Факультет якості та інженерії матеріалів (ДМетІ) <br> Дніпровський металургійний інститут (ДМетІ)

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UK: Факультет якості та інженерії матеріалів (ДМетІ)
Дніпровський металургійний інститут (ДМетІ) EN: Faculty of Quality and Engineering of Materials (DMetI)
Dnipro Metallurgical Institute

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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.
Application of Dimensional Analysis for Stable Dry Drawing Process Designing
(Інститут металофізики ім. Г. В. Курдюмова НАН України, Київ; Видавничий дім "Академперіодика", 2022) Dolzhanskiy, Anatoliy M.; Mospan, N. M.; Bondarenko, O. A.
ENG: Using the analysis of dimensions, the generalized method of designing rational modes of multiple drawing of wire with dry soapy technological lubricant is improved theoretically and experimentally, taking into account the friction mode in the drawers, other process parameters and determining the acceptable multiplicity of metal flow deformation in the mill. An algorithm is developed for calculating the rational number of rods passes through the dies during flow drawing, the use of which allows, in its implementation in practice, to ensure the stability of the technological process with the absence of wire breaks with the minimum necessary (optimal) number of metal deformation cycles and the corresponding energy consumption. The obtained results are consistent with the practice of industrial drawing with the use of dry technological lubricants on a soap base and can be used in the development of new ones and in checking the rationality of existing technological drawing processes. In the future, it is advisable to develop a program for automatic calculation according to the above algorithm for the rational number of passes during dry drawing, as well as use the presented approach to expand the initial statistical database, taking into account the properties of other steel grades that are deformed in the processes of dry and wet drawing.
Assessing Criteria for Casting and Deformation Suitability of Metals and Alloys
(Dnipro University of Technology, Dnipro, 2025) Kimstach, Tetiana V.; Uzlov, Kostiantyn I.; Bilyi, Oleksandr P.; Mazorchuk, Volodymyr F.; Repyakh, Serhii I.
ENG: Purpose. Based on existing criteria for predicting the suitability of metals and their alloys for manufacturing products from them by deformation or casting analysis develop a set of dimensionless parametric criteria and their quantitative scales. Their using will allow increasing the predicting accuracy of metals and alloys for their processing by pressure or casting suitability and feasibility. Methodology. The work uses phenomenological approach to systematic analysis results of metals and alloys mechanical and individual casting properties interpreting under uncertainty conditions, drawing on literature reference data, expert evaluation data and the authors’ own research results. The authors’ own data have been obtained experimentally using standard methods for mechanical properties determining and due to original authors’ method for technical purity metals and alloys based on them cast samples values of their absolutely hindered linear shrinkage determination during casting. Findings. The authors first proposed parametric dimensionless criteria and scales to them (criteria groups). Their application allows one, through such groups combinations, to assess suitability of any alloy or metal for its use possibility for products manufacturing by casting and/or pressure processing. Originality. For the first time dimensionless parametric criteria have been developed and proposed for use at initial stages of new alloys or technologies elaboration for products from them manufacturing as well as their quantitative scales for preliminary assessment (prognosis) of alloys processing feasibility by pressure or casting, regardless of their type and method. Practical value. Developed criteria and their quantitative scales using will allow alloys developers and specialized enterprises employees to save time and expenses both for alloy elaboration and for its implementation into production.
Comparative Analysis of Technologies for the Production of Hardened Steel Products
(Український державний університет науки і технологій; Університет Аалто Гельсінкі, Фінляндія, 2021) Perchun, Halyna
ENG: Comparative analysis of the known technologies for manufacturing hardened steel products using the methods of heat hardening and the methods of thermomechanical hardening shows that the developed technology favourably differs from the others by using only one type of hardening – deformation, which gives better logistics and ecology due to exclusion of the technological operations of high-temperature heating and rapid cooling; reduces the price of the billet, since the cold deformation does not require alloying. In the known methods of hardening of steel products, the corresponding structural state is formed most often by the heat treatments leading to various phase and structural transformations. At the same time, during operation these products are subjected primarily to deformation effect. In the products manufactured by the new technology, their structural state is formed by the deformation effect, i.e. effect of the same type as during operation. This makes it possible to state that their operational reliability is higher, including under the cyclic loading.
