Analysis of the mixing efficiency of the components of the iron-phosphate mixture in the dry state

The results of researches of influence of time of mixing of initial components in a dry condition on degree of assimilation of iron-containing component of forming and core iron-phosphate cold-hardening mixes are presented. The percentage of assimilation of the dispersed iron-containing component after each minute of mixing in laboratory runners with a total mixing time of 15 minutes was determined experimentally. Using the original method of particle separation, under the microscope were separated scale particles that were not assimilated (not distributed on the surface of the sand), and weighed them. The dependences of the degree of assimilation of the metal component of the iron-phosphate mixture on the mixing time at different initial contents are obtained. It is shown that the highest degree of absorption of the iron-containing component of iron-phosphate mixtures is achieved by mixing the components of the mixture for the first four to five minutes. Then this figure begins to decrease as the grains begin to collapse under the action of the rolls of the runners, and the forces of electrostatic interaction between the surfaces of the grains and the dispersion medium are reduced compared to the forces of mutual gravity between the dispersed particles of iron-containing component of the mixture. Based on the analysis of theoretical positions and the results of experimental studies, the assumption is made about the possibility of adjusting the conditions and parameters of solidification of phosphate binder systems, in particular using iron-containing filler of a certain dispersion and mixing the components in the dry state for some time. It is known that for mixing the components and assimilation of the required part of the iron-containing component of the mixture uses a significant amount of energy (depending on the type of unit used). To reduce the energy consumption of this process, the urgent task is to determine the degree of assimilation of the iron-containing component of phosphate cold-hardening mixtures in their manufacture by mixing the components in the dry state. Keywords: iron-phosphate cold-hardening mixture, mixing in the dry state, interaction, adhesion, experiment, research, dependence

Analytical method of calculation of thermal fields of cast parts during crystallization

The aim of the work is to create a mathematical method that allows to calculate the distribution of thermal fields in cast parts during crystallization using a system of analytical formulas. During the calculations, a combination of known analytical formulas GF was used. Balandin, AY Weinik, S. Schwartz with their own original mathematical solutions created on the basis of the analysis of thermophysical processes in castings in the process of their crystallization. Computer simulation of thermal fields using the LVMFlow program was used to compare the results. According to the created mathematical method, examples of calculation of thermal fields for two castings made of steel 25L of hollow cylindrical shape, the wall thickness of which is 100 mm and 4 mm, respectively, are given. Calculations were performed for the conditions of crystallization of castings in a single sand form. The comparison of results of calculations by the developed method and with use of the existing software is presented. For the first time, based on our own mathematical and thermophysical developments, a comprehensive calculation method for determining the thermal field of the casting during crystallization and cooling was developed. casting. The technique is expressed in a number of analytical formulas, each of which describes a specific thermal process that occurs in the casting. This takes into account the features of the casting configuration. The created complex method of calculation of thermal fields of cast parts is a mathematical basis for determining the thermal fields of molds and rods, which allows to predict their properties and select the optimal molding materials. The created technique can also be offered as a mathematical basis for refining applied computer programs for foundry production. CASTING, TEMPERATURE, THERMAL FIELD, COOLING DYNAMICS, COOLING DURATION, MATHEMATICAL LAW, COLORING FRONT, CALCULATION

Sand-sodium-silicate mixtures grains composition optimization for structuring by steam-microwave solidification method

Mixture sizes of sand-sodium-silicate conglomerates and sodium silicate solute content in them influences on the basic physical and technological indicators of molding and core mixtures structured in steam-microwave environment have been investigated. Sand-sodium-silicate mixture structured by steam-microwave environment (steam-microwave solidification method – SMS-process) composition has been optimized. Standard and generally accepted methods and techniques of molding mixtures investigation have beenused in this study. For mixtures manufacturing have been used: quartz sand brand 1K2O202; sodium silicate solute with silicate modulus of 2.8…3.0 and specific gravity of 1.42…1.44 g/cm3. Quartz sand cladding has been implemented with 0.5 and 2.5% sodium silicate solute (by weight, over 100% sand). Sand-sodium-silicate conglomerates have been scattered in sieves and conglomerates with sizes less than 0.315mm and with sizes from 0.315 to 0.63mm have been used for research. Mixture composition has been optimized according to results of simplex planning and experimental data by simplex triangles constructing and superimposing their formatted images on each other with darkened fields between isolines that do not meet of each parameters required level. To plot simplex lattices, model with simplex lattice plan of incomplete cube in Scheffe’s triple system has been used. For the first time, influence of mixture sand-sodium-silicate conglomerates sizes and sodium-silicate-solute content in them on basic indicators of mold and rod mixtures structured in steam-microwave environment has been established, and their composition has been optimized. Data obtained will be useful in molds and rods structured by SMS-process manufacturing. They will have predictable indicators of properties that correspond to their allowable level. Optimal composition of sand-sodium-silicate mixture, structured by SMS-process, is mixture of quartz sand, part of which passed through sieve with cell of 0.315 mm and have sodium silicate solute content (МSiO2=2.8…3.0, 2=1.42…1.44 g/сm3) in amount of 1.5% (by weight, over 100% quartz sand). Keywords.Sand, silicon silicate solute, steam-microwave solidification, optimization, conglomerates, strength, gas permeability, crushability, density, beam deflection, knockout energy.

