Application and schemes of induction preliminary heating in magnetic-pulse treatment of metals

The features of the processes of magnetic-pulse processing of metals in traditional schemes of technological processes of modern industrial production are highlighted. The work is a brief description of the state, application, and also proposed induction pre-heating schemes in industrial magnetic-pulse processing of metals. A method for increasing the efficiency of performing specified production operations is considered. The use of preheating leads to a significant improvement in the quality of production operations while reducing energy consumption. New directions of magnetic-pulse processing of metals are noted, implying the transformation of the natural repulsive forces of the metal of the processed object into the forces of magnetic-pulse attraction with a decrease in the operating frequencies of the acting fields. A significant decrease in operating frequencies makes it possible not only to go from repulsion to attraction, but also to go from working with ferromagnetic metals to non-ferromagnetic ones. For example, it becomes possible to attract aluminum blanks. Examples of the use of induction heating of metal blanks in modern industry are given. Various devices used for these operations, offered on the modern market, by both domestic and foreign manufacturers, are considered. The physics of Lenz-Joule heat release is described, the result of which is the induction heating of conductors by Foucault currents in the external electromagnetic field of the instrument. Schemes are proposed for the practical implementation of preliminary induction heating during magnetic-pulse processing of metal blanks, allowing the use of both autonomous devices for exciting eddy currents and a stationary connection, for the same purpose, of an additional source of electricity. As a result of the work, the possibility of increasing the efficiency by increasing the plasticity of the metal when heating the workpiece, as well as possible limitations of the described technology associated with an increase in the active resistance of metals with an increase in the Lenz-Joule heat release is noted.

SPECIFIC FEATURES OF DETERMINING THE DESIGN OF OXYGEN TUBE TIPS UNDER NON—STATIONARY CONDITIONS OF CONVERTER MELT WITH PRELIMINARY HEATING OF SCRAP

The results of calculating the parameters of the tips of oxygen lances, taking into account the preheating of scrap metal in the converter due to the combustion of solid fuels in the modern raw material conditions of a metallurgical enterprise of Ukraine, are presented. The substantiation of the design of blowing devices is provided. The results of calculating the geometric parameters and the coefficient of off-design for standard and experimental tips of oxygen lances are presented. Using numerical methods, the value of the diameters and length of the supercritical part of the nozzle was obtained. It is shown that with a decrease in the blast flow rate, it is advisable to decrease the length of the supercritical part of the nozzle, which is fully correlated with the literature data. The change in the coefficient of off-design was determined for the studied range of oxygen consumption (600—1100 m3 / min) for standard and experimental handpieces. It is shown that the value of the coefficient of off-design is in the range of 0.52—0.98 and 1.30—2.30, respectively, for 5– and 6–nozzle standard tips. For experimental tips, this figure is 1.00—1.70. Tuyeres with experimental tips, at the pressure available in the shop, reliably operate in the range of oxygen consumption 650—950 m3 / min and allow increasing the oxygen consumption at the beginning of the blowdown to 1000—1100 m3 / min and more, if necessary. The resulting saving effect from the introduction of the modernized tips is: a decrease in the oxidation of the final slag 1.22—1.70 %; reduction in the specific consumption of lime 0.29—1.81 kg / t; reduction of specific consumption of metal charge 0.26—0.38 kg/t.

The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl2-Based Plasma for Integrated Optics Applications

Chlorine processes are widely used for the formation of waveguide structures in InP-based optoelectronics. Traditionally, ICP etching of InP in a Cl2-based plasma requires substrate temperatures in the range of 150–200 °C. This condition is mandatory, since during the etching process low-volatility InClx components are formed and at insufficient temperatures are deposited onto substrate, leading to the formation of defects and further impossibility of the formation of waveguide structures. The need to preheat the substrate limits the application of chlorine processes. This paper presents a method of ICP etching an InP/InGaAsP heterostructure in a Cl2/Ar/N2 gas mixture. A feature of the developed method is the cyclic etching of the heterostructure without preliminary heating. The etching process starts at room temperature. In the optimal etching mode, the angle of inclination of the sidewalls of the waveguides reached 88.8° at an etching depth of more than 4.5 μm. At the same time, the surface roughness did not exceed 30 nm. The selectivity of the etching process with respect to the SiNx mask was equal to 9. Using the developed etching method, test integrated waveguide elements were fabricated. The fabricated active integrated waveguide (p-InP epitaxial layers were not removed) with a width of 2 μm demonstrated an optical loss around 11 ± 1.5 dB/cm at 1550 nm. The insertion loss of the developed Y- and MMI-splitters did not exceed 0.8 dB.

