Reporter of the Priazovskyi State Technical University. Section: Technical sciences

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Authors: S.V. Shchetinin, V.I. Shchetinina, P.V. Nikitenko, О.V. Koval

The electromagnetic nature of the undercuts formation has been established. As welding speed increases, the diameter of active spots decreases, heat input to the side edges of the bath reduces, the electrical resistance of the side edges decreasing. As a result, the amount of current flo wing through the bath side edges increases as well as increase of the field induction, electromagnetic force and the magnetic pressure, under which the liquid metal flows down from the bath edges, which leads to the undercuts formation. The regularity of the electrode shape influence and the metal thickness on the formation of welded joints and the undercuts formation is established, according to which, with a decrease of the metal thickness, the tendency to undercutting decreases as a result of a decrease in the ferromagnetic mass directed downward in the region of the bath side edges of the electromagnetic forces and magnetic pressure, what provides the qualitative welds formation and confirms the electromagnetic nature of the undercuts formation. A method has been developed for high-speed one-side welding with a composite electrode. This process provides a heat input increase to the side edges of the bath, electrical resistance increase, current decrease, electromagnetic forces and magnetic pressure, directed downward in the regions of the bath side edges decrease, high-quality seams without undercuts, the reverse roller on the flux cushion, the microstructure grinding and an increase in the toughness of welded joints

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Authors: G.U. Burlakova, T.G. Danilova

The current conflict of interests between the carrier and the passenger, sharpened by the outdated state of the existing system of passenger car transportation, requires from the organizers a clear structure of interaction between carriers and passengers based on the effective system of organization of urban passenger transport operation, which is ensured by the introduction of a single logistic (dispatching) center in the organization of passenger transportation by the city transport. The conducted monitoring of the organization of urban passenger transportation in the present systems leads to the conclusion that the current organizational status of passenger transportation has a significant effect not only on the security and organization of passenger transportation, but also on its quality, the inadequacy of which is felt by passengers as users of transport services. Improving the quality of transportation will provide a real opportunity to raise the level of competitiveness of road transport enterprises engaged in the process of passenger transportation, which in its turn will eliminate the conflict situation between carriers and passengers in terms of transportation quality. The article considers and analyzes the values of the optimal system for organizing urban pas-senger transportation, examines the possibility of using two variants of the existing systems of organization of transportation by passenger urban transport, analyzes the need for the introduction of a single dispatching (logistic) center into the operation of urban transport

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Authors: V.I. Burlakov

During the economic recovery of the country, special attention should be paid to the technical re-equipment of all the branches of national economy. In particular, it is recommended to pay special attention to the development and introduction of equipment for fundamentally new technological processes. The main task in the field of mechanical engineering is increasing the productivity, economy, reliability and durability of the parts produced, labor input and labor costs reducing, integrated automation and mechanization of labor-consuming manual processes. At present, the level of technical perfection of metalworking and stamping production has reached a new qualitative level. There exist highly productive automatic lathes and stamps with automatic feeding of metal tape as well as semi-automatic machines with numerical control. Therefore, the labor consumption in manufacturing small parts has sharply decreased. However, further progress in the metalworking and stamping industry is significantly hampered by the lack of highly productive cleaning methods, especially for complex shape parts and small masses up to 40 g. So, for example, after cutting off the rings on the lathe turret, the labor of removing the burrs located on the edge of the cutoff is 300-350%, and removing the burrs after stamping is 400-450% of the labor consumption in manufacturing these parts. The complexity of cleaning these parts results from their intricate shape and small size that prevent them from being properly processed in vibration-abrasive machines or tumbling drums, while ultrasonic methods can’t be used either because of their relatively large mass. From the analysis of various scientific sources, it can be seen that turbulent-abrasive treatment is mainly used for rigid parts of simple design, vibration-abrasive processing with large oscillation amplitudes is more expedient for parts of complex configuration with grooves and holes, including the parts of low rigidity. The creation of vibro-abrasive machines with large oscillation amplitudes (10-20 mm), even with small volumes of the working chamber (up to 1 liter) is associated with a great structural difficulty, as well as with the solution of questions regarding vibration and noise insulation. Thus, the cleaning of the parts of small stiffness with a mass of 25-40 grams up to this time remains nonmechanized and manual

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Authors: O.M. Zynovchenko, G.G. Garkusha

Powerful single-phase electrical energy consumers distort the voltages of three-phase networks. The use of adjustable symmetric devices assumes measuring the asymmetry of voltages. Since the asymmetry of voltages in three-phase networks is limited by the level of 2%, an accurate measurement of its parameters, and especially the argument of negative sequence voltage, is complex. A brief analysis of the known methods for measuring the parameters of asymmetry of a three-phase voltage system is given. The multi-phase rectification method has the highest accu-racy. In this method the investigated three-phase system of voltages is converted into a multi-phase voltage system that feeds the multi-phase rectifier and the output voltage of this rectifier is analyzed. The constant component of the output voltage of the rectifier gives information as to the direct sequence voltage. The second harmonic of the output voltage of the rectifier gives information as to the negative sequence voltage. It is shown that the negative sequence voltage argument can be measured as a phase shift between the second harmonic voltage of the rectified line voltage and the second harmonic voltage of the output signal of the multi-phase rectifier fed from the voltage system that is being studied. But the accuracy of such measurement is low. It is shown that the introduction of a correcting signal significantly improves the accuracy of the measurements. The correcting signal is formed from the measurement results of the asymmetry voltages factor and the phase shift between the second harmonics. Introduction of the correction will reduce the absolute maximum methodical measurement error, by a factor of 20 for 10% asymmetry of voltages

