Browsing by Author "Solonenko, Liudmyla I."

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Determination of Bronze БрА7К2О1,5Мц0,3 Crystallization Interval Limit Values and Phase Transformations
(Dnipro University of Technology, Dnipro, 2025) Kimstach, Tetiana V.; Uzlov, Kostiantyn I.; Bilyi, Oleksandr P.; Solonenko, Liudmyla I.; Repyakh, Serhii I.
ENG: Phase transformations temperatures, crystallization intervals, etc. are any alloy’s fundamental parameters. Alloys’ casting, technological and operational properties are related to them. Nevertheless, unlike two-component bronzes, such requirements for multi-component structural, non-magnetic, corrosion-resistant bronze БрА7К2О1,5Мц0,3 are absent. Purpose. For Cu-Al-Si-Sn-Mn system bronzes, crystallization intervals quantitative values (liquidus and solidus temperatures, crystallization interval size and solid phase relative share in it) have been established. БрА7К2О1,5Мц0,3 bronze’s alloying components’ synergistic and selective influence on its crystallization interval and relative fluidity indicators changing has been determined. Methodology. Well-known methods and research techniques, including thermography, differential thermal analysis, spectral chemical analysis, images analysis digital method have been used in this work. Bronzes fluidity has been assessed using spiral test. Bronze’s alloying elements’ synergistic and selective influences on its characteristics have been determined using chemical elements ratio in it (KR criterion) and experimental data results processing by Excel computer program. Findings. In bronze БрА7К2О1,5Мц0,3 with KR criterion value rising from 0.35 to 0.84, there increase liquidus, solidus temperatures and crystallization interval from 32 to 49 °C. Bronze’s alloying elements’ (Al, Si, Sn, Mn) synergistic and selective influences on its crystallization interval limit values have been determined. It has been established that conditionally-veritable fluidities of БрА7К3О1,5Мц0,3 and БрА9Ж3Л bronzes are practically the same. For Cu-Al-Si-Sn-Mn system bronzes with KR = 0.35‒2.07, solid phase relative volume fraction (φSP) in crystallization temperature range is 60‒63 %. Originality. For the first time, limiting values and phase transformations for БрА7К2О1,5Мц0,3 bronze’s crystallization interval and alloying elements synergistic and selective influence on these indicators have been determined. Practical value. Based on БрА7К2О1,5Мц0,3 bronze’s chemical composition selected, mathematical models have been proposed for its liquidus and solidus temperatures calculating and for transition from dependences of solid phase t(φSP) volume fraction in crystallization temperature range to temperatures’ absolute values t(φSP). Their use will allow increasing the indicators of foundry and technological parameters accuracy forecasting.
Expanding Technical and Technological Posibilities in the Production of Parts and Tools Using Bronzes
(MM Science Journal, Czech Republic, 2026) Kimstach, Tetiana V.; Panda, Anton; Dyadyura, Kostiantyn; Uzlov, Kostiantyn I.; Solonenko, Liudmyla I.; Repyakh, Sergey I.
ENG: Among the known standardized bronze grades, there are currently no foundry structural bronzes that would simultaneously combine both non-magnetism and corrosion resistance, in particular, in tap water and seawater. The presence of bronze with such a list of preferential properties will allow not only to expand the boundaries of bronzes as a structural material using, but also to provide prospects for increasing and expanding the technical and technological capabilities of new equipment and technologies in the field of shipbuilding, aircraft construction, instrument making, etc. Today, the only bronze with such a list of properties is aluminum bronze BrA7K2O1.5Mts2, in which, nevertheless, corrosion resistance in comparison with known standardized bronze grades has not yet been studied. All bronzes studied in this work, except for bronze BrO6C6C3, are absolutely stable in warm standing tap water with a cyclic change in temperature from 30 to 50 °С. With the exception of BrA9Zh3L bronze brand, all other bronzes studied in the work are stable in warm standing artificial seawater with a daily change in temperature from 30 to 50 °С and on a ten-point scale have the 4th point of corrosion resistance. The greatest corrosion resistance is possessed by bronze BrA7K2O1.5Mts0.3 with a value of KR = 0.47…0.63. Corrosion in samples of BrA7K2O1.5Mts0.3 bronze, which are after their heat treatment and without heat treatment, is equally continuous. Bronze BrA7K2O1.5Mts0.3 without heat treatment in cold standing artificial seawater is more corrosion-resistant if it is cast in a chill mold. At the same time, in all corrosive environments used in the work, the corrosion resistance of bronze BrA7K2O1.5Mts0.3 is more affected by its heat treatment than by in its chemical composition changing. Further development was received by ideas about the corrosion resistance of non-magnetic structural cast aluminum bronzes in tap water and artificial seawater, taking into account the initial state of the bronzes and the corrosive environment condition. For the first time, in comparison with standardized corrosion-resistant bronze grades, data were obtained on the corrosion rate of “as-cast” and heat-treated non-magnetic bronze BrA7K2O1.5Mts0.3 in warm tap water, warm and cold artificial sea water. This will allow making a well-founded choice of bronzes for the operation of products made of them in the environments and conditions used in this work or close to them. This will save time, financial costs and material resources for developers of new machines, assemblies and units to make a rational or optimal technical decision regarding a rational product material.
