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

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Authors: V.P. Kravchenko, U.A. Lazarevskaya

The opportunities to get clinker (cement) on the basis of 2-component mixtures of raw materials: waste slag + limestone (less than 10mm fraction) unsuitable for sinter production and being a technological waste of preparing raw materials for steel production have been investigated. Chemical compositions of waste slag and limestone wastes were investigated in the central laboratory at the Illych plant. The waste slag was got at the «Ilyich» plant while waste limestone - less than 10 mm fraction - was got in the dumps of the mine group in Komsomolsk. Taking into account chemical composition fluctuations of the waste dump slags and limestone within a few percent, the optimal ratio of raw materials is 55-65% limestone waste, while it is 35-45% waste slag. The clinker quality is evaluated by its hydraulic module, which is equal to: m = 2,37 and is determined on the basis of the chemical composition of the 2-component raw material mixture. For this method of clinker production, the value of the hydraulic module is rather high; and the possibility of obtaining high-quality clinker of metallurgical wastes has been confirmed. The offered method for producing clinker makes it possible to utilize metallurgical wastes and to get substantial ecological and economic benefits

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Authors: V.A. Royanov, I.V. Zakharova

It has been shown that the electric arc spraying with the use of powder wires can be used to repair and restore parts of metallurgical equipment. The technology of spraying parts by means of the cored wire Steelcored M8TUV; T462MMIN5 and combinations of steel and aluminum wires to restore shaft-gears, shaft-beams, cranes axles for the foundry of the Moldavian Metallurgical Plant has been intro-duced. The composition of the flux-cored wires MMP-2,3 developed at the Department of Equipment and welding production technology of PSTU that provides the required hardness and adhesion of the coating and the substrate have been shown and the results of the coatings properties studies have been published. Studies have shown matching properties of the coatings to be used for details of the metallurgical equipment working under difficult conditions, including the rolls of rolling mills. Cored wire was used for pilot plating of the rolls surface of the skin-rolling stand at the cold-rolling mill at Illich Steel and Iron Works, Mariupol. Residual coating thickness ranged from 15 to 25 microns. Strip sized 0,9 × 1025 mm has been rolled, the squeezing is equal to 0,8...1,0%.

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Authors: V.S. Voloshin, V.A. Burko

Phosphorus has more affinity for oxygen than for iron. Therefore it retires in the process of scorification at the advent of steel becoming compounds and gets into slag increasing its acidity. Mathematical model of phosphorus bearing components movement in metallurgical production has been made by the use of flow chart theory. Phosphorus bearing wastes utilization alternatives in the production of agricultural fertilizers have been offered. Nowadays in modern industry phosphorus is rather poorly used and, being dumped, is the reason for environmental pollution. Phosphorus bearing components in metallurgical slags can be most readily used in agriculture. The given morphological scheme of phosphorus in metallurgical conversions as well as converter slag and phosphorus fertilizer comparison in composition make it possible to realize all the main functions of metallurgical technologies focused on phosphorus contents change. Comparison between converter slag and phosphoric fertilizer has been made in chemical composition. Phosphorus processing technology has been developed within the framework of converter production

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Authors: N.V. Suslo

Such properties of cast iron as hardness and shock resistance are relevant and have been investigated. Some possible ways to improve these properties have been studied and solutions to the assigned tasks in accordance with modern trends have been found. The use of nano-dispersed modifiers is most promising in modification. The compositions of experimental complex briquetted modifiers have been developed. The technology of cast iron processing with complex briquetted modifiers has been developed. A series of experiments on the effect of a complex briquetted modifier introduced into cast iron on its properties were carried out. The rational content of components in the briquette that makes maximum use of the modifying effect and improves such service characteristics of cast iron as hardness, impact - and wear-resistance has been defined. Ways of a briquette destruction in metal have been explored. The effect of an organic binder amount on the de-struction of a briquette and its dissolution in the melt has been investigated. Rational composition of the briquetted modifier that makes it possible to increase hardness and impact resistance of cast iron has been developed