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Authors: L.Yu. Nazuta, O.V. Fedorova, Y.V. Khavalits

Object of investigation: Low-alloyed structural steels microalloying with boron technology. Method of investigation: analysis of boron assimilation degree from the statistical analysis of the smelting of the current production. Purpose: determination of the optimal mode of out-of-furnace treatment in order to obtain the maximum degree of boron assimilation. Technical and economic advantages of structural steel microalloying with boron have been analyzed. It has been shown that the beneficial effect of boron on technical characteristics (primarily on hardenability) is due to the peculiarities of the structure of boron atoms and shows itself only in steels subjected to thermomechanical processing. The ability to intensively change the structure of a metal is a prerequisite for reducing the content of nickel, molybdenum and other alloying elements in them. The dynamics and structure of boron-containing steels production have been analyzed, the main steel grades microal-loying with boron has been considered. The influence of the degree of metal de-oxidation and the titanium consumption on the boron specific consumption and assimilation degree has been studied using the A514B steel as an example. It has been shown that modern out-of-furnace tools (ladle furnace-UKP unit and VD vacuumers) make it possible to increase boron assimilation and, consequently, metal quality

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Authors: S.S. Samotugin, V.О. Haharin, V.А. Mazur

A technique for calculating the design parameters of an indirect action plasmotron for surface modification of complex shape parts has been proposed. The plasma modification process parameters characteristics, their mutual influence, the possibility of regulation have been given. The qualitative parameters of the plasmotron are influenced, first of all, by the parameters due to which the plasmotron is formed – arc current, the kind of the plasma-forming gas and its flow rate, the speed of the plasmotron movement and the parts. The diameter of the plasmotron channel and the nozzle apertures provide compression and stabilization of the plasma arc. The length of the channel and the distance to the surface being treated provide the maximum thermal efficiency and plasma temperature. The outer dimensions of the plasmotron are obtained from its design, proceeding from the necessity to be sufficiently cooled. It is necessary to take into account not only the requirements imposed on the hardened workpiece surface, but also on the mutual influence of these parameters. When changing the hardening parameters, it is important to save the service life of the plasmotron. This is possible with the correct choice of the cooling mode. A calculation of the liquid flow rate through the cavity of the plasmotron that is necessary to fulfil the given conditions and secure the proper heat exchange has been made. Tests of plasmatrons of various designs. confirmed the data of the calculations

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Authors: E.О. Chaplygin, M.V. Barbashova, О.S. Sabokar, I.S. Ryabukha

The article presents the results of electromagnetic processes research in the induction heating system. The system of the induction heating consists of flat circular multiturn solenoid. It is located above the plane of thin-walled sheet non-magnetic metal. Calculation dependences have been got for the current induced in the sheet metal blank and the ratio of transformation. The ratio of transformation is determined as a relation of amplitudes of the exciting current and the current induced in the blank in the circle of radius. Maximum ratio of transformation is defined taking into account spreading of eddy currents over all the area of sheet-metal. Calculation dependances for the estimation of the thermal processes at heating ferromagnetics by a flat multiturn solenoid have been obtained. The definition of the «relative heating temperature» integrally takes into account the influence of the skin effect peculiarities on the temperature indices of induction heating, that is, not only the conductive but magnetic properties of the metal of the blank. This makes it possible to perform all the necessary numerical estimations of the characteristics of the processes in the «inductor‒sheet blank» system under consideration, taking into account the peculiarities stemming from field penetration processes during induction heating of thin-walled ferromagnetics

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Authors: O.A. Khliestova, T.A. Levitskaya

The article discusses methods and techniques of interactive training in solving environmental problems, in studying the role of the anthropogenic factor in changing the quality of the environment, in the scale and consequences of climate change, and in the choice of ways for improving the living conditions. The work suggests the use of innovative training technology in the form of a web-quest, by creating an information space for solving problems related to environmental issues; a possible target audience is described, a phased plan for organizing and conducting a web-quest is developed. Detailed description of the technical part of the «Web Quest» project, including the choice of the tools and programming language, an analysis of possible options for the implementation of the web-quest, a modern range of information technology preferable for the creation of the quest- Node.js, React, MongoDB- have been selected and proposed. The development of the quest structure as a stable, scaled architecture with a valid set of control points, the corresponding class of application databases, taking into account the features of the functional have been described. It is shown that the technology of web-quests, using the Internet information resources and integrating them into the educational process, helps to solve a number of practical and social problems effectively, and the web-quest as an educational event for students and the general public makes it possible to increase general awareness of the population, to choose measures to protect the environment and to form the most favorable and comfortable living conditions, to adapt to climate change

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Authors: V.S. Voloshin, N.Yu. Yelistratova, V.A. Burko

Modern methods of assessing working conditions and safety of work at an industrial enterprise are considered in the implementation of European standards in the field of labor protection. The main approaches have been marked out in identifying hazards at work, assessing technological risk and injuries at a metallurgical enterprise. The purpose of this work is to analyze the effectiveness of the introduction of international methods in the field of labor protection and industrial safety, to assess the effectiveness of the safety management system at an industrial enterprise. The analysis of the process of implementing European standards in the field of labor protection at industrial enterprises in Ukraine is a prerequisite for their further successful application, reducing the level of occupational injuries. The procedures for drawing up the matrix of risk assessment – HAZID, assessment of working capacity of technological processes – HAZOP, safety assessment of works – JSA are considered. The analysis of the effectiveness of measures to increase labor safety in the energy sector of the enterprise was carried out. A graph of the dynamics of the decline in occupational injuries in five years is shown. The main statistical indicators that are used to account for industrial injuries at an industrial enterprise are given