Determination of Particular Relative Reduction in Cold Rolling of Thin and Extra Thin Strips to Implement the Process with the Least Force
(National Academy of Sciences of Ukraine, Publishing House Akademperiodyka, 2022) Vasilev, Ya. D.; Samokish, D. N.; Bondarenko, Oksana A.; Mospan, N. V.
ENG: Introduction. It has been theoretically established and experimentally confirmed that the elastic deformations of rolls and strips in cold rolling have a significant and, in the case of thin rod rolling, a crucial effect on all process parameters. Problem Statement. The influence of the elastic-plastic interaction of a thin strip with rolls, the tension, the temperature and rate of deformation, and the strength of strip material shall be taken into account for developing a modern theory of longitudinal cold rolling. Purpose. Modeling and forecasting the parameters of cold rolling of thin and extra thin strips. Materials and Methods. To solve this problem, the conditions of rolling strips made of 08kp steel with different degrees of preliminary metal hardening, which reflected the features and regularities of hardening the strip material in the multicellular state line, have been modeled. The partial relative reductions vary within 0.02—0.35, with the initial data corresponding to the most characteristic conditions of cold rolling of thin and extra thin steel strips on operating mills taken. Results. The quantitative data on the influence of the strip thickness, at the entrance to the deformation zone, partial and preliminary relative reduction during cold rolling on the process conditions with the least force. For the first time, the conditions and range of partial relative reductions for the cold rolling process of thin and extra thin strips with the least force have been determined. It has been established that in the case of cold rolling of thin and extra thin strips made of unriveted and pre-hardened steel, varying partial relative reductions within the range from 0.1 to 0.30—0.35 provides the realization of process with the least force. Conclusions. The implementation of cold rolling process with the least force is advantageous in terms of energy saving and manufacturability, as it allows reducing the specific consumption of electricity and expanding the range of cold rolling mills for smaller thicknesses of rolling strips and indicates the need to determine conditions for such a process.
Determination of the Deformation Parameters of the Steel Reinforcing Phase inside the Aluminum Matrix during Hot Rolling
(Dnipro University of Technology, Dnipro, Ukraine, 2022) Nosko, Maxim I.; Konovodov, Dmytro V.; Samsonenko, Andrii A.; Bobukh, Oleksandr S.
ENG: Purpose. Comparison of deformation parameters during rolling of reinforced composites based on aluminum alloy using braided and expanded steel meshes as a reinforcing phase. Methodology. An experimental study on the effect of pressure on the deformation of the reinforcing phase during rolling of aluminum composites is carried out. A wire mesh and expanded mesh made of stainless steel was used as a reinforcing phase. The effect of deformation on the change in the lattice angle of the reinforcing phase is investigated. Findings. In this work, experimental data on the parameters of deformation of the wire mesh and expanded mesh are obtained. A comparison is made of the shape change in such grids under hot rolling conditions between two aluminum plates, which play the role of a matrix. It is found that the elongation coefficients of the lattice for the experiment with a wire mesh μc is equal to 1.68–2.3, which is greater than the coefficient of elongation of the lattice in the expanded mesh of 1.55–2.2. Therefore, expanded sheets make the best reinforcing layer for aluminumbased composites produced by the rollbonding process. Expanded mesh also reduces the risk of rupture at the intersection of wires. Originality. In the work, for the first time, a comparison of the deformation parameters during roll bonding of composites based on an aluminum alloy, reinforced with a braided and expanded steel mesh, has been given. Obtaining composite materials by means of hot roll bonding requires an understanding of the flow of composite components during deformation and their influence on each other. These peculiarities have not been studied sufficiently. Currently, there is no reliable method for predicting the behavior of the material of a solid reinforcing phase of various shapes inside a composite. Practical value. Advantages of using an expanded steel mesh for reinforcing aluminumbased composites have been confirmed. Scientific results can be used to refine calculating methods for metal flow at high hydrostatic pressure with variable components of the stress tensor and the major stresses.
