The paper presents a comprehensive study of the physicochemical properties of various types of chrome raw materials from Kazakhstan: chrome ore, chrome concentrate and chrome dust (CD), which is a waste product of gas cleaning systems in ferrochrome production. A comprehensive study of the chemical and phase composition, morphology and elemental heterogeneity of the materials under study was carried out using chemical analysis, X-ray phase analysis (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). It was shown that chrome ore is characterized by a high content of Cr₂O₃ and MgO with a significant proportion of silicate impurities, chrome concentrate is enriched in chromium oxide and has a minimum content of SiO₂, and chrome dust contains a reduced amount of chromium and an increased content of silica and silicates. XRD revealed the presence of spinel phases (MgCr₂O₄, FeCr₂O₄) and Cr and Fe oxides, and SEM-EDS showed pronounced zonal chemical heterogeneity, especially in dust waste. The obtained results allow us to estimate the metallurgical value of the studied raw materials and justify the feasibility of recycling chrome dust in the technological cycle of ferrochrome production.

https://doi.org/10.48081/BGQF2235

2026

Issue 2

The main problems of producing castings by the Lost Foam Casting (LFC) method are as follows: – carburization of the surface layer of steel castings during the burnout of the polystyrene model; – the high cost of foundry polystyrene used as a model material. This significantly increases the cost of the final products and limits the widespread application of the LFC method in manufacturing. In global practice, construction polystyrene granules are not used for producing models in LFC. However, previous studies have demonstrated the possibility of using them as a component of the model material. In addition, controlling the structure, and therefore the properties, of the resulting castings presents certain challenges. The ability to obtain castings with a fine-grained (high-strength) structure and a homogeneous composition throughout the entire volume of cast billets can be achieved by regulating the thermal regime of castings, for example, by combining suspension casting with the lost foam casting method. To introduce inoculants into the melt, the polystyrene model itself is directly used. The foundry is the most important procurement base of mechanical engineering. A variety of shaped castings are produced by casting, which are obtained by filling casting molds with liquid metal. During solidification, the metal takes on the shape of the cavity of the mold into which it was poured. Cast products are widely used in industry, as the sizes and shapes of castings often approach the required sizes and shapes of finished products to a greater extent than blanks obtained by other methods. This is a very important advantage, as reducing the cost of machining reduces the cost of products and reduces metal consumption. In addition, the production of cast blanks is much cheaper.

https://doi.org/10.48081/BGQF2236

2026

Issue 2

Hydraulic valves are integral components of hydraulic drive systems, performing the functions of regulating the flow rate and direction of the working fluid. Among them, proportional spool-type directional control valves stand out due to their high control precision and reliability, which ensures their widespread use in both industrial and mobile applications. However, one of the key challenges in their design remains the flow forces generated by the momentum exchange of fluid in the control orifices. These forces can cause undesirable spool deviations, reducing system stability, control accuracy, and energy efficiency. This study presents a theoretical and geometrical analysis of flow forces in proportional spool valves, aiming to transform them from a disturbing influence into a useful control parameter. A modified spool geometry is proposed that maintains an almost constant flow force throughout the entire stroke range. The effectiveness of the proposed approach is validated through analytical calculations and numerical simulations. The results obtained can be applied in the design of next-generation energy-efficient and high-precision hydraulic systems.

https://doi.org/10.48081/BGQF2213

2026

Issue 2

The article considers the use of heat-resistant and wear-resistant materials for internal combustion engine components in a hybrid vehicle. In such engines, the service life of a part is not determined only by its strength margin. Under real operating conditions, friction, heating, changes in clearances, surface quality, and frequent transitions between engine operating modes act at the same time. Therefore, the study focuses not on one parameter, but on several indicators that are closer to actual operation: friction coefficient, temperature resistance, thermal deformation, and estimated service life. Steel 40Kh, titanium alloys, Al₂O₃ ceramics, and Ni–SiC coatings were selected for comparison. Steel 40Kh was used as a basic reference material for comparison. Titanium alloys were considered from the standpoint of reducing the mass of parts, ceramics as a material for high-temperature zones, and Ni–SiC coatings as a protective layer for friction surfaces. The study used published data, simple calculation relationships, and simulation in ANSYS and SolidWorks. The obtained results show that the most practical approach is not the complete replacement of conventional materials, but their selective application according to load zones. With this approach, the estimated service life of ICE components may increase by about 30–35%. At the same time, these values require verification on a real engine or an engine test bench, since service life strongly depends on coating technology, lubrication, cooling, and operating conditions.

