This article presents the results of a theoretical study of the load distribution mechanism between the independent circuits of a steep-inclined conveyor. A dual-circuit apron conveyor is designed to support the transported load to prevent it from rolling. The traction-carrying circuit is a slat conveyor. The supporting circuit is a set of traction chains to which baffles are attached, ensuring the load is held on the supporting web. This design allows for a set of six chains (four on the lower circuit and two on the upper circuit) to act as the traction element, ensuring the maximum lifting height for a single conveyor, sufficient for most quarries. Load distribution between the independent circuits is accounted for by the load factors entered when determining the driving resistance. The dependences of the load factors of autonomous circuits on the weight distribution coefficients were established, as well as the dependences of the maximum values of the weight distribution coefficients on the autonomous conveyor circuits on the friction coefficient between the load and the carrier belt, the internal friction coefficient of the transported load, and the conveyor installation angle. These dependences can be used in calculations during the design of similar conveyor structures.

https://doi.org/10.48081/NiTK3.2026/588-605

2026

Issue 3

This article discusses modern technologies for thermal destruction of rocks, in particular, fire-jet methods used in the extraction of granite blocks. In the context of the active growth of the construction sector and the growing need for high-quality natural stone, the search for alternatives to traditional drilling and blasting methods, accompanied by a high level of waste and damage to the massif, is becoming especially relevant. As a promising approach, the use of thermal tools operating on the basis of fuel-air and oxygen-kerosene burners capable of providing directed rock destruction with high accuracy and minimal structural damage is considered. The article details the technical characteristics of various types of thermal tools, their mechanisms of action, the principles of formation and supply of combustible mixtures, as well as the features of the process of thermal destruction of rocks. Particular attention is paid to the design improvements of burners aimed at intensifying the combustion processes and increasing thermodynamic efficiency. Innovative approaches are described, including the use of ejection nozzles, fuel preheating, as well as the introduction of a detonation combustion mode to increase the power of the gas jet. The results of the studies confirm the high productivity of thermal cutting, which can significantly reduce the loss of conditioned raw materials and increase the profitability of production. The work is of practical value for mining specialists and can be used to modernize technologies at stone processing enterprises in Kazakhstan.

https://doi.org/10.48081/NiTK3.2026/30-53

2026

Issue 3

This study presents the development of a technology for producing chromium-manganese ligature under large-scale laboratory smelting conditions using a 100 kVA refining electric furnace. The charge materials included ferromanganese ore from the Kerege-Tas deposit and ferrosilicochrome (FeSiCr) dust generated during crushing. FeSiCr dust was used as a reducing agent due to its high silicon content. Seven smelting runs were carried out, resulting in the production of chromium-manganese ligature with the desired composition. The average chemical composition of the obtained alloy was: Fe – 35.63 %, Mn – 40.30 %, Cr – 20.94 %, Si – 4.54 %. The physico-chemical properties of the alloy were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis revealed the presence of an α-solid solution (Fe, Cr, Mn), as well as silicide phases FeSi and Cr₅Si₃. SEM images showed pronounced microstructural heterogeneity, porosity, and contaminant inclusions, which are associated with the uneven distribution of major elements within the alloy volume. The results confirm the feasibility of efficiently producing chromium-manganese ligature using FeSiCr dust and low-grade manganese ore, which is relevant for resource-saving metallurgical technologies in the context of Kazakhstan.

https://doi.org/10.48081/NiTK3.2026/369-380

2026

Issue 3

The study aims to evaluate the effect of external and internal treatments on the crystallization of complex-alloyed steel and the resulting casting properties. Experiments were performed using 40KhN3MF steel subjected to magnetic-field treatment, mechanical vibration, and melt modification. The results demonstrated that electromagnetic treatment primarily affected the hardness of the cast material, whereas mechanical vibration contributed to changes in strength and structural refinement. A full factorial experimental design was used to establish quantitative relationships between the investigated processing factors and the resulting response. The reproducibility of the experimental data was verified using Cochran's criterion, while the statistical significance of the regression coefficients was assessed using Student's t-test. The adequacy of the obtained regression model was evaluated using Fisher's criterion. Comparison of calculated and experimental values demonstrated satisfactory agreement within the investigated range of processing conditions. The results indicate that controlled external treatment during solidification can be used to modify the structural and mechanical characteristics of complex-alloyed steel castings and provide a basis for further optimization of casting conditions.

