ННІ "Дніпровський металургійний інститут" (ДМетІ)

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https://crust.ust.edu.ua/handle/123456789/19780
ENG: Dnipro Metallurgical Institute

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Browsing ННІ "Дніпровський металургійний інститут" (ДМетІ) by Author "Abramov, Serhii O."

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    Sand-Sodium-Silicate Mixtures Structured in Steam-Microwave Environment Effective Values of Thermo-Physical Properties
    (Dnipro University of Technology, Ukraine, 2021) Solonenko, L. 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.
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    Texturing the Lamellae of the Collector of Electrical Machines
    (IEEE (Institute of Electrical and Electronics Engineers), 2019) Abramov, Serhii O.; Synytsina, Yuliia; Gryshin, Volodymyr; Serdiuk, Tetiana M.; Babiak, Mykola O.
    ENG: The main reasons for reducing the dynamic stability of the collector node during operation are caused by the lack of precision in the manufacture of individual elements. As a result of the analysis of technologies and methods for the treatment of surfaces with specified parameters, a jet-abrasive method was reasonably adopted, which allows texturing surfaces with high productivity.To optimize the processing modes using this method, a mathematical model has been developed for the interaction of abrasive particles with the surface of a copper lamella. The optimization criterion was the microrelief of the surface, the removal of the material appeared as a restriction. In addition, full-scale optimization was carried out for clearly not present technological parameters in a mathematical model, such as abrasive concentration and processing time.Experimental studies were carried out that confirmed the adequacy of the simulation and the correctness of the chosen technology. On this basis, an experimental batch of collector nodes was manufactured under production conditions. In this batch, the three nodes were made of textured copper lamellas, and three - control, according to factory technology.Manufacturing tests have shown that texturing surfaces with an increase in roughness without removing the material and without changing the geometric parameters of the profile allows in the zone of contact of copper lamellae with insulating plates to increase the coefficient of static friction, which leads to an increase in pressing force and, thus, obtain guaranteed tension and solidity collector site.