6

Authors: V.О. Mazur

Crane operation results in wear and tear of rails and crane wheels. Renovation and efficiency of these details is therefore relevant. Modern technologies of wheels and rails restoration use surfacing or high-frequency currents treatment. Surface treatment with highly concentrated streams of energy- with a laser beam, plasma jet- is a promising direction.. It is proposed to increase the efficiency of crane rails by means of surface plasma treatment. The modes of treatment have been chosen.. Modelling of plasma jet thermal impact on a solid body of complex shape has been made. Plasma hardening regimes that meet the requirements of production have been defined. Structural transformation of the material in the crane rails on plasma treatment has been investigated. It has been concluded that for carbon and low alloy crane steels the plasma exposure zone is characterized by a high degree of hardened structure dispersion and higher hardness as compared to the hardness after high-frequency quenching. As this takes place phase transformations are both shift (in the upper zone of plasma influence) and fluctuation (in the lower zone of the plasma). With high-speed plasma heating granular or lamellar pearlite mainly transforms into austenite. The level of service characteristics of hardened steel, which is achieved in this case is determined by the kinetics and completeness of pearlite → austenite transformation. For carbon and low alloy rail steels plasma hardening can replace bulk hardening, hardening by high-frequency currents, or surfacing. The modes for plasma treatment which make it possible to obtain a surface layer with a certain service characteristics have been defined

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Authors: О.D. Uchitel, G.M. Panchenko, D.V. Popolov

The grate bars of the conveyor roasting and sintering machines work in severe, aggressive dust and gaseous medium, under cyclic modes «heating-cooling», as well as under the load of iron ore agglomerates what results in bending stress in the body of the grate bar. Consequently, electric steel grate bar must be resistant to chemical and erosion processes, high cyclically changing temperature and have high mechanical properties. The paper discusses the conditions of the grate bars of conveyor roasting and sintering machines wear, depending on the adopted loading schemes. The materials to be processed can be loaded directly from the hopper (direct download) or through the use of a feeder (drum-type feeder, roller, etc.). A simplified method to predict the grate bars surface wear on the strength of a number of assumptions has been developed: normal reaction of the pallet surface to the impact of the batch is assumed constant, equal to the maximum of its value when the pallet is in horizontal position; a layer of the batch moves as a rigid body; surface batch layer sliding velocity as related to the pallet surface is taken medium during the relative motion of the layer and equal to the linear velocity of the pallets; the side faces of the grate bars wear is related to related to the surface wear by linear dependence. The dependence of the wear on the friction forces and the steel wear resistance coefficient has been found out

7

Authors: Y.M. Kovrygo, R.P. Sakov

Steam generating unit automation control system is a complex system with many sources of nonlinearities. There are two main types of nonlinearities in a steam generating unit automation control system. First, nonlinearity caused by a control object nonstationarity due to changes of operation modes and changes of object parameters with time. Second, nonlinearities caused by control system elements. Analysis of nonlinearities in steam generating unit automatic control system has been done. Attention is focused on the problem of modelling the actuators and final control element in automatic control systems. Models of saturation, relay with dead zone, backlash, viscous friction and dry friction have been studied. The available models taking into account dry friction data have been analyzed and recommendations as to applying them have been made. Operating data from the Power Block №4 automation control system of the Trypilska thermal power station have been processed. The steam generation unit control parameters of steam and water circuits for the four lines (A, B, V, G) were examined. They are temperature and pressure of steam and water in different points of steam and water circuits and the controller output signals. The relationship of a controlled parameter and time and the relationship of a controlled parameter and the controller output have been examined. Some control contours that may suffer from nonlinearity in an actuator or in a final control element were identified

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Authors: І.О. Ryabenkov, В.О. Andilahay

Theoretical bases of grinding technology researches results form the basis of this work. It has been shown that grinding efficiency increase can be achieved through the use of new kinematic grinding schemes and progressive designs of abrasive tools. However, not enough attention is paid to the calculation of the main tech-nological machining parameters with due regard to separate processes of cutting and friction at grinding, thus restricting the effective application of these kinematic grinding schemes and scientifically grounded selection of optimal processing conditions. In this paper a mathematical model has been developed for determining the material removal rate and cutting force at plunge grinding, what made it possible to substantiate reducing the power strength at grinding and to increase productivity. Calculations revealed that the cutting force at plunge grinding is conditioned by the disk bond friction against the material being processed, the intensity of which in the course of processing time increases proportionally due to an increase of elastic movements in the technological system. Proceeding from these results the optimum grinding conditions based on the use of the abrasive disk that works under self-sharpening conditions, thus eliminating the disk bond friction against the material being processed, have been grounded. In this case, the abrasive disk provides complete removal of the processed material supplied to the cutting zone at the nominal speed of a workpiece movement. Also the ability to reduce cutting forces through the increase of the disk speed and the workpiece speed ratio has been shown