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Authors: L.Yu. Nazuta, O.V. Fedorova, Y.V. Khavalits

Object of research: boron-containing steels. Method of study: analysis of deoxidation thermodynamics in the Fe-B-O system. Purpose: The choice of the most reliable constant values of iron deoxidation with boron as well as on the basis of this, the development of the most effective technologies of microalloying with boron. In the work on the basis of theoretical and experimental data got by various au-thors, the iron deoxidation with boron over the range 0,001% to 0,01% is analyzed. It is shown that boron oxide В2О3 forms independently of the boron content in the Fe-B-O melt. It is shown that the data of thermodynamic calculations and experimental researches by different authors (irrespective of the method of their calculations) differ just slightly. At 1600°C, the value of the deoxidation constants according to the data got by various authors is relatively stable and is: K-1В-O = (0,36-0,46)•10-8. For practical calculations the work of I.S. Kulikova should be recommended. The effect of boron on the oxygen activity is relatively low. With boron content of less than 0,1% in case of В2О3, formation the interaction parameter will be = -(0,39-0,40). The effect of boron on its own activity is estimated by the coefficient = 0,065 + 0,01[В]. The microalloying with boron as well as its peculiarities have been studied. Boron influence on the operational properties of steel due to structural changes during crystallization and heat treat-ment have been studied The practice of microalloying with boron, technology of out-of-furnace treatment, including joint doping with strong deoxidizers aluminum and calcium, has been considered

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Authors: M.A. Ryabikina, V.Ye. Stavrovskaya, M.О. Ksenita

The effects of vanadium and niobium microalloying on the microstructure and mechanical properties of structural steel have been studied. In low carbon steel containing vanadium and niobium, the contribution to hardening of the following mechanisms increases: grain refinement, hardening by dispersed precipitates of carbides and nitrides, dislocation hardening. These chemical elements refine the grains, enhance microstructure uniformity and mechanical properties of low alloyed steel. In the present work, statistical analysis of the acceptance testing results of the normalized rolled S355J2 steel has been performed. The sampling amounts to 15619 meltings. The meltings were divided into 2 parts: the first included the melting alloyed with vanadium, the second included the melting alloyed with niobium. The minimum yield strength was 373 MPa for melts with vanadium and 400 MPa for melts with niobium, which is higher than the required by 20-40 MPa. The values of the tensile strength fit into the required interval 470-630 MPa. The average values are ~545 MPa. The minimum values of the KV-20 impact energy are 3-4 times higher than the required 27 J. The average values of KV-20 (with vanadium) = 159 J and KV-20 (with niobium) = 168 J. Thus, steel S355J2 is charac-terized by a stable and high complex of mechanical characteristics. Tensile test and Charpy test at negative temperatures show good combinations of strength and ductility due to microalloying additions.In this paper the composition-property relationships are also shown: σ0,2 = 392%V + 408 (MPa), R = 0,4; KV-20 = = 583%V + 134 (J), R=0,35; σ0,2 = 692%Nb + 402 (MPa), R = 0,46; KV-20 = 1204%V + + 130 (J), R = 0,52. Microalloying with just vanadium in amounts of 0,01-0,10% or only with niobium 0,01-0,05% increases the yield strength of S355J2 steel by ~30 Mpa, the impact energy is increased by ~40 J. From the obtained «composition-property» models it follows that niobium has a more significant influence on the mechanical characteristics of S355J2 steel

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Authors: S.V. Mazur, V.M. Strilets, O.R. Strilets, A.A. Stepaniuk

The article deals with the design and operating principle of a mechanical seal of increased tightness. Mechanical seals consist of non-rotating and rotating friction rings. The non-rotating ring is installed in the housing, and the rotating ring is installed in the sleeve, which is connected with the shaft by means of a key. A groove in the form of Archimedean spiral is made on the face surface of the rotating ring. The non-rotating and the rotating friction rings are pressed together by means of a pressure element spring. Movement of fluid that tries to get through the friction rings junction from outside and falls into the groove in the form of Archimedean spiral and its return to the air-tight cavity has been investigated. To obtain analytical expressions of fluid movement that has penetrated into the groove in the form of Archimedean spiral from the face surface of the rotating ring with a rectangular cross section, the scheme of forces acting on the elementary volume of fluid has been shown; corresponding differential equations being written and solved. Using the analytical expressions and computer simulation, graphic dependences have been obtained on the strength of which the operating conditions of the considered mechanical seal have been got

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Authors: T.N. Karpenko, P.S. Тanasienkо, S.R. Fedorova

The known energy method based on the law of mechanical energy conservation of the mechanical system with one degree of freedom is generalized in the article, that makes it possible to decide the questions of natural frequencies and dynamic coefficient at different types of deformations. Considering Hooke's law on dynamic loading true and deformations and tensions increase gradual, (having potential energies on a static loading), we consider impact potential energy equal to initial kinetic energy of the mechanical system. Dynamic coefficient at torsion, flexural and longitudinal impacts has been got, and the literary source is indicated for the flexural impact in different points of a beam, taking into account the masses of the struck bodies. The obtained maximal stresses obtained at torsion and longitudinal impacts testify that in contrast to static stresses dynamic stresses at impact depend on the volume (but not on the area) of the struck body. Attention is drawn to the circumstance, that the dynamic coefficient at vibrations depends on natural frequency. Therefore the designers of machines must select inertness and other properties of the studied objects so that natural frequencies did not coincide with the shaft rotation frequencies and with the disturbance factors frequencies. Algorithm of calculations of dynamic–response factor at impact taking into account the struck body mass as well as algorithm of getting natural frequencies of longitudinal and torsion, flexural vibrations for some widespread calculation charts have been offered. The material of the article is taken from the known sources and generalized in a condensed form, (suitable for students and beginning designers) with the purpose of implementation of strength calculations of dynamic models with one degree of freedom