Determining the Thermally-Stressed State of Motor-Driven Bowls for Transporting Liquid Slag
(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, 2024) Povorotnii, Viktor V.; Shcherbyna, Iryna V.; Zdanevych, Serhiі V.; Diachenko, Nina K.; Kimstach, Tetiana V.; Solonenko, Lyudmila I.; Usenko, Ruslan V.
ENG: Slag bowls were chosen as the object of research, as important components of blast furnace, steelmaking, and ferroalloy shops of metallurgical enterprises. The main problem of operation of any slag trucks is their limited durability and frequent destruction of slag bowls. The reason for these problems is changes in the shape of the bowls during operation, manifested in the formation of narrowing places in the area of the support ring – for rail-mounted bowls, destruction of supporting pins – for rail-mounted slag trucks, or cracks in the walls. Those defects appear as a result of cyclic thermal effects of liquid slag on the bowl. Based on the results of computer simulation, it was established that the main role in the destruction of the support pins of motor-driven slag bowls belongs to temperature changes. The temperature stresses arising in the bowl are localized in the area of the slag mirror (200–250 MPa for 25L steel, 280–350 MPa for 30HML steel). The results provide grounds for improving the presented slag bowl to reduce temperature stresses in its walls and structures of the supporting trunnions. The results reported here are explained by the fact that with uneven heating of elastic bodies, temperature stresses appear, which, under certain configurations of temperature loads, lead to the destruction of structures. The findings from these studies are recommended to be used at enterprises for the design and manufacture of slag bowls, as information on the localization of dangerous places of the structure. In addition, the data presented here could be useful for metallurgical enterprises for detailed technical diagnosis of bowls in their dangerous places.
Development Features and Principles of Blockchain Technologies and Real Options as the Main Components of the Digital Economy
(Springer, Singapore, 2022) Vazov, Radostin; Shvachych, Gennady; Moroz, Boris; Kabak, Leonid; Kozenkova, Vladyslava; Karpova, Tetiana P.; Busygin, Volodymyr
ENG: The paper shows that the digital economy reveals a huge range of opportunities for various enterprises. It noted its strengths: costs reduction, in-creasing the level of transactions’ security and transparency, close focus of vari-ous sectors of the economy. In this regard, for a clear and definite understanding of the problems under consideration, the authors introduced the definition of the digital economy, digital technologies in the economy, and “end-to-end” digital technologies in the economy. The authors’ proposed approach allowed concluding that the digital econo-my term is distinguished by several subtleties associated with insufficient knowledge, understanding of technical implementation, and flexibility. The research aims at revealing the development features and principles of the main components of the digital economy: distributed ledger technology (blockchain) and option technologies. The paper shows that blockchain technology, as a decentralized data ledger, is the most discussed and relevant topic in the development of the digital econ-omy. Its strengths are analyzed, such as cost reduction, increased security and transaction transparency affecting various sectors of the economy. The conducted research exposes the essence of the main provisions of tac-tics and strategies when solving the problem of options pricing. At the same time, there is presented a new classification of options contracts allowing to de-termine the ways of their application and development. Whereas, the analysis of the problem of options contracts pricing demonstrated the relevance of new mathematical methods developed for their reliable and accurate evaluation. The paper shows that at present, interest in the concept and technique of re-al options application has significantly increased; as they draw attention as a po-tentially essential tool for evaluation and improving an enterprise development strategy.
