Papers by Volodymyr V Kukhar
Problems of Tribology
The article presents the results of experimental and industrial tests of physical and chemical pa... more The article presents the results of experimental and industrial tests of physical and chemical parameters of the experimental emulsol "Quakerol". According to the physicochemical parameters the experimental emulsol "Quakerol" differs from the used emulsol "Universal-1TS" by higher lubricating properties. Operating modes of stand and coiler electric motors of tandem mill at rolling of melts from experimental emulsol "Quakerol" lubricated with emulsol "Quakerol" and serial emulsol "Universal-1ТС" lubricated with conservation oil "OK-2" at LPTs were analyzed. The results of analysis of loads at rolling of strips with 0.68×1000 mm cross-section from pre-rolled sheet with thickness of 3.0 mm showed that the values of average total loads on stand motors and coiler of four-stand mill 1680 were higher when using experimental emulsol "Quakerol". The comparative analysis of experimentally obtained data on influenc...
Bookmarks Related papers MentionsView impact
IOP Conference Series: Materials Science and Engineering, 2020
The “wing nut” is a widespread transport and ship fixture designed to locking of hatches, covers ... more The “wing nut” is a widespread transport and ship fixture designed to locking of hatches, covers and portholes. A more advanced closed die forging for the “wing nut” forgings of transport fittings was proposed with preforming by new method of bulk buckling of billet with upsetting ratio (height to diameter ratio) of 4.2...4.4. The billet and process calculation were performed based on results of researched and a new die forging was tested on a screw friction press. The results of experimental studies conducted on model lead billets at room temperature, and steel billets heated to 1180 °C, confirmed the increase in the accuracy rate of the billet material utilization ratio (one forging mass to one billet mass ratio) from 0.519 to 0.734 and metal savings up to 41% in comparison with the basic die forging without preforming of billet. It is shown that the introduction of a preforming by bulk buckling operation improves the forgings macrostructure (grainflow) even for cases the initial ...
Bookmarks Related papers MentionsView impact
Запропоновані відносні критерії (макропоказники) у вигляді безрозмірних величин для оцінки геомет... more Запропоновані відносні критерії (макропоказники) у вигляді безрозмірних величин для оцінки геометричної формозміни заготовок при попередньому профілюванні випуклими подовженими плитами під наступне об’ємне штампування або кування. Отримав подальший розвиток метод визначення роботи деформації при об’ємній формозміні. Встановлений функціональний зв'язок макропоказників формозміни у поздовжньому, поперечному та висотному напрямках із питомою роботою деформації на прикладі профілюючого гарячого осаджування випуклими подовженими плитами мідних заготовок. При цьому отримані регресійні залежності макропоказників формозміни, що запропоновані, від геометричних та технологічних чинників. Проаналізовано зміну величини питомої роботи деформації впродовж профілюючого осаджування плитами із різним радіусом заокруглення.Purpose. Purpose of researching is conclusion in carry out of mixed empirical and theoretical methodic for determination of quantity of the work of deformation during profiled ...
Bookmarks Related papers MentionsView impact
Problem. Casting cranes are operated for a long time in difficult conditions - high temperatures,... more Problem. Casting cranes are operated for a long time in difficult conditions - high temperatures, dynamic loads, significant pollution of the environment. In this case, the value of dynamic loads arising during operation may exceed those adopted during the design, and adverse operating conditions are not taken into account at all. Refinement of methods for calculating the strength of cranes, the development of new methodologies is an important scientific and technical problem, the solution of which will improve the safety of the operation of load-lifting cranes, in particular foundry ones.Goal. The purpose of this work is to simulate loading during acceleration of the casting crane and analysis of the actual stress-strain state of the elements of the travers, taking into account the temperature effect and additional inertial loads. The object of the study is the pattern of stress distribution in the elements of the traverse. Methodology. The article proposes a methodology for model...
Bookmarks Related papers MentionsView impact
Goal: Mathematic model checking of the technological process of hot-rolled coils rolling at Ferri... more Goal: Mathematic model checking of the technological process of hot-rolled coils rolling at Ferriera Valsider SpA Steckel Mill. Method of doing research: The checking of the developed model was carried out to allow its applying for the rolling process design. The influence of the mill springe was taken into account. It was determined the influence over the actual temperature measuring of the previous transfer bar processing by means of water descaling that results in significant inaccuracies when further comparing to the calculation results. Value: The average inaccuracy when modelling the rolling temperature conditions at mill 3170 is from 8,27% to 9,11%, at mill 1780 is from 0,003% to -0,92%. The average inaccuracy when modelling the rolling force at mill 3170 is from 0,5% to 5,7%, at mill 1780 is from -4,89 to 6,59%.В работе исследована математическая модель процесса прокатки горячекатаных рулонов на стане Стеккеля завода Ferriera Valsider SpA. Выполнена проверка разработанной мо...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Проанализировано влияние режимов ковки на эксплуатационные характеристики деталей путем улучшения... more Проанализировано влияние режимов ковки на эксплуатационные характеристики деталей путем улучшения макроструктуры и микроструктуры металла. Приведены результаты металлографических исследований поко-вок роликов МНЛЗ. Рассмотрена внедренная в условиях ПАО «ММК им. Ильича» технология ковки в комби-нированных бойках, которая позволила добиться улучшения показателей механических свойств металла на 10-20 %, уменьшить неравномерность структуры. Ключевые слова: стойкость деталей, макроструктура, микроструктура, ковка, механические свойства, не-равномерность структуры. An influence of condition of forging during operation for performances details by the way improvements metal's macro-and microstructure was analyzed. Are resulted metallographic researches of forging's rollers of CCM. It is considered introduced in the conditions of OSC "Ilyich Iron and Steel Works of Mariupol" technology of a forging in combined dies, which has allowed to achieve improvement of mechanical pro...