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Authors: V.E. Parunakajn, G.V. Maslak

Analysis of material traffic showed that it comprises several interacting elements including transport (railway) and production. On this basis the production-and-transport system (PTS) has been modeled. Its major element (subsystem) provides unloading of mass raw materials and finished products shipment, as well as internal (technological) transportations of semifinished products. From mass raw materials reception to finished products shipment, all the operations with railway cars which belong to different carriers are carried out by minor (servicing) subsystem (STS). Taking a large metallurgical enterprise as an example, an assessment of the functioning of the major and servicing subsystems has been made, quantitative indicators of the work of cargo, sorting, district and technological stations have been given; serious shortcomings being noted in the interaction of production and transport. It was determined that now both major and minor subsystems within PTS of enterprises do not comply with the production process requirements, due to management ineffectiveness and poor conditions for interaction between production and transport. This causes considerable transport expenses and significant production losses. In order to solve this problem, optimization models are needed. These should be based on logistical management of material traffic which, as a result, will secure transport expenses and production losses reduction

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Authors: T.V. Kostenko, V.K. Kostenko, S.М. Aleksandrov

Most often rescuers working at extinguishing fires are subjected to high air temperatures and intense thermal radiation. Particularly difficult is the microclimate The heat conditions when there gets more heat into the body than out of the body are particularly difficult by removal of excess radiation, moisture evaporation, heat exchange with the environment. Special heat protective means must be used under such extreme conditions. The reasons for thermal lesions and their complications are the lack of protective effect of the heat protective means, the rescue units are equipped with, and incomplete knowledge of the thermal factors and therefore erroneous actions of the executives responsible for firefighting. Therefore, improving the ways and means to protect rescuers from the negative impact of heat is important and urgent. Such passive methods as reflection of rays of heat isolating layers are mostly used in the firefighters’ protective equipment. Their disadvantages are a limited security resource that is just tens of seconds and a great probability of violating the integrity of the shells because of heating, aggressive chemicals and light radiation. The article proposed to improve the cooling system for the human body by adopting a flowing cooling scheme with heat absorbers located in the underwear space. This will ensure a practically unlimited resource of a coolant and increase the term of the heat protective means action. To increase the heat removal from the surface of the body by sweat evaporation it has been proposed to provide moisture sorption in underwear by installing absorbing elements. Water irrigation or foam barrier formation can solve the problem of thermal destruction of the outer shell cloth. Using the proposed constructive solutions will make it possible to increase the security resource of heat protective means and reduce the risk of their ruining during emergency works

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Authors: V.S. Kornienko

The heating surfaces pollution layer thickness versus the wall temperature during the 1000-hour flow influence at combustion of fuel-oil and water-fuel emulsions have been obtained. The heat conductivity research for various pollution conditions on the heating surfaces with regard to the accepted pollution structure were carried out. The obtained dependences show that the value of equivalent heat conductivity factor of pollution depends on the porosity, form and size of the particles in the layer composition and properties of the medium that fills the voids between the particles at the appropriate wall temperature. The results of experimental and rated pollution factors, heat transfer and thermal efficiency at combustion water-fuel emulsion for dry and condensing heating surfaces of exhaust gas boilers at wall temperatures over the range 70 to 210°C are presented. Analysis of the research re-sults shows that the combustion of water-fuel emulsions with water content of 30% reduces the layer of heating surfaces pollution and increases the value of heat transfer factor and thermal efficiency. The reliability of the obtained results with published statistical data for the burning standard fuels was verified. The obtained values of factors can be used both in the design and operation of condensing heat-ing surfaces

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Authors: М.D. Dyachenko

The given article is a review in its nature. The problems of monitoring the cable distribution networks and distribution transformer substations conditions have been discussed in the article. The necessity of their operation modes continuous monitoring is shown. The main attention in the article is devoted to the reviews of the SmartGrid data transmission channel for the «digital layer» making up. The main advantages and disadvantages of data transmission channels of both wire and wireless type have been considered. It is shown that the PLC technology application, as well as wire and even fiber-optic lines, is currently inexpedient from an economic point of view. The Smart Dust technology has been surveyed. It pro-vides secure self-tuning sensors-to- monitoring devices of different types communication. The main advantage of this network is that it can route the transmitted data by itself minimizing the number of active links in the network regardless of any circumstances. The expediency of communication channels with distribution transformer substations organization due to the GSM networks provided by mobile operators has been substantiated. However, it is necessary to duplicate the data transmission channel by using various transmission GSM technology methods (TCP\IP, UDP, CSD, DTMF, SMS, etc.). The need to duplicate the communication channel by using the services of two or more mobile operators is emphasized. From the analysis of the GPRS TCP \ IP service, it transpires to take into account the periodic disruption of the channel without signalling about the dis-ruption either to the server or to the client; the disruption caused, as a rule, by the reset of the APN servers of the GSM operator. It is shown that in the monitoring equipment of the substation it is necessary to provide independent watchdog timers for monitoring the system and network hangs, as well as an analyzer of temporary lack of data monitoring

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Authors: E.A. Chychkarov, V.A. Alekseeva