7

Authors: V.P. Kravchenko

The article presents the analysis of two methods of control over hot blast supply into a blast furnace with constant pressure and constant amount (consumption). The analysis of these two methods was performed with the aim of determining their influence upon changes in gas pressure in the blast furnace top. The blast furnace was considered as a unity of vessels (furnace hearth, the top) and gas-dynamic resistance (a column of charge materials). A differential equation was obtained, with regard to the dynamic balance of gas flow at the inlet and outlet of the top; the equation relates the pressure and gas consumption at the top to the pressure and hot blast consumption at the inlet and outlet of the furnace and to the resistance of the column of charge materials. The column of charge materials is considered as n-th number of channels through which gas flow inside the furnace moves and which resist to the flow. By the analysis of this equation at steady state (automatic stabilization of gas pressure in the top), the conditions were obtained to be satisfied with the specified value of gas pressure in the top. This value is equal to a half of the sum of the value of hot blast pressure at the inlet into the furnace and the value of pressure inside the collector of blast furnace gas. This conclusion is verified by the operation practice of blast furnaces in Ukraine. While analyzing the second method of controlling the supply of blast supply-stabilization of consumption (amount) of hot blast supplied into the furnace it has been shown that the method could be realized in condition of stabilization of the amount of blast furnace gas, going out of the furnace. As the resistance of the column of charge materials constantly changes it is necessary to change the hot blast pressure in order to ensure the constant amount of blast, supplied into the furnace. It is often connected with possible substantial pressure fluctuations of hot blast at the inlet of the furnace, which may result in stoppages in the motion of the column of charge materials. Due to it the hot blast pressure stabilization at the inlet of the furnace and the pressure stabilization in the top seem to be the most rational way to control the blast supply

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Authors: G.V. Maslak, O.V. Kiritseva

The article deals with solving an important and relevant problem of enhancing the efficiency of serving production shops by a freight railway station at a large-scale metallurgical enterprise. The process of handling freight railway cars flow at a freight railway station was considered. The main functions of the station, as well as its relations to production shops were identified. The main factors influencing the idle time of freight railway cars, which they spend waiting for loading and transport operations, as well as rolling stock turnout were determined. With the purpose of time factors identification of the railway station operation a graphic model of the handling process (including empty rolling stock arriving, loading, and loaded freight cars departure to the external railway network) was designed. Basing on the results of the research it was determined that the transport operations influence most on the idle time of freight railway cars at the freight railway stations. Analysis shows that operation efficiency of a freight railway station of a metallurgical enterprise depends on proper organization of mutual interaction between transport and freight complexes within the dynamic process of incoming and outcoming freight railway cars flow handling. Obtained data make the basis for further investigation within the framework of solving the problem of enhancing the efficiency of freight railway station operation

7

Authors: A.V. Parkhotko, S.G. Zinchenko

Sequence of operations of seaport work includes a number of operations, dealing with loading, unloading and servicing of ships, reception and shipping freights. Information processing is the cornerstone of material streams management. Information streams of the port cover interaction of internal and external users of information: management of the port, production divisions, public institutions and the clients of the port. Thus, the technological process can be presented as a turn of information streams. Economic efficiency of work of the port depends on the servicing of ships speed. Timely actions of the management thanks to information streams optimum transport accelerate information and documents internal turn and, respectively, minimize unproductive down-time and increase freight turnover of the port. The article deals with the system of information streams of the technological process of the seaport. Information exchange problems within a port have been described. The indicators influencing the data exchange speed in the information system have been defined. The algorithm and functional sense of the management and production sites interaction in organizing loading and unloading has been described. The mathematical model of document flow within the information man-agement system has been made up. The advanced organization of information streams of loading and unloading in the logistic information system of the port has been offered

8

Authors: V.P. Ivanov, Yu.О. Stepnova

Ways to increase efficiency of rolls by enhancing resistance to the formation and development of cracks due to the anisotropy of the working layer properties were explored. The destruction mechanisms of such materials were considered. The possibility of cracks deceleration, due to the layer ruptures or abrupt change of its properties has been marked. It has been shown that the optimum combination of the means braking dislocations provides for a rational metal alloying. The analysis of the rolls of rolling mills service conditions as well as the analysis of types of wear and destruction of products made it possible to formulate requirements on the sur-face layer of the rolls properties. However increase in strength decreases ductility and toughness of the steel. The solution of the problem of the strength and plasticity increase necessitates either methods of metal deep cleaning of contaminants development or significant grain refinement. The part played by structural formations, such as non-metallic inclusions, carbide particles, grain boundaries, etc.in the kinetics of crack propagation has been studied. Since sharp contrast of the properties at the grain boundaries is inconsistent with the requirements of welding technology, the determining factor for making up the working layer is the service conditions. The durability of the roll is determined by allowable wear out of the layer between resharpenings. The correct choice of optimum parameters for the twq adjacent layers - operating and the layer to be maintained is the reserve to improve performance of the roll. The paper has proposed welding-up compositions making it possible to extend the durability due to the optimum ratio of the mechani-cal and thermal properties of adjacent layers. This approach can improve the durability of the deposited products both at the stage of nucleation and at the stage of thermal fatigue cracks growth

