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Information × Registration Number 0217U002271, 0115U000171 , R & D reports Title Control of heat-exchange processes at energy-efficient gradient heating of billets and development of energy-saving electrothermal heaters. popup.stage_title Head Kukhar Volodymyr Valentynovych, Registration Date 01-02-2017 Organization State Higher Educational Institution "Pryazovskyi State Technical University" popup.description2 The object of study - non-stationary processes of heat transfer with the formation of low-power thermal profile during energy-saving gradient heating of billets and their contact with the tool before the subsequent technological working. The aim of research is to increase the technical and economic indices of the heating process in the electrothermal heaters (reduction of energy consumption, increase the heating rate, the expansion of product ranges), the formation of scientific and methodological basis for the study of non-stationary heat transfer to the achievement of sustainable thermal profile of the workpiece at energy-saving gradient heating, as well as the development of practical recommendations for the design of induction heaters. Research methods and instruments. The methods: system analysis and thermodynamics of non-stationary processes; theory of heat conduction and heat and mass transfer; physical experiment, experiment planning, approximation and processing of experimental data; recurrent solution of the heat transfer equation in the finite-difference and finite element formulation for the development of numerical mathematical models. Methods, ideas and hypotheses of the research's authors: the approximate method of accounting in the calculation of the thermal field changes of thermal properties of materials, depending on technological factors and thermo heating and deformation of workpiece; the hypothesis about the distribution of cross-sectional changes in die-free profiling of workpiece occurs equidistant to curve of temperature profile of the workpiece at its gradient heating; techniques and software developed by the authors. Theoretical and practical results. A scientific and methodological basis for the study of non-stationary heat transfer with the formation of a rational thermal profile of the workpiece at a differentiated energy-saving heating, as well as practical recommendations for the design of electrothermal heaters are carried out. The established form of the thermal profile allows controlling the mechanical properties of the workpiece, its configuration during forming operation as forging, stamping, rolling with the implementation of energy-saving methods of law-tool or tool-free working. Practical results are achieving to substantial of much energy-saving and next technical and economic effects: a) reduction of 20...30% of energy costs due to the participation of the smaller volume of metal in the heat exchange processes; b) increasing the heating rate of workpiece to 15...25%, and in cases of high-speed heating in inductors with variable coil pitches - up to 3 times; c) an increase in the range of complex configuration profiles with the expansion of the range of products that are produced on a one equipment unit, with a decrease in energy consumption and a reduction of die-tool costs; d) a method for calculating the minimum allowable technological temperature of gradient heating of the workpiece is carry out. Novelty. 1. For the first time established a rational form of gradient curves of temperature distribution for die-free profiling of workpiece, that is the source of information for the design of inductors for gradient heating with the creation of sustainable thermal profile of the workpiece and allows to save energy costs and material resources. 2. For the first time obtained patterns of change of curves of the temperature gradient distribution along the length of the workpiece after gradient heating and at contacting of the workpiece with deforming tool that allows to create the conditions for the control of heat transfer and forming processes at deformation of workpieces without the use of complex profiling tool, die impressions and gauges. 3. Get the further development the methods for the solution of non-stationary heat transfer problems for determining the final temperature distribution at the initial non-uniform temperature distribution in the body of finite length. Solutions include a comprehensive account of changes in the initial conditions and the boundary conditions in the process of heat transfer, body sizes, and changing the thermophysical properties of materials of contacted bodies at temperature changes. The effectiveness of implementation. The efficiency is the achievement of specific energy saving per weight of unit of heated material. Energy consumption in conventional induction heating of the order of 1440 MJ/ton (400 kW*h/ton), and using a gradient of heating is reduced to 900 MJ/ton (250 kW*h/ton), while productivity of induction units increases from 1.0...1.5 to 4.0...5.0 ton/h. Scope (industry) of use. Using the developments aimed to the sector of mechanical engineering, metallurgy, instrumentation, cable industry, the balloon industry with preheating of workpieces prior to subsequent forming operations by forging, stamping and rolling. The developments are introduced in educational process of metal-forming department of SHEI "PSTU". Recommendations for improvement of hot die-forging processes for "Movable plate" and "Support" forgings in the conditions of PJSC "AzovEktroStal" and PJSC "GSKTI" are carry out. The recommendations can achieve the expected energy savings, metal savings up to 15%, improve the filling of die impressions and increase their tool-life by 12%, reduce the consumption of dies materials at 18 ... 23%. Product Description popup.authors Аніщенко Олександр Сергійович Балалаєва Олена Юріївна Василевський Олег Вікторович Кокташ Христофор Павлович Кухар Володимир Валентинович Мкртчян Єгор Арутюнович Ніколенко Роман Сергійович Присяжний Андрій Григорович Саврухіна Наталія Олександрівна Сердюк Олексій Іванович Снісаренко Костянтин Анатолійович popup.nrat_date 2020-04-02 Close