https://doi.org/10.48081/BGQF2241

2026

Issue 2

This article discusses in detail the design features of piston rings-the most important element in the structure of the cylinder – piston group, which is the main unit of internal combustion engines, their condition in operation and the impact on the energy, environmental and mechanical efficiency of the engine as a whole. In the course of the study, the main functional types of piston rings were analyzed: compression, oil-removing and double combined, and the influence of their geometric shape (barrel-shaped, conical, rectangular profiles), configuration of the side surface and modification of the contact surface on the degree of sealing and friction in the cylinder area was described. The influence of various materials used on the reliability of operation is shown: cast iron, alloy cast iron, steel-based rings and their wear-resistant coatings: chromium, molybdenum, nitride, plasma. At the same time, the results of a patent study of modern versions of compression rings were analyzed. Innovative solutions on the world's patent databases include thickness changes, special grooves that reduce thermoelastic deformation, low-friction concreting technologies, crack optimization, and design innovations that increase gas tightness. The analysis showed that an important role in improving the efficiency of internal combustion engines is played by improving the design parameters of piston rings. The main purpose of the scientific work is to identify ways to reduce friction and wear by optimizing the design of piston rings using modern materials and engineering methods, increasing the life of the cylinder-piston group and increasing the energy efficiency of the engine.

https://doi.org/10.48081/BGQF2245

2026

Issue 2

The low hardness of copper alloys used as the material for continuous casting molds makes them susceptible to plastic deformation, wear, and high-temperature oxidation. This leads to premature degradation of working surfaces and the formation of defects on the cast billets. In this study, the microstructure, phase composition, mechanical, and tribological properties of Cr₃C₂–NiCr coatings deposited by high-velocity oxy-fuel (HVOF) spraying onto copper substrates used in casting molds were investigated. The relevance of this research is driven by the need to increase the service life of copper molds in continuous steel casting processes. It was established that the HVOF spraying parameters significantly affect porosity, coating thickness, microhardness, and the tribological behavior of the coatings under conditions simulating contact between the billet and the working surface of the mold. Among the investigated regimes, the coating deposited at a powder feed rate of 11.39 m/s formed the densest lamellar structure and demonstrated the highest microhardness. Tribological tests showed that this coating exhibited the lowest coefficient of friction, whereas the other samples were characterized by higher porosity and poorer wear resistance. The obtained results highlight the importance of optimizing HVOF spraying parameters for the development of wear-resistant protective coatings capable of operating effectively on copper molds subjected to severe thermomechanical loads during steel casting.

https://doi.org/10.48081/BGQF2231

2026

Issue 2

An earthquake simulator is a device for simulating ground motion during an earthquake and is designed to generate seismic waves. The earthquake simulator is used by emergency response personnel to conduct seismic training and to train them to respond to a real earthquake. At least hundreds of millions of people worldwide are at significant risk of catastrophic seismic damage. This problem is particularly acute in Almaty, where the last earthquake in the spring of 2024 caused panic among people and demonstrated a complete lack of preparedness for how to react and behave during an earthquake. Earthquakes pose a danger and risk to everyone, and everyone should be aware of the appropriate knowledge and protective measures. This study developed and manufactured a prototype earthquake simulator for training human behavior during earthquakes. This simulator is based on a flat parallel rope robot that simulates a real earthquake based on a given earthquake seismogram. The earthquake simulator, based on a planar cable parallel robot, performs translational single-axis movements in the X or Y direction. Experimental studies of the prototype earthquake simulator, based on a planar cable parallel robot, confirmed its ability to reproduce a given seismogram.

