deformation resistance increases in proportion to their percentage. Analytical expressions for calculating the base values of deformation resistance for different extrusion plants have been obtained. Originality. For the first time, the principles governing estimation of the optimal viscosity of glass lubricants based on the chemical composition of steel to be formed, its temperature and the degree and rate of deformation of the blank, thickness of the lubricating layer and geometric dimensions of the tool (die) in hot extrusion of tubes have been established. Practical value. The use of the results of calculation according to the developed method will make it possible to increase the surface quality of tubes manufactured by extrusion and reduce the volume of their subsequent machining.
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    Influence of Solidification Rates and Heat Treatment on the Mechanical Performance and Joinability of the Cast Aluminium Alloy Alsi10mg
    (German Academic Society for Production Engineering (WGP), 2022) Neuser, M.; Grydin, O.; Frolov, Yaroslav; Schaper, Mirko
    ENG: In modern vehicle chassis, multi-material design is implemented to apply the appropriate material for each functionality. In spaceframe technology, both sheet metal and continuous cast are joined to castings at the nodal points of the chassis. Since resistance spot welding is not an option when different materials are joined, research is focusing on mechanical joining methods for multi-material designs. To reduce weight and achieve the required strength, hardenable cast aluminium alloys of the AlSi-system are widely used. Thus, 85–90% of aluminium castings in the automotive industry are comprised of the AlSi-system. Due to the limited weldability, mechanical joining is a suitable process. For this application, various optimisation strategies are required to produce a crack-free joint, as the brittle character of the AlSi alloy poses a challenge. Thus, adapted castings with appropriate ductility are needed. Hence, in this study, the age-hardenable cast aluminium alloy AlSi10Mg is investigated regarding the correlation of the different thicknesses, the microstructural characteristics as well as the resulting mechanical properties. A variation of the thicknesses leads to different solidification rates, which in turn affect the microstructure formation and are decisive for the mechanical properties of the casting as well as the joinability. For the investigation, plates with thicknesses from 2.0 to 4.0 mm, each differing by 0.5 mm, are produced via sand casting. Hence, the overall aim is to evaluate the joinability of AlSi10Mg and derive conclusions concerning the microstructure and mechanical properties.
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    Laser Beam Melting of Functionally Graded Materials with Application-Adapted Tailoring of Magnetic and Mechanical Performance
    (Elsevier, 2021) Andreiev, Anatolii; Hoyer, Kay-Peter; Dula, Dimitri; Hengsbach, Florian; Grydin, Olexandr; Frolov, Yaroslav; Schaper, Mirko
    ENG: The processing of functionally graded materials (FGMs) using laser beam melting (LBM) is a promising technique for increasing the efficiency of conventional machine components, especially for e-mobility. Therefore, the aim of the current study is to prove the manufacturability of tailored mechanical and magnetic properties in a rotor for an electric motor. For this purpose, the design of additively manufactured rotors with application-adapted tailoring of the properties in the same component using FGM was proposed. The first step was to investigate whether the FGM of the components, i.e. soft-magnetic steel for the rotor core and high-strength steel for the rotor shaft ends, are suitable for machining by LBM. Subsequently, multi-material samples of the two investigated steel types with their different arrangement were processed by LBM. Furthermore, post-processing heat treatments and their effects on the microstructure and resulting magnetic properties as well as the mechanical performance of mono- and multi-material samples were analyzed. The combination of LBM and an additional post heat treatment enables both the formation of a good adhesive bond between the two alloys and the desired tailoring of the properties in the FGMs investigated.
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    Roll Bonding of Al-Based Composite Reinforced with C10 Steel Expanded Mesh Inlay
    (MDPI, Switzerland, 2021) Frolov, Yaroslav; Nosko, Maxim; Samsonenko, Andrii A.; Bobukh, Oleksandr; Remez, Oleg
    ENG: The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites. View Full-Text.