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Authors: O.S. Klenov, F.V. Novikov, I.V. Gershikov, О.О. Andilahay

The work deals with the definition of conditions for rational use of the grinding process at the finishing operations, the thermal stress reduction due to the establishment of optimal grinding conditions and characteristics of the abrasive disk, the application of new kinematic grinding schemes and elimination of intense friction of the disk bond with the material being processed which is the main source of temperature defects on the surface being processed. A mathematical model for determining the temperature of cutting at grinding with due regard to temperature change laws in the allowance layer being removed for definite depth of heat penetration into the surface of the workpiece has been developed. A problem in cutting infinitely thin adiabatic rods (thought of as the allowance to be removed) with an abrasive disk, a new analytical dependence for determining the cutting temperature with regard to contact time of the abrasive disk with the adiabatic rod was obtained. It has been shown that a 10 times decrease in conventional cutting stress resulted in proportional maximum cutting in temperature reduction during grinding, it corresponding to the practical data. Knowing the cutting temperature change dependence on adiabatic rod heating time, cutting temperature for any grinding scheme can be determined, the contact time of the grinding wheel with the adiabatic rod can be set as well as the speed of the heat source movement speed along the adiabatic rod. Examples of cutting temperature calculation for the specific conditions of grinding have been given. It was found that in the course of time the temperature of cutting at grinding increases continuously, approaching the value of the energy balance, that is equal to the ratio of the conventional cutting stress to the specific heat multiplied by the density of the material being processed. The terms of the cutting temperature reduction at grinding have been laid out and practical recommendations have been made

8

Authors: G.V. Maslak, P.M. Nosenko

The article deals with the operation analysis of a metallurgical enterprise transport system with one railway siding connected to the external network. Three functional modules were determined: transport complex for incoming wagon traffic processing, transport-and-handling complex for raw materials unloading, transport-and-handling complex for finished products shipment. For each of the complexes basic functions were determined: the first module distributes empty and loaded waggons between the freight railway stations within the enterprise; the second module provides timely supply of production shops with required volumes of raw materials; the third module enables timely supply of production shops with railway rolling stock for finished products shipment. Structuration of overall volume of transport operations has been conducted for each of the complexes within the transport system of the metallurgical enterprise, basic technological operations have been determined, and causes for time waste have been found out. Overall volume of transport operations per day has been determined, it comprising planned transport operations and extra transport operations as well. As a result of the research it has been determined, that maximum volume of extra transport operations occur at the transport complex for incoming wagon traffic processing. Its operation is based on time norms which not always fit the dynamics of external network operation, as well as production shops operation. Furthermore, this module is a connecting link making the dynamics of external waggon traffic, the internal dynamics of the enterprise, and the dynamics of production shops compatible. As a consequence, considerable extra time waste occurs when waggon traffic goes through this module

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Authors: V.G. Gavrilova, M.V. Pomazkov, N.E. Karavaieva

The work presents an analysis of applying various steels for manufacturing motor-car bodies. There is a brief description of cold-rolled sheet steels RRST 1405 produced according to the standards DIN 1623 and DIN 1541; UST 1203, UST 1303 according to DIN 1624 and DIN 1606; ST 4, 08MnSiAlTi, 07MnNbAl and also a classification and a brief description of steels made according to USLAB: IF-steel with increased formability, thermo-strengthened BH-steel, dual phase (DP) steels, transformation induced plasticity (TRIP) steels, martensitic (Mart) steels, austenitic high-tensile steels – (TWIP) steels, high strength steels of new generation of AHSS type (advanced high-strength steels) and UHSS (ultra high-strength steels), high-strength steels and superplastic steels of new generation for lightweight constructions (TRIPLEX-steel), hot-rolled nano-structured steel NANOHITEN. It has been shown that the main tendency in modern approach to engineering and manufacturing sheet steel used in automotive industry is to increase strength while maintaining formability characteristics, reducing the coefficient of normal plastic anisotropy (Lankford value ratio), as well as increasing srengthening at deformation. The advantages and disadvantages of the materials used in the automotive industry have been shown, as well as ways of their improving. The work represents a compilation of several publications. The materials can be used for developing a training course «Materials to be used in transport» within the framework of the International Project on reforming curricula TEMPUS «MMATENG»: «Two-stage Training Program for Engineering Materials Curriculum Modernization»