Development of a Model for Calculating Changes in K76f Rail Steel Temperature to Determine the Heat Treatment Parameters
(National Academy of Sciences of Ukraine, 2021) Babachenko, Oleksandr; Kononenko, Ganna; Podolskyi, Rostyslav
ENG: Introduction. The conditions of operation of the railways of Ukraine and the prospects for their entry into the international system of transport corridors require the development and modernization of railway tracks, including rails. Problem Statement. Given the necessity to ensure the main operational parameter of the rails (wear resistance), regulatory and technical documents standardize hardness. The most progressive European standard EN 13674-1-2011 establishes that the hardness of the rail head at a depth of 20 mm shall be, at least, 321 HB, while STU 4344:2004 requires, at least, 321 HB at a depth of 11 mm. At the same time, according to EN 13674-12011, the rail surface hardness without the formation of needle structures shall be, at least, 405 HB. Purpose. To determine the possibility of achieving hardness without needle structures for rail head made of steel 0,80% C, 0,25% Si, 0,97% Mn, 0,055% V (hereinafter referred to as K76F), which complies with the world requirements, based on the calcination experiment and calculations with the use of the model; to determine the rational cooling rate for K76F steel during heat treatment. Materials and Мethods. K76F rail steel with 0.80% C, 0.25% Si, 0.97% Mn, 0.055% V. Techniques: metallographic studies, hardness measurements, determination of calcination by end quenching, modeling by means of mathematical calculation with the use of QForm heat treatment software package. Results. The change in temperature, the formation of structure and hardness across the section of a K76F steel sample for calcination tests according to GOST5657 has been modeled. The changes in the hardness and microstructure has been experimentally established, depending on the distance to the heat sink surface; the cooling rate in the points where the hardness meets the requirements of EN 13674-1-2011 for rails has been determined. Conclusions. The analysis of the model has shown a high accuracy of the model and the convergence of the experimental results with the calculated ones. It has been established that the requirements of EN 13674-1-2011 can be achieved up to a hardness of 405 HB without the formation of needle structures on steel that meets the chemical composition of K76F according to DSTU 4344: 2004.
Effect of Fullerene-Like Nanoparticles on the Tribological Properties of Industrial Lubricants for Steel Rolling
(Khmelnytskyi National University, 2022) Kartun, I. M.; Remez, Oleg A.; Haidai, O. O.; Spaska, O. A.; Yanchenko, O. B.; Pyliavsky, V. S.; Polunkin, Ye.V.
ENG: The paper shows the results of studying the possibility of using fullerene-like nanoparticles as a lubricating additive in the composition of technological lubricant MT-216 M. The lubricity properties were evaluated on a laboratory rolling mill DUO-180 during cold rolling of strips of steel 08kp. The rolling force, the coefficient of friction in the deformation zone were measured, the values of the elongation coefficient and the parameter reflecting the costs of the rolling force per unit deformation of the metal were calculated.
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.
Features of the Ferrite-Bainite Structure Low-Alloy Low-Carbon Steel after Heat Hardening and Subsequent Tempering
(Prydniprovska State Akademy of Civil Engineering and Architecture, 2021) Deineko, Leonid M.; Borysenko, A. Yu.; Taranenko, A. A.; Zaitseva, T. O.; Romanova, Nataliia Serhiivna
ENG: Problem statement. In recent decades, there has been a tendency to increase the mechanical properties of low-carbon, low-alloyed steel plate iron by using controlled rolling or hardening heat treatment of finished steel parts. At the same time, for welded parts, the most suitable is a metal having a ferrite-bainite (or bainite) structure. The work investigated the features of the ferrite-bainite structure of low-carbon and low-alloyed steel 15ХСНД for the production of connecting pipeline parts. Purpose of the article. To establish the laws of formation of a ferritic-bainitic structure in low-carbon low-alloy steels depending on the parameters of heat treatment. Determine the effect of heat treatment parameters on the properties of the connecting parts of pipelines made of these steels. Conclusion. The regularities of the influence of heat treatment parameters on the structure, mechanical properties and topography of fractures of impact samples of 15ХСНД steel with a ferrite-bainitic structure are established.
Features of Using the Distance Learning Model
(Ukrainian State University of Science and Technologies; Aalto University Helsinki, Finland, 2021) Shvachych, Gennady G.; Khokhlova, Tetiana S.; Stupak, Yurii O.; Moroz, Boris; Kabak, Leonid
ENG: Purpose. To analyze models of distance learning (DL) that have been implemented in the world and have shown effectiveness in order to determine promising directions for the development of DL: testing, educational research, contextual learning, mobile learning, development of social networks, application of mobile educational games, implementation of mobile voice content with interactive assessment etc. Methodology. Literature review of open access information sources. Findings. It has been determined that special attention should be paid to the technologies of educational institutions, in which it is possible to involve highly qualified teachers in reading lectures; there is a significant saving of teachers' time; there is a possibility of increasing the amount of material presented within the budget allocated for regular classroom activities in the curriculum. Originality. It consists in a certain set of criteria, based on the analysis, which are necessary and sufficient to achieve the final goal. Practical value. The methods of selection of educational tools make it possible to increase the effectiveness of the educational process, make it attractive and exciting for students and motivate them to an active educational process always and everywhere, which allows students to receive a quality education.