Computer 3D-simulation of the temperature and diffusion kinetics of SHS in the closest packing of Ni@Al “core-shell” mesocells for modes with variable values of the key ignition parameters

The paper presents the results of computer 3D-simulation of the temperature and diffusion kinetics of SHS in a test model cluster of Ni-Al particles for modes with variable values of the key parameters of the SHS combustion wave ignition. The key parameters for the SHS combustion wave ignition were chosen as follows: the initial temperature for preliminary heating of the Ni-Al particles mixture, the ignition temperature of the combustion wave in the mixture of Ni-Al particles, the duration of the action of the heat pulse until the combustion wave ignition, and the thickness of the ignited layer in the mixture of particles. A program has been created to generate a test model cluster in the form of the closest ball packing of the Ni@Al “core-shell” mesocells (CBP-structure cluster of the Ni@Al “core-shell” mesocells). Using such a CBP-structure cluster, was continued a testing of created software package intended for 3D-simulation of SHS macrokinetics in a heterogeneous particle mixture, taking into account parallel MPI-calculations. In addition, the value ranges of the key parameters of the SHS combustion wave ignition for which the simulation results are in adequate agreement with the experimental data are determined as the parameters of the program model for SHS-simulation. The results of computational experiments have shown that diffusion kinetics is interrelated with temperature kinetics, and in mesocells with different locations within the CBP-structure cluster, the formation of intermetallic phases occurs inhomogeneously.

INFLUENCE OF SURFACE PRE-HEATING ON THE NITRIDING DEPTH OF STEEL 25CrMoVA USED COMPLEX ION-PLASMA TREATMENT

In the method of nitriding elements, various methods of their thermal heating are used. The simplest heating method in ion-plasma nitriding is heating by bombarding the surface first with low-energy gas ions and then with metal ions with energies up to several kiloelectronvolt. Elements exposed to ion bombardment have a welldeveloped surface that is free from contaminants and facilitates the diffusion of nitrogen into the depth of the metal during nitriding. The paper studies the effect of various preliminary heating methods on the nitriding depth in the complex ion-plasma hardening technology of 25CrMoVA steel. A JSM 7000-1F scanning electron microscope equipped with an X-ray spectral energy dispersive microanalysis attachment was used to diagnose changes occurring on the surface of the samples and at depth; the hardness was measured using a Nanoindentor G200 device. The preliminary heating of the samples was carried out both with the use of bombardment with Ti or Mo ions, and without its direct effect on the heated surface. In the experiment, differences in the depth of hardening of the nitrided layer of steel are observed when it is heated in different ways. When bombarded with Mo ions, the greatest depths of hardening were obtained in comparison with other preliminary heating conditions. It is shown that these differences are associated with the features of the morphology of the steel surface formed as a result of sputtering processes. The formation of nitride compounds in its surface layer can serve as a barrier that slows down the penetration of nitrogen into the metal. It is shown that with complex treatment in the process of deposition of a nitride coating on the surface of nitrided steel, an additional increase in the depth of hardening of the nitrided layer occurs.

STUDY INFLUENCE THE DESIGN ОXYGEN LANCE HEAD ON THE RESULTS OF CONVERTER MELTING WITH SCRAP PREHEATING

The results of calculation of energy efficiency of the variant of technology of converter smelting with preliminary heating of scrap metal in the unit due to burning of solid fuels in modern raw material conditions of the metallurgical enterprise of Ukraine are presented. A critical analysis of the variant of converter smelting technology with the use of preheating of an increased amount of scrap metal in the charge containing briquettes of steel chips in the unit, before pouring processing iron. According to the results of the calculation of the efficiency of use of different types of fuel used for preheating of scrap metal in the unit, the rational type and technology of its use in converter smelting are determined. A direct connection between the chemical composition of briquettes, the level of their preheating and the share in the metal charge on the energy efficiency of the converter process and their chemical heat content has been established. The nature of the temperature distribution in the volume of briquettes from steel shavings, which are a part of the metal charge, is taken into account when they are preheated by oxidation of coal with oxygen supplied through the nozzles of the standard lance. A method for calculating the change in energy consumption of scrap metal during its preheating, taking into account the content of elements in the briquettes and the level of heating. The energy consumption of the converter process with preheating of the metal charge increases in proportion to the level of contamination of briquettes from steel chips with non-metallic inclusions. According to the calculations when heating briquettes by 100—800 degrees in the converter, the increase in energy consumption of the converter process is from 60 to 630 MJ / t and from 445 to 1000 MJ/t for contamination of briquettes with non-metallic inclusions of 2.47 and 7.87 % by weight in accordance. With the reduction of briquette contamination, the efficiency of preheating of the metal charge increases. The share of the impact of the level of briquette contamination on the overall energy efficiency of the converter process is on average 0.3 % of the total energy savings of 1.91—1.92 GJ / t, which is achieved by increasing the share of scrap metal in the charge.