The analysis of the main approaches to the description of the processes of nonmetallic inclusions removal in the tundish during continuous casting is performed. It is shown that in studying the hydrodynamic processes in the tundish, the distribution curves of residence time (RTD) are widely used, which are described by a combination of idealized cells. A combined mathematical model for the removal of nonmetallic inclusions in the tundish of slab CCM due to flotation and floating is formulated. The possibilities of their removal for limiting variants of mixing condi-tions, ideal mixing and ideal plug cells, as well as the possibility of removal of nonmetallic inclusions with intermediate variants of stirring intensity, in the presence of circulation flows, are analyzed. It is shown that the comparatively higher proportion of large non-metallic inclusions remains at the outlet of the ideal mixing cell than in the outlet of the ideal plug cell, the increase in the fraction of the ladle volume with the ideal plug regime (with laminar flow) leads to a decrease in the residual fraction of nonmetallic inclusions. It has been determined by calculation that when blowing with argon in the casting section of the tundish of a two-strand continuous casting machine, the flotation efficiency depends on the size of the nonmetallic inclusions (small inclusions are practically not removed) and the size of the gas bubbles (small gas bubbles and a decrease in their dispersion in size provide a higher rate of removal of nonmetallic inclusions), as well as the average residence time of the metal in the bubbling zone. It has been calculated that the flotation of nonmetallic inclusions significantly increases the rate of removal of small particles with a diameter of 20-40 μm, which are practically not removed in the tundish without blowing, only with flow control devices. The results of the calculation are confirmed by the results of industrial experiments

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Authors: V.E. Krivonosov, S.M. Zlepko, S.V. Pavlov

Malfunctions that arise in the operation of diagnostics apparatus, can be divided into external, associated with poor-quality power supply system, and internal, resulting from the breakdown of blocks and elements of the devices themselves. The X-ray computer tomograph (RCT) is particularly sensitive to low-quality power supply. All the parts of the RCT possess high inductance L. Voltage drops result in internal overvoltages on the blocks of the RCT. To protect RCT, the use of high-speed characteristics of the voltage front change as the information parameter when detecting the emergency modes of the power supply network can treble the speed of the network mode detecting. Changes in the value of the speed characteristics at various values of the non-sinusoidal voltage, voltage deviations and frequency oscillations in the power supply network have been investigated. The range of the speed characteristic change for detecting voltage drops and voltage deviations have been developed.as well as the range for the normal operation of RCT and the range of the transition to an emergency mode

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Authors: S.V. Shchetinin, V.I. Shchetinina

The rolling-mill back-up rolls operate under high specific pressures conditions and are produced of high-carbon steel, prone to hot and cold cracking. Therefore crack resistance increase is an important scientific and technical problem. The impact of the electrode shape and heat input on the arc motion, and heat affected zone, the size of which determines the cold cracks formation and deposited metal flaking has been found. The arc moves along the electrode end face along the longitudinal axis or perpendicular to the weld pool in dependence on the ribbon position. The arc movement governs the heat input in the pool and if the surfacing regime is constant, the heating and cooling rates of the molten metal and heat affected zone as well. At surfacing with a perpendicular ribbon the heat affected zone decreases; at surfacing with a longitudinal ribbon and wire the heat affected zone increases. At surfacing with a composite electrode the heat affected zone reduces sharply while resistance to cracking and wearing increases. With the heat input reduction in weld pool side edges the heat affected zone reduces as well. At high speed surfacing with low heat input, the heat affected zone reduces, the tendency to cold cracking and deposited metal flaking decrease, welding stresses and specific pressure decrease, what results in resistance to cracking increase as well as the increase in wearing resistance. When energy decreases the deposited metal quality increases. Energy minimum results in maximum quality. The process of energy-saving high-speed deposition with low heat input, which provides microstructure reduction, heat input in the base metal and heat affected zone decrease, prevent cold cracking and deposited metal flaking increases both rolling mill back-up cracking resistance and wearing resistance has been developed

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Authors: O.M. Zhbanova, L.N. Saithareyev

The method of a crystallizing alloy processing which makes it possible to obtain high-quality castings from 35GL steel has been considered. It has been shown that the electro impulse treatment of the melt improves the structure and reduces the physical heterogeneity of the castings. Processing of the melt with a current substantially increases the dissolution rate of metallic impurities and other components in the melt, provides a fine-grained structure, increases the homogeneity of the cast metal as well. The structural heterogeneity decreases as a result of the change in morphology and disorientation and as a result of manganese carbides grinding the size and quantity of the grain ball decrease from 7 to 8. Physical heterogeneity reduces due to the changes in the location and size of pores and nonmetallic inclusions; the content of gases and non-metallic inclusions reduces as well. In this article, studies of the modification of certain parameters by the electric impulse current, have been made. It results in a significant increase in the basic mechanical properties of the 35GL cast structural steel: the tensile strength increases by 9%, the toughness increases by 21%, and the hardness by 6% without changing the chemical composition of the steel, due to the fine grain structure

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Authors: M.D. Dyachenko, S.V. Kodulev