Forecast and Control of Structure and Properties of Ultra-Low-Carbon Steels
(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2021) Koval, Yu. M.; Kutsova, Valentyna Zynoviivna; Kotova, T. V.; Kovzel, M. A.
ENG: Concentration ranges of elements’ containing to optimize the composition of 01YuTA, 01YuT steels and to ensure the required set of rolled products properties are obtained using the method of physico-chemical modelling. The effect of rolling deformation modes in the ferritic temperature range on the formation of the structure and on the properties of ultra-low-carbon steel is investigated. The obtained data can be used to control the processes of structure formation and to establish rational technological regimes for the processing of rolled sheet material for automobile and machine-building enterprises.
In situ Composites: A Review
(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine (IMP NASU), Kyiv, 2021) Movchan, O.  V.; Chornoivanenko, Kateryna O.
ENG: The review of the works on the fabrication-technology studies, patterns of structure formation, and properties of in situ composites is presented. The main advantage of in situ (natural) composites is the thermodynamic stability of their composition and the coherence (conjugation) of the lattices of the contacting phases. All these ones provide the composite with a high level of the physical and mechanical properties. As shown, composite materials of this type are formed in the process of directed phase transformations, such as eutectic crystallization, eutectoid decomposition, etc., caused by a temperature gradient, as well as a result of diffusional changes in composition. The conditions for the growth of in situ composites are formulated. The mechanisms of growth of composite structures of the eutectic type are considered. The factors influencing on the morphology of structures of the eutectic type are indicated. The considered technological methods make it possible to obtain materials with predetermined properties, in which the size, volumetric composition, and spatial arrangement of phases are characteristic of in situ composites. The paper provides a large number of examples of in situ composites: from low-melting Bi-based alloys to refractory eutectics based on Mo and W (Bi–MnBi, Cd–Zn, Al–Al3Ni, Al–Al4La, Al–Al10CaFe2, Al–Al9FeNi, Al–Al3Zr, Al–Al3Sc, Au–Co, Si–TaSi2, Cr–HfC, Cr–ZrC, Cr–NbC, Cr–NbC, Cr–TaC, Nb–Nb5Si3, Mo–ZrC, Mo–HfC, W–TiC, W–ZrC, W–HfC, etc.). Processes and aspects of structure formation are considered. The influence of additional doping on the structure and properties of composite materials of the eutectic type of binary systems, as well as the features of the structure formation of ternary colonies in the composite are considered.
Influence of Ice Structure on Vitability of Frozen Sand-Water and Sand-Clay Mixtures
(Dnipro University of Technology, Dnipro, Ukraine, 2024) Solonenko, L. I.; Uzlov, Kostiantyn I.; Kimstach, Tetiana V.; Mianovska, Ya. V.; Yakymenko, D. Yu.
ENG: Purpose. To establish influence regularity of sand, water and clay preparation conditions on vitability of frozen mixtures made from combinations of these components and to increase the castings quality in foundries, as well as to improve technologies for artificial freezing of soils for underground constructions. Methodology. In this research, sand, clay, and water are used. Ice quality is estimated visually after water freezing at -15 °C in glass tubes. Frozen mixtures’ vitability at -15 °C is studied on beam-type samples. As indicators of survivability, the time to 1 mm bending of samples on supports and the time to their destruction are accepted. The time is recorded with a stopwatch, the temperature with an alcohol thermometer, the mass with electronic scales and the deflection arrow with a clock-type indicator. Findings. The presence and amount of water-soluble impurities in rare water significantly influence the nature, size and distribution of gas bubbles in ice, as well as frozen sand-water mixtures vitability. Frozen mixtures’ survivability increases with water content in them increasing, and, for sand  water mixtures, survivability is maximum if ice has a homogeneous structure. Among mixtures with clays, the mixture with non-swollen kaolin clay has the greatest vitability. Regarding survivability, recommendations for manufacturing products from frozen foundry mixtures have been developed. Originality. For the first time, deformation change kinetics (bending arrows) under the influence of beam-type samples’ self-mass from mixtures of quartz sand and water and quartz sand, clay and water frozen at -15 °C, which have been previously prepared in different ways, have been investigated. Insights into the influence of various factors and ice quality on the vitability of frozen mixtures have been further developed. Practical value. The obtained results can be useful for expanding ideas about natural frozen soils’ behavior during their cyclic temperature changes, soils artificially frozen during mine shafts elaboration, escalators’ and junctions’ tunnels, etc. when constructing subways. In foundries, the developed recommendations will reduce technological losses and will improve casting quality made using frozen casting molds and cores from sand-water or sand-clay-water mixtures, castings’ patterns and their pouring systems from sand-water mixtures.
