Key Engineering Materials Vol. 836

Abstract: The study solved the problem of determining the technological mode of operation of the device for loading solid lumpy and granulated sulfur into a melting bath with molten liquid sulfur. For this it is necessary to solve two main problems: to determine the method of loading solid sulfur into the melt, to calculate the main design and technological parameters to ensure the required performance of the smelting bath. As a result of experimental studies, the mode of operation of the loading device was obtained, during which the partial melting of the surface of sulfur particles in the surface layer of the melt occurred. This led to the adhesion of particles to each other, the formation of conglomerates having a size that is much larger compared with that of particles of the initial particle size distribution. As a result of this phenomenon, the melting rate and the melting bath were significantly reduced, filled with a solid phase. As a result of the study, a model was developed and the problem of calculating the limiting modes of the loading device operation was solved for preventing solid particles from sticking together.

Abstract: In this article, we present our developed and manufactured centrifugal casting machine. We present the results of mechanical testing of samples from polymer composites made on it. At the beginning we give an overview of the main trends in the market of polymer composites. We consider the main factors affecting the mechanical characteristics of polymer composites, and determine the main limitations of using centrifugal casting technology for polymer composites. In conclusion, we give directions for further research. Many industries use polymer composite materials (PMC) to meet production needs. The main advantage of PMC is the possibility of obtaining high strength with relatively low weight, as well as the possibility of obtaining additional necessary properties, such as dielectric, magnetic, etc. The PMC market continues to grow, and now PMC is widely used in aircraft manufacturing, automotive, medicine, etc. [1]. Despite the positive aspects of using PMC, this method has some drawbacks. Firstly, low automation of the process of casting parts from PMC. Many technologies are quite difficult to automate due to their process complexity and constant monitoring. Development in this direction is already underway, and there are practical solutions, such as automatic tape placement (ATL) / automatic fiber placement (AFP) [2]. On the other hand, the cost of these solutions is quite high. Secondly, the high cost of the equipment and tooling manufacturing. Such technologies as pressing, pressing and autoclave molding using prepregs are attached to certain technological equipment and need to organize pressure, maintain temperature, etc. This increases the range of equipment used and overall process complexity. In some technologies using high pressure and heat-cooling such as pressure casting (RTM) [3], it is necessary to use high-strength steels for molds, the processing of which takes a long time and wears the tool. Thirdly, increased knowledge-intensive work and high requirements for staff qualifications [4]. Manufacturing products from PMC requires careful monitoring by the technologist, since the influence of such parameters as: temperature, pressure will affect on the product structure and, accordingly, its characteristics. Fourthly, loss of strength after cutting operations (such as drilling, milling, taping and so on) and further stratification of PMC [5]. This leads us to the fact that used technology should maximally ensure the product geometry with minimization of subsequent post-processing.

Abstract: The physical and chemical properties of "loose" manganese ore of Ulu-Telyak Deposit of the Republic of Bashkortostan for the possibility of its use as an effective sorbent for purification of exhaust gases of metallurgical, chemical, oil refining, mining and other industries are studied. Analyses were carried out on the phase composition, chemical composition, determined the specific surface area of the pores and thermogravimetric method of water content. The process of sorption of a gas mixture containing hydrogen sulfide, methyl and ethyl mercaptans was also studied. The results of the experiments concluded that the prospects of using this "loose" manganese ore for the sorption of sulfur-containing gases.

Abstract: The study of the effect of Elongated Cumulative Charges (ECC) on rock formations has an important scientific and practical significance for solving a number of process problems in mining practice. The use of charges with a longitudinal concavity for a directional destruction (presplit blasting, “smoothwall” chipping) involves reducing the explosives consumption, preserving the aquifer rock mass from additional explosion-caused cracks, obtaining a smooth contour and reducing the volume of drilling works. It is noted that one of the options that provides the explosion energy redistribution in a destructible medium is the use of elongated cumulative charges with a damping core. Experimental evidences on the dynamic loading of model blocks by an explosion of an elongated cumulative charge with an inert pad of various acoustic stiffness are reported.

Abstract: The article is devoted to the analysis of the composition and properties of the materials and liquids during transportation using pipeline and shows that in order to increase the efficiency of hydraulic transport systems in mining a transition to the transportation of slurries with a high concentration of solids in the slurry flow is necessary. Experimental studies have shown that slurry tailings of gold-containing ore with mass concentrations of more than 55 % are viscoplastic fluids. Experiments on a rotational viscometer allowed us to establish the main rheological characteristics of the studied slurries – shear stress and the dynamic effective viscosity. It has been established that over the entire range of concentrations from 55 to 65 %, the flow of slurries is described by the Bingham rheological equation. Experimental studies of hydraulic transport performed on a laboratory setup with a pipeline diameter of 50 mm confirmed the results obtained on a rotational viscometer. The curved of mixture stream is inclined straight lines that are cut off on the axis of the head in the sections, which determine the initial hydraulic slope corresponding to the yield shear stress on the rheological curves. According to the results of the experiments, a method has been developed for calculating the hydraulic transport of high concentrated slurries of tailings of gold-bearing ore. Calculations showed that in a given range the performance of the hydrotransport system and the mass concentration of the solid phase pressure losses vary from 11 to 84 m of water column/m. Head loss values increase with the increasing concentration. A sharp increase in the head loss occurs in the concentration range from 60 to 65 % and higher.

Abstract: The article discusses the modern method of increasing the corrosion and wear resistance of machine parts by diffusion saturation from the environment of fusible melts. A review of ongoing studies is on the multicomponent diffusion saturation of steel samples, including refractory metals. The results of the studies will be the basis for the formation of a coating with increased resistance to corrosion and strength of the surface layer.

Abstract: Development of an optimal technology of heat treatment for blanks of the casing pipe made of steel 40H (GOST 4543) is used in the oil and gas industry for casing. It is accompanied by quenching in various environments to ensure guaranteed obtainment of the required mechanical characteristics. These characteristics are specified in GOST 632-80 and met in order to improve the properties of the 40H steel.

Abstract: Commonly used Grade 20GL cast steel has unstable impact strength values determined on V-notched samples at –60 °C and so cannot provide reliability of cast parts at negative temperatures.

Abstract: The paper considers applications of carbon materials as carriers of biologically active substances. The atomic layer deposition method allowed chemically synthesizing surface-modified composite materials based on graphite and carbon fibers, which maximally preserved the activity of enzymes and biologically active substances. It is shown that the activity of a biologically active substance depends on the chemical composition and state of the surface of carbon-based carriers.