The article considers the basic prerequisites for the creation of an automated monitoring system for oil pumps of high-voltage transformers. This is due to the fact that the long operation of oil pumps results in deterioration and destruction of bearings, rubbing of the rotor, breakage and damage to the impeller, leakage, etc., which inevitably causes a significant decrease in the insulating properties of the transformer oil and leads to expenditures for its further recovery. False triggerings of gas protection sometimes occur. Continuous operation of the electric motor also requires additional equipment to protect the motor itself from various emergency situations, such as a short in the stator winding, a housing breakdown, an incom-plete phase mode, etc. The use of stationary systems provides: diagnosing defects at an early stage of their development, increasing the reliability and longevity of the equipment components, increasing the overhaul period, decreasing the number of emergency stops, and adjusting the schedule of preventative maintenance. The basic principles of identification of the damaged part of the oil pump are given, the hardware and algorithmic solutions are considered in the work. The full-scale tests of the model sample on the power transformer of the high-voltage substation confirmed the assumption of the possibility of detecting the damaged unit separating it from the rest connected in one mechanical structure. A detailed analysis of the operation of each of the units is carried out by means of the general substation switchboard and displayed as graphs, diagrams and text messages. When the limit values of vibration are reached, faults in the operation of the unit are detected, the overlimit current values, a warning alarm is activated, and the command to disconnect the damaged unit is issued. The optimal solution for the organization of the information collection system using the principle of sensor networks, but combined via Wi-Fi technology, is given

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Authors: I.F. Tkachenko, M.A. Uniyаt

An actual scientific and technical task solution, that is operational performance improvement, elimination of the mechanical and physico-chemical properties anisotropy by optimizing the chemical composition has been given in the paper. Using the methods of the deep data analysis, the effect of production parameters (chemical composition and thickness of rolled metal) on the key indicators of the mechanical properties – ultimate strength, yield strength, percent elongation and impact resistance-has been investigated. It is shown that the most responsive characteristic of mechanical properties – impact resistance, is influenced by the elements: C, Mn, Si, P, H2. According to the results of the research it is shown that under operating conditions by optimizing the chemical composition of the in-vestigated steels by means of the CHAID method and with the use of quality criteria the optimal concentration ranges of chemical elements, which ensure high and stable levels of plasticity and the work of the blow of rolled low alloy steels may be determined. The influence of thermal treatment on the chemical distribution of elements, microstructure, hardness and mechanical properties of the welding manganese steels has been researched. Using the methods of mathematical analysis, the chemical composition of the steel E36 has been investigated.

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Authors: O.A. Zhuchenko, M.G. Khibeba

A comparative analysis of technical and economic indicators as criteria for optimal electric calciner control has been done. It is shown that the use of the considered factors has some drawbacks resulting from the operating conditions. The modified factor of specific operating costs as the factor, that makes it possible to fully evaluate heat treatment of carbon materials in electric calciner efficiency has been proposed. The use of the electric calciner in the production of carbon products has been substantiated. Mathematically formulated control task setting includes selected optimality criterion and limitations. Optimality criterion based on the specific operating costs and takes into account costs that depend on technological mode and actual electric calciner performance. The specific operating costs includes material costs of raw materials, energy costs for carbon materials movement in electric calciner and for material heating by Joule heat. Actual electric calciner performance defined as the part of all processed material that has good quality. Limitations consist of material electrical resistivity at the outlet of the apparatus limitation, the temperature of heat treatment limitation, electric power applied to the electrodes limitation and material heat treatment time in electric calciner limitation. Using these limitations when creating control system allows to keep product quality specified value and take into account device design features, carbon material and material heat treatment process in electric calciner features. Control task solving should provide optimally carbon materials heat treatment process functioning in terms of resource and energy saving mode and as a result, improve production of carbon products efficiency in general

7

Authors: Levitskaya Т.O. , Ganzina D.I.

This article focuses on the justification of the use of cryptosystems based on a mathematical model of the chaos generator (an electric circuit, showing modes of chaotic oscillations), proposed by Leon Chua in 1983. This article also describes the principles of implementation of cryptographic algorithm and its application prospects. Reviewed the next questions: the problems of widespread cryptosystems, the theory of cryptographically strong algorithms, absolutely and computationally secure ciphers, particular theoretical method for solving the problem of increasing the reliability of hybrid computational proof systems by inclusion of a mathematical model of chaos as a generator to encrypt transmitted data key. Here described the recommendations on the implementation of cryptographic system and requirements on the Chua’s circuit generator chaos

7

Authors: A.I. Kovaliov, S.A. Vedula, O.V. Grushovinchuk

The subject of predicted durability term of steel constructions coatings using accelerated tests and experimental determination of steel constructions coatings fire-resistance after weather testings is raised in the article. The benefits and drawbacks of steel constructions in present-day building industry and construction design are introduced. The factors influencing steel constructions fire resistance increase are presented. The article shows that the most advanced and ideal for the protection of steel constructions is using the agents that expand and blow up under the temperature influence, forming thus a porous structure on the surface to be protected. The stages to receive the necessary indexes of predicted durability term of steel constructions coatings as well as methods to carry out climate tests both in the heated and unheated premises are described. For experimental determination of steel constructions coatings fire resistance it is suggested to use the method based on the experimental determination of the temperature of a steel plate with fire-resistant coating in the conditions of high temperatures typical of a fire, and on the solution of inverse and direct tasks of heat conduction for determination of thermal and physical characteristics of fire-resistant coatings and dependence of minimum coating thickness on the thickness of the steel plate, durability of fire impact and the steel critical temperature value. It is concluded that there is the necessity to develop the methodological support that makes it possible to estimate the coatings fire-resistance after or in the process of carrying out the accelerated climate tests as compared to the control examples. The list of problems that come into being while determining the steel constructions coatings fire-resistance after the climate tests is distinguished as well as the purpose of the future researches and tasks that should be solved