Analysis of hydrogen behavior by crystallization of secondary aluminum alloy

Methodology. There was conducted the process modeling of hydrogen by crystallization of secondary aluminum alloy. Findings. There was conducted an analysis of hydrogen behavior by indurating secondary aluminum alloy castings. There were obtained expressions for calculation of the current value in the process of secondary aluminum alloy crystallization of the hydrogen density in the boundary diffused layer, on the crystallization front, in the volume of the remaining melt, and the effective hydrogen distribution coefficient. Originality. For the first time, there was obtained an arithmetic model for the forecasting of hydrogen behavior by indurating secondary aluminum alloy castings. Practical value. The results of the study can be implemented with the purpose of the flow optimization process and the more efficient use of expensive equipment for getting high-quality secondary aluminum alloy castings. Keywords: aluminum, secondary aluminum alloys, indurating, hydrogen, crystallization front, distribution coefficient, boundary diffusion layer.

Analysis of experience in the use of corrosion-resistant tubing in gas wells and research the efficient of corrosion inhibitors

Purpose. Analysis of the efficient of corrosion inhibitors in the natural gas extraction on Lutsenkivske gas condensate deposit wells has been carried out. Methodology. Electrochemical measurements were obtained in 3% NaCl. All potentials were measured versus SCE. Potentiodynamic polarization curves were obtained at the scan rate of 0,2 mV/s. Findings. It has been established that inhibitors of SE-231-K and ACL-060 brands are effective for protection of corrosion-resistant pump-compressor pipes against corrosion in the aggressive environment on Lutsenkivske gas condensate deposit wells. Originality. For the first time, the analysis of the effectiveness of corrosion inhibitors in the form of sticks in the packer wells of the Lutsenkivske gas condensate deposit wells. Practical value. The results of the work will be used in the corrosion protection of packer wells of the Lutsenkivske gas condensate deposit wells. Keywords: pump and compressor pipes, gas wells, corrosion, inhibitors, corrosion protection

Improvement of quality and improvement of technology of production of economic alloyed steels for power engineering

Purpose. Investigate the effect of complex microalloying with nitrogen, titanium and aluminum on the structure and properties of cast steels at elevated temperatures. Methodology. Methods of optical microscopy were used for metallographic analysis of the microstructure of steels. The mechanical properties at room and elevated temperatures were determined for static tension, crease and impact bending. Results. The technology of carbonitride strengthening of silicon-manganese production steels has passed pilot testing. The results of mechanical tests indicate a favorable complex effect of nitrogen, titanium and aluminum on the properties of 20GSL steel in the entire range of operating temperatures. Scientific novelty. For the first time, the effect of nano-dispersed carbonitride phases (TiN, AlN) on the mechanical properties of low-alloy silicon-manganese steel of the GSL type at elevated temperatures (250-4500C) has been investigated. Practical value. The use of carbonitride technology for strengthening silicon-manganese heat-resistant electric steel provides an increase in operational reliability, an increase in the service life and reduce the metal consumption of equipment for power engineering. Keywords: technology, electric steel, heat resistance, carbonitride reinforcement, microalloying, steel 20GSL.

Approaches to solving problems of practical application of magnetic-coercive control in the assessment of the state of crane metal structures

The aim of the study. By taking into account the individual characteristics of magnetic structuroscopes such as KRMCC-2M to increase the reliability of the passport of magnetic control. Research methodology. To take into account the individual characteristics of magnetic structuroscopes such as KRM-CC-2M, a method has been developed. It is based on taking into account the individual characteristics of magnetic structuroscopes. The essence of this method is that together with the crane and PMK you need to have a stepped pattern with different sections of the same material from which the metal structure of the crane. At each magneto-coercive NC of the metal structure of the crane it is necessary to measure the coercive force of this sample and enter them in the PMC together with the serial number of the structroscope. Having readings of the coercive force on this sample of all structuroscopes of the KRM-CC-2M type, it is possible to draw a conclusion about the level of magnetization intensity of each structroscope. Next, calculating the difference in the intensity of magnetization of the devices KRM-CC-2M (ΔNS δ, A / cm), take it into account when processing and analyzing the results already obtained on the crane magnetic-coercive NC. Results. The process of analysis of the results of magnetic coercive control is automated. It is shown that it is impossible to be limited at an estimation of a condition of a metalwork to only one method. For a more objective result, it is necessary to apply magnetic coercive control in combination with other control methods and calculation methods. Work on magneticcoercive non-destructive testing, which solve existing problems, has been confirmed in practice. This will make it possible to conduct magnetic-coercive control of metal structures with different thicknesses of elements, take into account the individual characteristics of magnetic structuroscopes such as KRM-CC-2M and increase the coercive force depending on the load intensity of the metal structure. Practical significance. The results of the research are used in the analysis of the change of coercive force in the bevel of the sprung system of the crane-loader with a capacity of 32 tons.