https://doi.org/10.48081/NiTK3.2026/360-368

2026

Issue 3

This study experimentally investigated changes in surface roughness under different combinations of cutting conditions and cutting tool parameters during CNC turning of cylindrical parts made of D16 aluminum alloy. The variable parameters included tool nose radius, cutting speed, feed rate, depth of cut, and tool offset. The experiment comprised nine combinations of the investigated technological parameters formed in accordance with the adopted experimental matrix. The surface roughness of the machined surfaces was evaluated using the Ra parameter by non-contact interferometric 3D profilometry. Within the investigated range of technological parameters, the surface roughness Ra values ranged from 2.287 to 3.564 µm. The lowest value, Ra = 2.287 µm, was obtained in experiment No. 7 at a tool nose radius of 0.8 mm, cutting speed of 100 m/min, feed rate of 0.25 mm/rev, depth of cut of 0.8 mm, and tool offset of +0.5 mm. The experimental data characterize the differences in surface roughness among the various combinations of the investigated technological parameters. The combination of parameters that provided the lowest Ra value among the nine investigated machining conditions may be considered rational within the scope of the experiment. The obtained results are of practical interest for selecting technological parameters for CNC turning of cylindrical parts made of D16 aluminum alloy.

https://doi.org/10.48081/NiTK3.2026/225-238

2026

Issue 3

The aim of this work was to deposit monolayer CrN and multilayer Cr/CrN coatings on E110 zirconium alloy and to evaluate the effect of the deposition gas flow and multilayer architecture on their structural state, mechanical and tribological properties, and resistance to high-temperature steam oxidation. The coatings were prepared by reactive magnetron sputtering of a chromium target. For the single CrN layer, Ar/N₂ gas flow ratios of 90/30, 85/35 and 80/40 sccm were tested. The multilayer Cr/CrN samples contained 2, 4 and 6 alternating layers. The samples were examined by SEM/EDS, XRD, GDOES, nanoindentation, AFM and ball-on-disc testing; steam oxidation was carried out at 1100 °C for 2 h. The CrN layer deposited at Ar/N₂ = 80/40 sccm showed the lowest roughness, Ra = 0.114±0.006 μm, and clear cubic CrN reflections in the XRD pattern. In the Cr/CrN series, the coating thickness increased with the number of layers and reached about 4.18 μm for the 6-layer sample. This coating showed H = 5.00±0.27 GPa, E = 110±4 GPa and a wear rate of 2.26×10⁻⁴ mm³·N⁻¹·m⁻¹. After steam exposure, Cr₂O₃ was detected on the coating surface, while weak CrN and Cr reflections remained in the 6-layer coating, indicating partial preservation of the internal layers. The practical significance of the study is the substantiation of multilayer Cr/CrN architecture as a promising protective barrier coating for next-generation zirconium fuel claddings under accident-tolerant fuel conditions.

https://doi.org/10.48081/NiTK3.2026/395-410

2026

Issue 3

The aim of this work is to validate a mathematical approach for describing the liquidus and solidus lines in the binary Mg–Si system based on the behavior patterns of the Bjerrum–Guggenheim osmotic coefficient. The structural and thermodynamic features of liquid magnesium–silicon alloys are analyzed within this framework, which allows deviations from ideal solution behavior to be quantitatively characterized. Numerical values of the osmotic coefficient are calculated using experimental phase diagram data, the Schröder–Le Chatelier equation, and tabulated thermodynamic properties of the components. Particular attention is paid to the crystallization of the congruent compound Mg2Si, where pronounced interatomic interactions in the melt lead to significant negative deviations of the osmotic coefficient from unity. For the Mg2Si–Mg and Mg2Si–Si subsystems, strong linear correlation relationships between temperature, composition, and osmotic coefficient are established, exhibiting high correlation coefficients. These relationships enable the derivation of analytical expressions for the crystallization lines and confirm the applicability of the proposed thermodynamic modeling approach for predicting phase equilibria in the Mg–Si system.