8

Authors: O.V. Berezshnaya

The machine parts recovered by electric contact surfacing with metal strip are characterized by high loading of the surface layer, which has a significant impact on their performance. Therefore, the improvement of the operational stability of fast-wearing machine parts through the use of combined treatment technologies is required. Not all the work-piece but just the worn zones are subjected to recovery with electric contact surfacing; the tape thickness and depth of the heat affected zone being not more than a few millimeters. Therefore, the most optimal in this case is the use of a local surface heating method of high frequency currents. This method has economical benefits because there is no need to heat the entire work-piece. The induction heating mode at a constant power density has been proposed and analytically investigated. The ratios that make it possible to determine the main heating parameters ensuring calculation of the inductor for the normalization of the reconstructed surface of cylindrical parts have been given. These parameters are: specific power, frequency and warm-up time. The proposed induction heating mode is intermediate between the quenching and cross-cutting heating and makes it possible to simultaneously obtain the required temperatures at the surface and at the predetermined depth of the heated layer of cylindrical parts with the normali-zation of their surfaces restored with electric contact surfacing

8

Authors: S.S. Samotugin, V.А. Haharin, V.A. Mazur, O.Yu. Nesterov

The microstructure of carbon and alloy steels with various carbon contents before and after the gradient hardening by means of highly concentrated plasma jet have been investigated. It is shown that the resulting structure after the surface hardening has a substantially smaller grain size as compared to the bulk hardening. The steels with different carbon content, that is hypoeutectic steels 45 and 50HN, eutectic steels – M76, U8, hypereutectoid steels – 90HF, U10 have been researched. Processing was carried out under the optimal conditions to ensure the highest hardness of the surface without melting. Metalgraphical studies were carried out using optical and scanning electron microscopes. High-dispersed martensite is the main structural component for hypoeutectic steels. Despite the fact that the heating temperature and the cooling rate in different parts of the plasma exposure zone differ greatly, the structure of the tempered zone is uniform by both the degree of dispersion and by the values of hardness. Plasma treatment of eutectic steels results in fine-grained structure of martensite of mainly lamellar morphology. High-dispersed martensite with microparticles of secondary carbides is characteristic of the hardened zones for hypereutectic steels. But austenite grains do not grow at heating as it usually happens in bulk hardening. The structure of the transition zone corresponds to part-hardened steels. So excess ferrite as well as martensite retains in hypoeutectic steels while excess cementite retains in hypereutectic steels. Eutectic steels are free from the intercritical interval, and the transition zone does not practically develop, there being a very sharp boundary between the zone of full hardening and the parent metal. Due to this structure of the plasma hardening zone of the surface layer there arises 3,5...4,5-fold increase in the hardness of the steel as compared with the normalized condition. This is due to the increase in the degree of saturation of the solid solution with alloying elements and carbon, and size-reduction of the hardened structure

8

Authors: I.V. Zhezhelenko, V.V. Nesterovych

A comparative analysis of the known methods of calculating additional power losses caused by a decrease in its quality has been performed. It has been shown that the known methods of estimating additional power losses assume the use of a large amount of initial information as to the parameters of electrical equipment and the electric network regime, which makes their application unnecessarily complex and time-consuming in a significant number of cases. Based on the analysis, a classification has been developed and possible areas of applying these methods have been defined, and the requirements for them have been formulated. Using the example of determining the additional power losses caused by distortion of the shapes of the current and voltage curves, it has been shown that the known techniques assume the use of data on the values of higher harmonics of currents in individual branches of the electric network as the initial information. It is suggested, in the future, to consider the possibility of using as the initial data of this calculation the values of the higher harmonics of the voltages at the network nodes, which will simplify the calculation. At the same time, the resulting underestimation of losses can be eliminated by introducing correction factors that take into account the increase in the currents of higher harmonics in individual branches

8

Authors: O.M. Khalimovskyy, O.L. Sokolskiy, V.M. Kurylenko

A device design has been developed that makes it possible to insert intelligent sensors (IS) into the products from composite polymeric materials to control their stress-strain state. The results of the experiments made it possible to improve the algorithm of coordinated work of the vector controlled induction electric drive of the device elements. The simulation results of the transient processes of the operating conditions of the IS automatic insertions into the predetermined spatial coordinates of the extruder channel polymer have been shown. The presence of such sensors within the given spatial coordinates of a product is realized due to rapid movement of molten polymer with included IS under use of the scheme of influx fitting to the polymer that moves in the main channel of the extruder. Based on the simulation results a dependence function for the immersion depth of the polymer melt with included IS from its movement velocity has been obtained. The approximation of this dependence via a polynomial function of 5-th order made it possible to determine with the relative error less than 1% analytically the linear velocity of the rod in the cylinder injector for transporting of the molten polymer with included IS to the predetermined spatial coordinates of the polymer channel of the extruder. For inserting of the intelligent sensors (IS) into the depth of 1.2 mm a required motor speed of electric drive was calculated under considering of the peculiarities of the chosen kinematic scheme. The obtained experimental data have confirmed the possibility of technical implementation of the developed device as well as allowed refining of the algorithm for the automation system. The simulation results for the system have been presented. The system used the vector-controlled asynchronous electric drives with standard settings for their contours to provide the agreed movement of the plasticiser screw and the injector rod by inserting of IS at a given depth with a given step

8

Authors: J.V. Bulgakova, T.A. Hutsal

The multi-modal freight transportation routes planning problem is viewed in this paper. The case study of iron ore deliveries to the metallurgical enterprises of Mariupol from Kryvyi Rih is presented. Based on the analysis of Ukrainian railroads and sea ports infrastructures six possible routes of multi-modal iron ore transportation are built. The paper presents a short review of route planning problem in multi-modal freight transportations, which are use sea and land parts together, regarding decision support methods of routes evaluation and selection. The lack of studies dedicated to fuzzy logic theory application for solving the stated problems is identified. The relevance of fuzzy set application to the route planning problem is proved. Taking into account the peculiarities of iron ore transportations technology, the following criterions of routes evaluation are chosen: «transportation costs», «delivery times», «transportation risks». The model of multicriterion decision-making of routes evaluation and the optimal route selection, based on fuzzy logic theory, is developed. Criteria of routes evaluation are set by three terms Gaussian and sigmoidal membership functions. The approach to each function construction is practice-based and executed together with iron ore supply chain manager. The model is created in MATLAB Fuzzy Logic Tool Box environment using Mamdani’s fuzzy inference