The Influence of Mixing Methods of Epoxy Composition Ingredients on Selected Mechanical Properties of Modified Epoxy Construction Materials

The proper process of preparing an adhesive composition has a significant impact on the degree of dispersion of the composition ingredients in the matrix, as well as on the degree of aeration of the resulting composition, which in turn directly affects the strength and functional properties of the obtained adhesive compositions. The paper presents the results of tensile strength tests and SEM microphotographs of the adhesive composition of Epidian 57 epoxy resin with Z-1 curing agent, which was modified using three fillers NanoBent ZR2 montmorillonite, CaCO3 calcium carbonate and CWZ-22 active carbon. For comparison purposes, samples made of unmodified composition were also tested. The compositions were prepared with the use of six mixing methods, with variable parameters such as type of mixer arm, deaeration and epoxy resin temperature. Then, three mixing speeds were applied: 460, 1170 and 2500 rpm. The analyses of the obtained results showed that the most effective tensile results were obtained in the case of mixing with the use of a dispersing disc mixer with preliminary heating of the epoxy resin to 50 °C and deaeration of the composition during mixing. The highest tensile strength of adhesive compositions was obtained at the highest mixing speed; however, the best repeatability of the results was observed at 1170 rpm mixing speed. Based on a comparison test of average values, it was observed that, in case of modified compositions, the values of average tensile strength obtained at mixing speeds at 1170 and 2500 rpm do not differ significantly with the assumed level of significance α = 0.05.

EXPERIMENTAL RESEARCH OF THE NON-VIBRATING METHOD OF LAYING CONCRETE MIXTURE IN CANAL CLADDING

The results of experimental studies are presented which make it possible to correct the technological parameters of laying the concrete mixture in the cladding of newly erected or reconstructed water supply canals. The studies were carried out on an experimental stand simulating the cannel profi le with a variable slope angle from 15° to 90°. The stand slope is covered with a conditional soil model in the form of a rough surface. To determine the relationship between the speed of the vibromold movement, the parameters of the concrete mixture, the profi le of the canal and the parameters of the concrete paver, mathematical models of the technological process have been developed. The analysis of the obtained results shows that accelerating additives signifi cantly reduce the duration of the concrete reaching its critical strength, in other words, it reduces the duration of the curing of the concrete under the formwork. The study of the obtained surface of the cladding on the stand shows that it contains some irregularities due to the absence of a smoothing strip. Therefore, under production conditions, concrete pavers must be equipped with smoothing devices, and the concrete mixture must be placed through a special hopper that regulates the height of the concrete mixture supply. For the construction of concrete linings on mobile concrete mixtures, it is recommended to use accelerating additives or their preliminary heating to a temperature of 50 … 60°C.

ВЗАИМОСВЯЗИ ТЕХНОЛОГИЧЕСКИХ ПРОЦЕССОВ ГЛУБОКОЙ ПЕРЕРАБОТКИ ПТИЧЬЕГО ПОМЕТА

Запевалов М.В., Качурин В.В., Наруков Е.Н. КЛЮЧЕВЫЕ СЛОВА: ПТИЧИЙ ПОМЕТ, ПЕРЕРАБОТКА, ТЕХНОЛОГИЧЕСКИЕ ПРОЦЕССЫ, СВЯЗИ, ВЫСОКОТЕМПЕРАТУРНАЯ СУШКА, ПИРОЛИЗ, ОРГАНОМИНЕРАЛЬНОЕ УДОБРЕНИЕ АННОТАЦИЯ: Разработана схема комплексного технологического процесса глубокой переработки птичьего помета, состоящая из отдельных технологических процессов: предварительного подогрева помета, высокотемпературной сушки, брикетирования, газификации методом пиролиза и приготовления органо-минерального удобрения. На основе данной схемы разработана блок-схема внешних связей процесса глубокой переработки помета, которые представлены как система с детализацией по основным технологическим процессам. При разработке очередного этапа переработки помета учитывается его состояние на предыдущем этапе, то есть производится решение многоэтапной задачи, причем на каждом этапе предусматривается выполнение определенного количества технологических операций для достижения желаемого результата. При этом отдельные операции не рассматриваются вследствие их достаточной изученности и неизменности. Определены основные факторы и разработана операторная схема технологии глубокой переработки помета. INTERRELATIONS OF THE TECHNOLOGICAL PROCESSES WITHIN THE TECHNOLOGY OF DEEP PROCESSING OF POULTRY MANURE ZAPEVALOV M.V.1, KACHURIN V.V.1, NARUKOV E.M.2 1 South Ural State Agrarian University, Chelyabinsk 2 Chelyabinskaya Poultry Farm The technology of deep processing of poultry manure has been developed involving the processes of preliminary heating of the manure, high-temperature drying, briquetting, gasification by pyrolysis, production of an organomineral fertilizer. On the basis of this operational sequence the block-scheme of external interrelations between the detailed processes within the technology was developed. Each following process is designed on the basis of the condition of the manure after previous process; the entire technology is therefore designing as a multi-stage system with definite number of technological operations within each stage to obtain the desirable result. Individual stages are considered well developed and unalterable. The main influencing factors were determined and operational scheme of the technology was developed. Keywords: POULTRY MANURE, PROCESSING, TECHNOLOGICAL PROCESSES, INTERRELATIONS, HIGH-TEMPERATURE DRYING, PYROLYSIS, ORGANO-MINERAL FERTILIZER