https://doi.org/10.48081/BGQF2216

2026

Issue 2

The paper presents the results of a comprehensive study of wear and corrosion resistant oxide coatings based on Al₂O₃, obtained by air-plasma spraying, designed to increase the service life of pumping equipment parts operating in aggressive and abrasive environments. Austenitic stainless steel 10Kh18N9, widely used in chemical and power engineering, was used as the substrate material. The main focus is on studying the influence of plasma arc current in the range of 300–500 A on the formation of microstructure, phase composition, porosity, as well as mechanical, tribological and adhesive characteristics of sprayed coatings. It has been shown that increasing the spraying current promotes more complete melting of Al₂O₃ powder particles, improves their flattening upon impact with the substrate surface, and forms a denser and more uniform coating structure with reduced porosity. It has been established that with an increase in the plasma arc current, an increase in the adhesive strength and microhardness of the coatings is observed, as well as a decrease in the coefficient of friction and wear intensity under abrasive conditions. The most favorable combination of high wear resistance, adhesive strength and structural stability of coatings is achieved with a spraying current of 500 A. Corrosion tests in aggressive environments have shown that the application of Al₂O₃ coatings does not have a significant negative impact on the corrosion behavior of 10Kh18N9 steel and does not reduce its corrosion resistance. The obtained results confirm the potential of using air-plasma oxide coatings based on Al₂O₃ for the protection and strengthening of pumping equipment parts operated under conditions of intensive wear and corrosion.

https://doi.org/10.48081/BGQF2226

2026

Issue 2

When processing copper-molybdenum ores, the main objective is to extract copper at the initial stage of enrichment using bulk-selective flotation. This prevents overgrinding and loss in tailings. The aim of this study is to improve copper-molybdenum ore processing technology by establishing optimal parameters for copper and molybdenum extraction during bulk flotation with the extraction of the total mass of sulfides (copper + molybdenum + pyrite), separating them from gangue, and subsequently recovering first-stage copper concentrate. Preliminary experiments revealed that the optimal consumption of collecting reagent (SIBX) is 80 g/t. These experiments demonstrated that primary flotation can be carried out by separating the primary copper concentrate at the first stage, since commercial copper concentrate can be obtained within the first minutes (the first three minutes of the flotation process) of the process. A concentrate with a copper content of approximately 30% and a recovery of 89% was obtained. It was found that with selective separation of concentrate in an open cycle during copper extraction in the first cycle, it is possible to obtain molybdenum concentrate with a molybdenum content of ≈ 0.9% and an extraction of 57.7%. In the future, it is planned to study the closed cycle of flotation enrichment of copper-molybdenum ore and metallurgical processing of the obtained concentrates.

https://doi.org/10.48081/BGQF2237

2026

Issue 2

This article quantitatively studied the processes of compressing multicomponent natural gas on a screw compressor filled with synthetic oil under conditions of unstable fluctuations in inlet pressure. As for the relevance of the study, the periodic and random input parameters of compressors operating in gas transmission systems are associated with the question of a more accurate forecast of the operating state during deviations. Quantitative modeling was carried out based on computational hydrodynamics (CFD): the actual geometry of the screw pair, leaks in the holes, turbulent effects and thermodynamic properties of the multicomponent mixture were taken into account using portable calculation meshes. Temporary change of inlet pressure is represented by samples of periodic and conditional random changes. For gas mixture typical for West Kazakhstan fields (CH, 78%, C ₂ H, 8%, C, 4%, C, H, 2%, N ₂, 5%, CO ₂ 3%), calculations in stationary, harmonic (f = 12 Hz, Δ p = ± 12%) It was found that the pulsation gain in the unstable suction mode reached the level of K _ p = 1.95-2.30, the volume productivity decreased by 8-10%, the polytropic efficiency decreased by 7-9% and the specific scope of work increased by 6.3-8.9%. The effect of gas components on energy characteristics was quantified, and it was found that the results can be used for engineering solutions to optimize the operating modes of compressor equipment.

https://doi.org/10.48081/BGQF2218

2026

Issue 2