Investigation of the movement of charge materials in the tray-distributor of the cone-free loading device of the blast furnace

Objective.Determine the analytical dependence of the profile of granular materials moving on the tray-distributor of the cone-free loading device on the length coordinate. Method. Kinematic and geometrical regularities of movement of charge materials on the distributive body of the cone - free loading device of tray type are considered. It is shown that the dynamics of the flow of charge materials is significantly influenced by such factors as the value of the average particle diameter of the loaded material, physical and mechanical characteristics of the charge, its flow rate, angular velocity of the distributor tray and its angle. Results. The analysis of the obtained results makes it possible to calculate with sufficient accuracy the rate of charge rise from the tray-distributor in the furnace space of the blast furnace. This makes it possible to calculate the trajectory of the charge flow in the furnace space and to obtain the coordinate of the intersection of the trajectory with the surface of the charge backfill on the blast furnace grate. The obtained equation of the profile of the movement of charge materials on the tray-distributor makes it possible to recommend the position of the tray when loading the blast furnace, which prevents the transfer of the charge through the edge of the tray. Scientific novelty. A new method for solving the Cauchy problem for a differential equation describing the flow of a charge through a distributor tray is proposed. It is established that the change in the flow rate of charge materials passing through the tray-distributor significantly affects the configuration of the surface of the charge on the tray, and this, in turn, causes a change in the rate of flow into the furnace space. Studies have shown that the motion parameters are significantly affected by the initial height of the charge materials on the tray. Practical significance. The obtained results allow analytical calculation of the change in the dynamics of the charge movement under the condition of a constant angle of inclination of the tray of the loading device of the blast furnace. This makes it possible to expand the possibilities of automatic correction of the gas dynamics of the blast furnace zone in specific charge conditions.

Solid phase reaction between components of the charge in the areas burning solid fuel and features of formation liquid phase

Objective. The influence of solid-phase reactions in the agglomerated charge layer on the quality of manganese ag-glomerate is considered. Research methodology. Thermodynamic analysis was used to establish the predominance of reactions. The phase (mineral) composition of manganese concentrates and the experimental agglomerate was investigated by X-ray diffraction method on a DRON-2 diffractometer in monochromatic Cuα radiation. The interplanar distances at the corresponding values of the X-ray reflection intensity from the investigated samples of concentrates and agglomerate were determined by comparing the obtained data with the corresponding tabular data given in the reference books on X-ray diffraction analysis of substances. Sintering of the experimental agglomerate was performed on a laboratory agglomeration bowl. Research results. It is established that the dissociation of higher manganese oxides begins at relatively low temperatures and proceeds in stages to the formation of MnO. Since the chemical affinity of manganese for oxygen is significant, reduction to metallic Mn was not observed, as this requires a high content of reducing agent and a reducing atmosphere, which is difficult to achieve in real agglomeration processes. Dissociation of rhodochrosite carbonate concentrate and gradual dissociation of dolomitized limestone leads to an increase in CO2 content in the atmosphere. Slag bonds are represented by compounds Mn2SiO4, MnO • Al2O3, Mg2SiO4, CaO • MgO • SiO2, 2CaO • SiO2. Thermodynamic calculations show that at moderate temperatures, compounds such as calcium ferrites are not formed, which is likely for the interaction between basic flux oxides and manganese oxides. Scientific novelty. Studies have shown that CaO does not completely convert to a slag bond, and even with a basicity of order 1, there is undigested lime. White spots are formed in the structure of the finished agglomerate. Such an agglomerate during transportation and storage loses strength and a large amount of trifles is formed..

Modern electroslag technologies of electrode remelting and processing of liquid metal (review)

Objective. The results of the analysis of advanced technologies of electroslag remelting are presented. Results It is shown that ESR today is the main and most challenging in obtaining of high quality metal. Protection of the melting chamber and the electrode from the atmosphere by inert gas (IESR) or melting under pressure (PESR) prevents oxidation, which is especially important during remelting of the steels and alloys with high content of easily oxidizable elements. Refusal to use a consumable electrode in the classical ESR in favor of liquid metal, provided by the use of current-suppling mold, is an effective solution to the problem of its manufacture (manufacturing price reaches 40-60% of the cost of ingot production, and in some cases impossible) and reduce energy costs. Scientific novelty. During ESR LM, there is a decrease in temperature of slag and overheating of metal in comparison with classical ESR , the volume of liquid metal bath decreases that followed by improving conditions of ingot formation, at the expense of decrease in development of segregation processes and gives the chance to receive metal of homogeneous composition and structure. Practical significance. The advantages of the new ESR processes are a wide variation of the metal feed rate, less metal overheating and a flat bath, which provides molding with a homogeneous and defect-free internal structure and a smooth surface.