https://doi.org/10.48081/NiTK3.2026/460-471

2026

Issue 3

This paper presents the results of a comprehensive investigation of the structural-phase state, tribological, and mechanical properties of nanocomposite multilayer (TiAlSiY)N/CrN coatings deposited by the vacuum arc deposition method. The aim of the study was to establish the relationship between the technological deposition parameters, the features of coating structure formation, and their operational properties under thermomechanical loading conditions. The coatings were deposited onto stainless steel substrates and characterized using nanoindentation, scratch testing, acoustic emission analysis, and energy-dispersive X-ray spectroscopy. In addition, wear resistance tests were carried out under contact loading conditions simulating the operation of metallic materials under elevated temperatures and mechanical stresses. The coefficient of friction, critical failure loads, as well as the mechanisms of wear and degradation of surface layers were determined. It was found that the coatings obtained under the second deposition regime exhibited the best performance characteristics, including minimal wear intensity, a stable coefficient of friction (µ≈0.35–0.45), and enhanced adhesion strength. The initiation of crack formation in the coating was observed at a load of LC₁≈17 N, whereas coating failure associated with the loss of adhesion to the metallic substrate occurred only at a significantly higher load of LC₅≈150 N. The acoustic emission intensity remained low and stable up to LC₄≈85 N, indicating high structural stability of the coating and the absence of premature local failure. It was demonstrated that the enhanced wear resistance of the (TiAlSiY)N/CrN coatings is associated with their multilayer nanocomposite architecture, which promotes effective dissipation of mechanical energy, suppresses crack propagation, and increases resistance to degradation of the surface layers. The obtained results are of practical interest for coating metallurgy and surface modification technologies of metallic materials intended for operation under severe thermomechanical loading conditions.

https://doi.org/10.48081/NiTK3.2026/287-303

2026

Issue 3

This study investigates the effect of plasma spraying energy input on the microstructure and properties of APS-sprayed ZrO₂–Y₂O₃ (YSZ) coatings deposited on 12Cr18Ni10Ti stainless steel substrates. The coatings were produced under different spraying conditions by varying arc current, arc voltage, plasma gas flow, powder feed rate, and stand-off distance. A specific energy input to powder was used as a comparative parameter to characterize the thermal loading of particles during spraying. The microstructure of the coatings was examined by scanning electron microscopy, and porosity was evaluated from cross-sectional images using image analysis. Microhardness was measured under HV0.1 and HV0.3 loads, surface roughness was assessed using the Ra, Rz, and Rt parameters, and corrosion behavior was studied by potentiodynamic polarization in a 3.5 wt.% NaCl solution. The results show that spraying conditions significantly affect coating density, porosity, microhardness, roughness, and electrochemical response. The lowest porosity was obtained for the coating produced under intermediate spraying conditions and amounted to 3.2 ± 0.5%, while coatings formed under lower and higher energy input exhibited porosity values of 4.5 ± 0.3% and 6.7 ± 1.6%, respectively. A decrease in microhardness with increasing porosity was observed, particularly at the HV0.3 load, due to the influence of interlamellar defects on the effective load-bearing area. The corrosion behavior of the coatings was found to depend not only on total porosity but also on defect morphology and pore connectivity. Overall, the results confirm that plasma spraying energy input strongly influences the structure and performance of APS-sprayed YSZ coatings and can be used to optimize spraying conditions.

https://doi.org/10.48081/NiTK3.2026/119-131

2026

Issue 3

Biogas represents a highly viable renewable energy source, currently adaptable as a primary motor fuel for spark-ignition internal combustion engines. This study investigates the biogas matrix generated through the anaerobic digestion of cattle manure. The resulting gaseous mixture underwent upgrading processes to match natural gas quality standards, followed by subsequent compression. The implementation of bioenergy units in rural sectors, along with the processing of methane fuel for agricultural machinery and transport, introduces transformative properties into farming infrastructures: ensuring total energy self-sufficiency, addressing organic waste management challenges, and expanding production outputs. The paper provides comparative evaluations regarding the extensive utilization of bioenergy in transport powertrains. A comprehensive mathematical modeling methodology is proposed to predict combustion pathways within a spark-ignition gas engine converted from a turbocharged diesel prototype. The heat release characteristics, alongside the indicated and brake performance parameters of the retrofitted unit, were quantified using the modified Wiebe function. The governing equations defining the combustion character and overall duration are strictly derived from preliminary empirical datasets. Through the mathematical processing of experimental variables, a novel empirical correlation was established to characterize the distinct impact of carbon dioxide 〖CO〗_2 content on the fuel burn rate. The emission profiles and exhaust toxicity indexes were evaluated relying upon Zvonov’s analytical framework. Finally, the reliability and predictive accuracy of the formulated simulation model were validated and verified against the obtained experimental metrics.

https://doi.org/10.48081/NiTK3.2026/516-534

2026

Issue 3