Bookmarks Related papers MentionsView impact
Lecture Notes in Mechanical Engineering, 2022
Bookmarks Related papers MentionsView impact
Problems of tribology, 2020
The article analyzes the known constructions of roller units of carts for the manufacture of aggl... more The article analyzes the known constructions of roller units of carts for the manufacture of agglomerate and pellets on conveyor lines. The article points out the advantages and disadvantages of roller designs, the lack of standard technical solutions for the design of roller assemblies, as well as reliable methods for calculating their parts for strength and durability. To increase the life of the rollers, the authors, after successful industrial tests, offer innovative technical solutions: seals in the form of stuffing boxes made of expanded graphite fibers reinforced with steel thread; bearing antifriction filler made from polytetrafluoroethylene, carbon fiber and graphite. The article shows that due to axial loads during the operation of the bogies, it is impractical to use ball bearings in the ball, they should be replaced with roller bearings. The authors propose an approximate method for calculating the durability of bearings, which additionally takes into account the elastic...
Bookmarks Related papers MentionsView impact
Engineering, 2020
Bookmarks Related papers MentionsView impact
2019 IEEE International Conference on Modern Electrical and Energy Systems (MEES), 2019
The conditions of operation of reversible cold rolling mills from the point of view of the charac... more The conditions of operation of reversible cold rolling mills from the point of view of the characteristics of the power load on electric motors are considered in the paper. The necessity of ensuring the reliability and stability of the modes of electrical, control and automation equipment is provided to achieve the high quality and absence of folder defects in thin cold rolled strips. The necessity of rolling with special emulsions has been substantiated. The research of operation of the electric motor of a reverse cold rolling mill and two coilers while rolling by plant modes using "Universal-TS" and "ColdRoller" emulsions was performed. Favorable softening of the rolling conditions from the point of view of the detected amperages in the electric motors of the rolling mill has been established.
Bookmarks Related papers MentionsView impact
Выполнен анализ основных способов дифференцированного нагрева в процессах обработки металлов давл... more Выполнен анализ основных способов дифференцированного нагрева в процессах обработки металлов давлением. Обосновано, что безручьевые способы предварительного профилирования заготовок перед горячей объемной штамповкой для прогнозируемого формоизменения рационально комбинировать с их градиентным нагревом, который изменяет пластические свойства заготовки дифференцированно по длине. Высказана гипотеза, что наиболее эффективное управление формоизменением при градиентном нагреве реализуется в случае, ко гда распределение температур по длине профилируемой заготовки соответствует распределению деформаций. Предложено 18 основных вариантов нагрева для получения различных конфигураций полуфабрикатов. Экспериментально подтверждено, что безручьевое профилирование заготовок продольным изгибом с неравномерным нагревом по длине позволяет увеличить локальные линейные размеры сечения на 38…45 %. Кроме того, становится возможным профилирование части заготовки и повышается эффективность гибки-профил иро...
Bookmarks Related papers MentionsView impact
IOP Conference Series: Materials Science and Engineering, 2020
Bookmarks Related papers MentionsView impact
IOP Conference Series: Materials Science and Engineering, 2020
List of the most used functions (circle, parabola, ellipse, hyperbola, cosine, hyperbolic cosine)... more List of the most used functions (circle, parabola, ellipse, hyperbola, cosine, hyperbolic cosine), which are applied to approximate of billets contours at upsetting and pointed to the lack of a universal equation for these purposes, was analyzed. The advantages and disadvantages of each type of equations are pointed. The paper presents the results of upsetting of lead cylindrical specimens with a upsetting ratio 2.0-4.0. The experiment shows the stages of a “double barrel” forming on the lateral surface of a billet and its subsequent transition to a single one. The authors propose to use the “superformula” recently invented by Johan Gielis as a universal equation that allows to approximate the contour of the lateral surface of a billet at all stages of upsetting. The paper presents comparative initial data necessaries to determine upsetting force and pressure, taking into account the barrel-shape calculated by the superformula, and the coefficient of friction determined by Gubkin’s ...
Bookmarks Related papers MentionsView impact
IOP Conference Series: Materials Science and Engineering, 2020
Steel hollow sections are common for transport engineering, vehicles, highway guardrails. The spe... more Steel hollow sections are common for transport engineering, vehicles, highway guardrails. The special requirements for strength and stiffness are determined by tests. The three-point bending test experimental and FEM research were carried out on steel rectangular hollow sections (RHS) with a cross section of 40 mm × 50 mm, manufactured in two ways: (a) by cold bending of steel strips on roll-forming mill in semi-closed section with a longitudinal gap of 0.5 mm between the edges formed on a 40 mm web (B-RHS); (b) similar cold roll-forming to the closed section and welding with a longitudinal weld along the web middle of 50 mm (BW-RHS). As a result, the graphs and analytical equations for relating the force (P) and deflection (f) at load on 50 mm and 40 mm webs were obtained, and revealed the advantages of bent-welded sections (BW-RHS) by stiffness and strength. FEM was performed using the SolidWorks CAD/CAE system for various RHS wall thicknesses (t = 1.93 mm, 1.84 mm and 0.7 mm). It...
Bookmarks Related papers MentionsView impact
Scientific journal of the Ternopil national technical university, 2020
Bookmarks Related papers MentionsView impact
Mechanics and Advanced Technologies, 2018
Bookmarks Related papers MentionsView impact
Bulletin of Kharkov National Automobile and Highway University, 2019
Bookmarks Related papers MentionsView impact
Collection of Research Papers of the National Mining University
Bookmarks Related papers MentionsView impact
Measurement Techniques
Bookmarks Related papers MentionsView impact
Uploads
Papers by Volodymyr V Kukhar