Freezing in a Refrigerator of Engineering Products from Sand-Water Mixtures
(MM Science Journal, Czech Republic, 2026) Solonenko, Liudmyla I.; Panda, Anton; Dyadyura, Kostiantyn; Repiakh, Sergey I.; Yakimenko, Dmytro
ENG: The work establishes a number of features regarding the mechanics of freezing wet quartz sands when manufacturing products of limited sizes from them. Products of limited sizes from frozen sand in foundry production are casting models used for manufacturing volumetrically closed and detachable casting molds using the SMS-process method, frozen casting molds and rods, etc. The work used quarry quartz sand of the 1K2O202 brand and tap water. The mass was measured on a VTA-60/6-73-AL-2 scale with an accuracy of ±1 g. The temperature was measured with an alcohol thermometer of the TTZ type and a chromel-copel thermocouple complete with an electronic device of the STC-1000 brand with an accuracy of ±1 С with video recording of temperature changes over time with an interval of 1 s. Drying of sand was carried out in a microwave oven with a magnetron power of 900 W and a microwave radiation frequency of 2.45 MHz. Freezing of wet sand was carried out in a refrigeration chamber with a capacity of 17 kg/day at a temperature of -20 °C. According to the results of the research, it was found that flat products with a thickness of 10 mm, regardless of the water content (up to 12.5% above), under conditions of unidirectional heat removal, cool to 0 °C faster than dry quartz sand. Freezing of wet sand under conditions of multidirectional heat removal from it leads to a significant migration of water in the sand in the direction of gravity, i.e. from the solidification front of wet sand to a surface with a higher temperature, which is in the direction of movement of unfrozen water. Increasing the initial temperature of wet sand contributes to an increase in the rate of its cooling to 0 °C and the time of solidification of water, but increases the total time of solidification of wet sand.
Influence of Ice Structure on Vitability of Frozen Sand-Water and Sand-Clay Mixtures
(Dnipro University of Technology, Dnipro, Ukraine, 2024) Solonenko, Liudmyla I.; Uzlov, Kostiantyn I.; Kimstach, Tetiana V.; Mianovska, Yana 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.
Kinetics of Quartz Sand and Its Mixtures Drying by Microwave Radiation
(Dnipro University of Technology, 2021) Solonenko, Liudmyla 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.
Physicochemical Structure Features of Refractory Compositions with Inorganic Binders
(Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine, 2022) Liutyi, R. V.; Solonenko, Liudmyla I.; Osipenko, I. O.; Fedorov, M. M.; Moroz, B. I.
ENG: The article presents the study results of new inorganic binders and the physicochemical processes of their formation. The main purpose of the created materials is to make molds and cores for foundry production. Creating environmentally-friendly binders with a set of functional properties for foundry production is relevant worldwide. Therefore, scientists from different countries are paying special attention to the study of silicate and phosphate binders. The study analyzes the kinetics of the orthophosphoric acid interaction with several inorganic materials – pulverent pyrophyllite, disthene-sillimanite, a by-product of electrocorundum production, and sodium chloride. The phase and chemical composition of all formed binders have been established. In aluminum-containing compositions, those are represented by aluminum orthophosphates in crystalline and amorphous forms. Sodium metaphosphate is formed in the composition with sodium chloride. Peculiarities of the structuring compositions physical process with liquid glass and granular quartz filler due to steam-microwave treatment are determined. It is shown that structuring occurs due to dehydration, which is completed within 4…12 min, which allows reducing the liquid glass content in the composition to 1.5% while ensuring a high level of strength. The properties of structured compositions with the developed binding components are researched, and it is shown that all of them are competitive. Recommendations for their possible application were created.
Sand-Sodium-Silicate Mixtures Structured in Steam-Microwave Environment Effective Values of Thermo-Physical Properties
(Dnipro University of Technology, Ukraine, 2021) Solonenko, Liudmyla I.; Repiakh, Serhii I.; Uzlov, Kostiantyn I.; Dziubina, A. V.; Abramov, Serhii O.