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.
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.
Influence of Surfactants on Copper-CNTs Electrodeposition
(Lviv Polytechnic National University, Lviv, Ukraine, 2021) Roslyk, Iryna; Stovpchenko, Ganna; Galchenko, Galyna
ENG: Influence of different types of surfactants on electrodeposition of copper- and carbon-bearing (graphite, carbon nanotubes (CNTs)) composite powder has been experimentally investigated. The size of powder particles decreased, and corrosion resistance increased when surfactants were added. Addition of cationic surfactant CTAB to the electrolyte with simultaneous ultrasonic treatment for CNTs dispersion gives maximum effect.
Kinetics of Quartz Sand and Its Mixtures Drying by Microwave Radiation
(Dnipro University of Technology, 2021) Solonenko, Lyudmila I.; Repiakh, Serhii I.; Uzlov, Kostiantyn I.; Mamuzich, I.; Kimstach, Tetiana V.; Bilyi, Oleksandr P.
ENG: Purpose. Kinetics research and description of drying by microwave radiation mechanism development of quartz sand and its mixes with sodium silicate in limited quantity of water steam medium. Methodology. Distilled water, sodium silicate solute and quartz sand have been used in this research. Study has been performed on sand samples weighing 200 g. Mixtures drying and structuring have been performed by microwave radiation with power of 700W with frequency of 2.45 GHz in air and in saturated water weighing 1 g steam medium. Accuracy of temperature measurement is 1, mass is 0.02 g. Realized in this investigation drying kinetics has been specified as specimen weight change dependence and moisture evaporation from this mixture rate vs. drying duration. Dependencies have been built on the results of video recording and corresponding chrono-gravimetric measurements data digitalization. Mixtures during heating by microwave radiation temperature changes registration has been performed with an interval of 1560 s. Samples average heating rate has been estimated by calculation based on results in their temperature change determination during first 2 minutes of heating with microwave radiation. Findings. For the first time, microwave drying kinetics of quartz sand and its mixtures with sodium silicate in limited water medium (structured by SMS-process) has been studied. For the first time, based on SMS-process material balance, analytical dependence has been developed. This dependence application allows sand-sodium-silicate mixture structured by SMS-process maximum mass to calculate when using sodium silicate solute (silicate module 2.83.0) for quartz sand cladding and 1 g of saturated water steam for mixture structuring. It has been established that when mixtures structuring according to SMS-process water extraction from them takes place in three stages at ~100, 100108 and at 125138. Maximum appropriate heating temperature of sand-sodium-silicate mixture during structuring by SMS-process has been recommended as ~125. Exceeding of specified temperature leads to hydrated water from mixture releasing in steam form and its condensation on colder working surface of model-rod rigging. Resulting condensate leads to mixture restructuring in contact with equipment places and, accordingly, sharp quality deterioration in prepared molds and rods. For manufactured molds and rods quality stabilization, it has been recommended to pre-dry the quartz sand cladded with sodium silicate solute in microwave field for at least 3 minutes before structuring according to SMS-process. Originality. For the first time, data on drying kinetics has been obtained and quartz sand and its mixtures with sodium silicate in limited water steam medium microwave drying mechanism description has been developed. Influence of number of SMS-process basic parameters on structured quartz sand weight regularities has been established. Practical value. Research results will be useful in terms of ideas expanding about the processes that accompany granular materials drying, as well as in technologies and equipment for drying and structuring fine-grained dielectric materials and their mixtures development, creating new capillary-porous media, etc. under microwave radiation influence.