9

Authors: О.P. Cheiliakh, M.A. Ryabikina, N.E. Mak-Mak

The essential relationship of high-altitude indexes of roughness Ra, Rz Rmax of worn out surface and the relative wear resistance of the surface layers of the steels (0,27% C) and (0,55% C, 1% Mn) after carburizing and quenching by different regimes have been established. An opportunity to apply the methods of statistical analysis for evaluation of the shape roughness was shown. A correlation between the coefficient of relative durability and characteristics of the worn-out surface shape was found. The opposite effect of the heating temperature for quenching on wear resistance and surface roughness was displayed. The wear resistance of carburized steel (0,27% C) and (0,55% C, 1% Mn) is increased by quenching from 1000°C due to changes in the structural-phase state of the surface layer. Wearing out of the hardened surface is more smooth and even due to the high content of Ares in the carburized structure, that is capable of ′ strain-induced martensite trans-formation at wearing (DMTW). DMTW causes additional self-strengthening of the surface working layer as deformation martensite is more dispersed and solid as compared with quenching martensite. The interrelation between wear resistance and surface roughness has been defined. With an increase in the wear resistance of the investigated steels the roughness characteristics decrease following the linear pattern

9

Authors: V.V. Burlaka, S.V. Gulakov, S.K. Podnebennaya, O.S. Savenko

The paper proposes a method for controlling the electric power quality parameters in a distribution network by modifying the control algorithms for electric loads equipped with active rectifiers fed from this network. Thus, by controlling the reactive component of the input current of such rectifiers, it is possible to reduce the voltage fluctuations at the point of common connection (PCC), the efficiency of such a method being higher the higher the X/R ratio of the network is. It is also possible to reduce the voltage harmonics in the PCC by integrating the functions of parallel active filters into active rectifiers. The proposed method allows for limited control over the flow of inactive power in the distribution network, which makes it possible to improve the electric power quality and reduce the required power of the filter compensating devices. The proposed algorithm for controlling the active rectifier is tested on the mathematical model of group loads. A group of high power resistance welding machines (RWMs) operating randomly with a normal probability distribution connected to 0,4 kV grid as a non-stationary load is used. The application of the proposed reactive current control method in the RWM power supplies made it possible to reduce the voltage fluctuations in 0,4 kV grid from 12% to 5%

10

Authors: V.Y. Lobov, K.V. Lobova

The purpose of this article is to solve the problem of fuzzy control of iron ore pellets thermal treatment on a conveyor roasting machine, to build an automated control system of conveyor roasting machine and perform simulation and to present the results of research. According to the structural scheme of the fuzzy control an automated control system is proposed for being modelled. This is done by using the software MATLAB. The use of atomic emission spectroscopy determines the percentage of the major elements in iron ore pellets considering the main process parameters. This article uses an automated system of fuzzy control of iron ore pellets firing on a conveyor roasting machine with the introduction of atomic emission spectroscopy of the pellets. Development and practical implementation of fuzzy control will improve their quality by taking into account the basic parameters of thermal treatment of pellets such as speed of movement of the grate trucks, gas flow rate, the height of the layer of pellets and the venting speed of the pellets layer with gas-air flow, humidity, average diameter, the basicity and the iron composition in the pellets. The expediency of the developed method of using automated fuzzy control system of iron ore pellets firing on a conveyor roasting car has been proved. The system with fuzzy controller provides a reduction on average 2 m3/h, which is 0,3% of natural gas consumption as compared to the existing systems. This provides more uniform gas permeability of the layer of pellets, which leads to filtration rate increase of the gas flow and to heat exchange intensification in the layer of pellets. It makes it possible to introduce the atomic emission spectroscopy of non-burned pellets and to increase the productivity of conveyor roasting machine by 2,5%. At the same time the resistance of technological equipment (pallets) increases, due to more uniform distribution of the thermal field

11

Authors: О.S. Anishchenkо, V.V. Kukhar, E.A. Mktrchan

. The paper shows that the contour of a sheet blank at all stages of superplastic forming can be described using universal formulas known as a «superformula» Gielis and «superellipse» Lamé. The work provides information on the values range of the coefficients entering into these formulas. The paper shows the results of approximation by means of the proposed formulas of shell contours manufactured by superplastic forming by different methods. The application of the «superformula» to approximate the spherical shell contours in the first stage of molding has been tested. The graphs that show the ratio of the ordinates of the contours of the spherical shells and the hemisphere are given. It is shown that the contours of the shells from the AlMg5 and Pb-38%Sn alloys are rejected in the direction of the formation of parabolas. It was found that the deviations increase with decreasing the coefficient of high-speed hardening of the alloy of the shell. The contour of AMg6 alloy shells and blanks of variable thickness, with maximum in the central zone, is diverted from the hemisphere towards the ellipse. The first stage of forming in a non-uniform temperature field forms a contour of shells, similar to an ellipse. Forming shells with the ratio of the height (H) and the radius (R) as H = 0,6R in the angular zones of the matrix forms intermediate contours of different shapes. This shape depends on the presence of lubricant between the shell and the bottom of the matrix