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Authors: О.M. Skrebcov, A.V. Fedosov, D.V. Paschuk, A.S. Kachikov

Based on the analysis of the extensive literature a mechanism for the formation and development of transverse cracks on the surface of slab billets of cast peritectic steels has been displayed. Hot cracking of the complex properties of cast steel - crystallization temperature range, the casting shrinkage, strength and ductility at high temperatures. Pequliarities of steel ingots peritectic solidification in the crystallizer can give rise to a number of weakened localities(«healed» hot microcracks «hooks», metal in the form of coarse oscillation marks), which in their turn act as nucleation transverse cracks nucleation. Analysis of the various mechanisms of the formation of the transverse surface cracks made it possible to offer a series of recommendations to reduce the probability of fracturing: a) to optimize the chemical composition of the steel in order to obtain the lowest possible temperature end δ-γ conversion in the range of existence of the single-phase austenite region existence, b) to minimize the content of harmful impurities (sulfur phosphorus, nitrogen, non-ferrous metals) in the molten steel and alloying elements, the presence of which negatively affects the mechanical properties of the steel at high temperatures; c)to provide a stable heat removal from the crust of the ingot that does not make it possible to form coarse macrogranular structure; g) to provide the conditions for the formation of large inclusions and uniform distribution in the matrix metal; d) to prevent deformation of continuous casting at temperatures with lower plastic properties

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Authors: R.V. Vlasenko, O.V. Bialobrzeski

Electricity quality improving is extremely relevant nowadays. With such industrial loads as induction motors, induction furnaces, welding machines, controlled or uncontrolled rectifiers, frequency converters and others reactive power, harmonics and unbalance are generated in power grid. Reactive power, higher harmonic currents and asymmetry loads influence the functioning of electric devices and electrical mains. An effective technical solution is the use of new compensating devices, that is active power filters. The emergence of consumers with a unit capacity of four wire networks requires a new approach to building system control active power filter. When designing the active power filter control system the current flowing in the neutral wire must be taken into account. To assess the power balance in the four wire active power filter, scientists have proposed to apply pqr theory of power based on the Clarke transformation. There are different topologies of three-phase four wire active power filters. A visual simulation of Matlab / Simulink model with an active power filter based on pqr theory of power has been created. A method of pulse width modulation with four control channels was used as pulses forming systems with transistor keys. Operating conditions of three-phase four wire active power filter with asymmetry, non-sinosoidal voltage source and asymmetric load have been studied. The correction taking into account the means improving the active power filter has been offered as pqr theory of power does not take into account non-sinosoidal voltage

11

Authors: О.О. Koifman, О.І. Simkin

An issue of improvement of the effectiveness of the operation of a block of hot blast stoves of the blast furnace in order to rise the temperature of the blast-furnace air was considered. It was shown that an increase of the temperature of the blast-furnace air without the use of natural gas and oxygen for combustion is possible due to the changing of the operation modes of a block of hot blast stoves and at the increase of the pressure of the exchange gas. An analysis of the recent researches and publications describing the methods for determining the parameters of the operation of the block of hot blast stoves of the blast furnace was performed; their advantages and disadvantages were described. The goal of the research was set. A database of process parameters of the block was processed to determine the main characteristics of the operation of hot blast stoves of the blast furnace. Averaged values of the basic technical and design parameters were obtained; they characterize the operation of each hot blast stove of the block with the use of which the adjustment of a mathematical model of the operation of each of hot blast stove of the block was achieved. A method for determining the main unit operating parameters on the block on the account of the desired blast temperature was designed. The values of the duration of the cycle "heating + air blasting" depending on the set-point temperature of the smoke at various values of air blasting temperatures were determined for each hot blast stove of the block using a mathematical model. The authors suggested to use such dependencies to determine the temporal parameters of the operation of the block of hot blast stoves. The obtained values of the duration of heating periods and air blasting of each hot blast stove of the block should be corrected if the continuity of the air blast supply to the blast furnace is not ensured. The examples of the use of this technique were given and the obtained results were described. It is shown that an increase of the pressure in the operating space in the course of the heating period of the checker the temperature of the hot air blasting can be increased due to a larger amount of heat accumulated by the checker. As seen from the results of the research the set blast conditions of the blast furnace can be ensured with fewer hot blast stoves in the block due to the increase of the pressure