Статті КМТОМ (ДМетІ)
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Browsing Статті КМТОМ (ДМетІ) by Author "Bilyi, Oleksandr P."
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Item 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.Item Technogenic Hazards Coefficient of Sand-Resin Mixtures in Foundry Manufacturing(Dnipro University of Technology, Dnipro, Ukraine, 2024) Solonenko, Lyudmila 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.Item Water Resistance of Structured Sand-Sodium-Silicate Mixtures(Dnipro University of Technology, 2021) Solonenko, L. 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.