ENG: Purpose. Sand-sodium-silicate mixtures, structured by steam-microwave solidification, thermo-physical properties integral-effective values during Al-Mg alloy and graphite cast iron pouring determination. Sand-sodium-silicate mixture apparent density changing according to quartz sand, cladded with sodium silicate solute, fractional composition and its influence on BrA9Zh3L bronze microstructure establishment. Methodology. Quartz sand with 0.23 mm average particle size, sodium silicate solute, aluminum alloy with 8.5 % Mg, flake graphite cast iron SCh200 (DSTU 8833:2019), bronze BrA9Zh3L (GOST 493-79) were used. Mixtures structuring was carried out in 700 W magnetron power microwave furnace. Sand-sodium-silicate mixture thermo-physical properties integral-effective values were calculated by G. A. Anisovich method, using castings results and molds thermography. Structured mixtures apparent density was determined on samples 50x120 mm dimension. Metallographic studies were realized using Neophot-21 optical microscope. Findings. It was found that with sodium silicate solute, used for sand cladding, amount increasing from 0.5 to 3 % mold material apparent density decreases and thermal activity lowers. This leads to castings grains size increasing. Mixture sodium silicate solute content was recommended limiting 1.5 % for fine-grained microstructure castings obtaining and cladded sand using, which particles pass through mesh side less 0.315 mm sieve. Sands with sodium silicate solute content more than 1.5 %, which don’t pass through sieve 0.4 mm mesh side, were recommended as casting molds heat-insulating material using. Originality. For the first time, when aluminum-magnesium alloy and graphite cast iron pouring, quartz sand cladded with sodium silicate solute in amount from 0.5 to 3.0 % (weight, over 100 % quartz sand), steam-microwave radiation structured, thermo-physical properties integral-effective values were determined. Practical value. Data obtained using will improve castings solidification time and rate analytical calculations accuracy, forecast level and residual stresses sign in them, shrinkage defects locations. This will reduce casting technology developing time and costs and castings manufacturability.
Technogenic Hazards Coefficient of Sand-Resin Mixtures in Foundry Manufacturing
(Dnipro University of Technology, Dnipro, Ukraine, 2024) Solonenko, Liudmyla I.; Uzlov, Kostiantyn I.; Repiakh, Serhii I.; Prokopovich, I. V.; Bilyi, Oleksandr P.
ENG: Purpose. To carry out a comparative quantitative assessment of environmental and sanitary-hygienic hazards of utilizing synthetic resins for manufacturing molds and rods in foundry production. Methodology. Quarry quartz sand brand 1K2O202, furan resin brand Permaset 839 and catalyst Permacat 128, aluminum alloy AL2, gray cast iron SCh200, carbon steel 30L, bronze BrА9Zh3L were used in the work. Chromel-alumel thermocouples completed with electronic potentiometer were used for thermography. Molds were made from quartz sand, furan resin and catalyst mixture. Casting mold heating depth determination from casting to temperatures above 400 °C was carried out by its thermogram graphical processing, which was obtained after casting mold pouring with aluminum alloy, bronze, gray cast iron and carbon steel. Findings. Among those studied, the most dangerous are urea-phenol-formaldehyde, urea-formaldehyde and urea-furan resins, and the least dangerous are phenol-formaldehyde and phenol-formaldehyde-furan resins. Ecological and sanitary-hygienic hazard level when using resin mixtures increases with increasing resin amount in mixture, castings walls thickness, their surface area, as well as with increasing temperature of melt poured into the mold. Originality. For the first time, in relation to foundry molds and rods in foundry production manufacturing, technogenic hazard coefficient (THC) has been developed and its value has been calculated. This, in fact, is air volume (m3) containing maximum permissible concentration of carcinogenic or poisonous substances released as a result of mold organic binder material destruction when pouring aluminum alloy, bronze, cast iron or steel. Practical value. The use of the research results makes it possible to increase the level of predicting accuracy of technogenic (sanitary, hygienic and environmental) hazards, accuracy level of calculating ventilation systems capacities in foundries, taking into account the serial castings production, castings structural features, as well as binding materials nature for foundry molds and rods for such castings.
Water Resistance of Structured Sand-Sodium-Silicate Mixtures
(Dnipro University of Technology, 2021) Solonenko, Liudmyla I.; Repiakh, Serhii I.; Uzlov, Kostiantyn I.; Mamuzich, I.; Bilyi, Oleksandr P.; Kimstach, Tetiana V.
ENG: Purpose. To establish regularities of changes in sand-sodium-silicate mixtures (SSSM) relative water resistance, structured by steam-microwave solidification method (SMS), on their structuring parameters and sodium silicate solute (SSS) dissolution conditions. Methodology. Technical purity water, SSS with 2.8–3.0 silicate modulus, quartz sand with 0.23 mm average particle size were used in this work. Studies were carried out on quartz sand samples, which were preliminarily cladded with 0.5–2.5 % (by weight) SSS and structured by SMS method. The fracture time of structured mixtures was evaluated on cubic specimens with 20 mm rib length, which were immersed in water at different temperatures. Findings. Changes in SSSM water resistance in water regularities depending on their manufacturing, use and storage conditions were established. Recommendations for SSSM rods removal from castings in water were developed. Originality. For the first time, it has been established that relative water resistance of the SSSM structured by SMS method decreases along with increase in water temperature in which it is destroyed. Depending on SSS mass used for quartz sand cladding in range 0.5–2.5 %, water resistance dependence on treatment in steam-microwave environment with 2–7 minutes’ running time acquires an inversion character with inversion point ∼3.1 minutes into the processing. For the first time, it has been discovered that in boiling water the relative water resistance of SSSM, structured by SMS-process and having preheating, monotonically increases with preheating temperature rising from 100 to 600 °С, sharply increases when heated to 600–700 °С and practically becomes absolute after preliminarily preheating to higher temperatures. Practical value. Research results will be useful in concepts of processes accompanying destruction of structured sands with water-soluble binders expanding, as well as in technologies and equipment development designed for SSS rods and mold rests removing from castings.