Vol 29, No 2 (2025)

Objective – development of a comprehensive model that takes into account the interrelationship between the structure of a gear wheel, material properties and technological processing parameters. This model should predict the operational characteristics of the wheel, considering the impact of both internal and external factors. Mechanical testing was conducted using electromechanical tensile testing equipment from Tinius Olsen, model H100KU, to determine the mechanical properties of the metal. Samples in compliance with GOST 1497-84 were used for monitoring material properties (tensile strength, yield strength, etc.) at loads above 100 N/mm2. The mechanical properties of the metal were monitored after each processing operation. The mechanical properties of the steels 16Kh3NVFMB-Sh, 20Kh3MVF-Sh, 18Kh2N4MA and 12Kh2N4A-Sh were investigated for different blanks and types of treatment (pressure forming, mechanical and abrasive, thermochemical and heat treatment). Analysis of the mechanical properties of the metal revealed significant differences in hardness, strength and ductility between samples obtained by different methods. It was shown that these differences are due to the microstructure of the material (grain size, presence of inclusions, degree of deformation) formed during processing. The analysis was based on parameters including the coefficient of technological inheritance and structural inheritance. It was found that the inheritance of the mechanical properties of the material through pressure working followed by heat treatment shows a positive trend relative to rolled material with similar heat treatment. This method results in an increase in tensile strength of up to 6.2% and in yield strength of up to 5.3%. Furthermore, it was shown that the increase in the quantitative indicator of structural inheritance after thermochemical treatment, relative to grinding of the hardened layer, is at least 49% for tensile strength and at least 68% for yield strength. The developed multidimensional model of gear interaction takes into account a wide range of factors that influence its operation, including material properties, temperature fields in the contact zone of the tooth, dynamic loads and the effect of lubricant.

Objective – improvement of the precision of finish reaming of hollow cylinder type components by using preventive compensation for cutting tool wear. The study focuses on hollow cylinder type components, exemplified by the liners of drilling pump cylinders, where the finish machining of the central bore is studied. The machining is performed on a numerically controlled lathe. The proposed approach involves dynamic monitoring of the cutting-edge condition during the production of a test batch. The cutting blade is described as a set of points that subsequently approximate the contour of the cutting edge. Since the wear pattern of each individual insert is random, the study uses an artificial intelligence approach to solve the prediction problem. A neuro-fuzzy model was developed to describe the cutting edge during wear. The model includes a knowledge base that is updated based on the monitoring results of the cutting edge shape. The model also includes a logical block containing a set of conditions that enable the simulation results to be produced with the required accuracy. Testing of the developed model shows that the error in describing the cutting edge contours does not exceed 8%. On the basis of the calculated descriptions of the blade contour, corrections to the cutting tool trajectories are calculated, which allow compensation for the wear of the cutting plate. Research into the effectiveness of the solutions obtained has shown that it is possible to increase tool efficiency (in terms of tool life) by 35–45%. In addition, the developed neuro-fuzzy model can be integrated into an expert system that helps to reduce the risk of sudden cutting tool failure. This is particularly important in the manufacture of hydraulic machine components.

Objective – determination of the causes of structural failure using computer modelling based on stress-strain state analysis. The initial data for the computer modelling included photographic material from the site of the accident, design documentation and technical specifications of the vehicle (loaded with timber) and the hydraulic shears. The software packages used were APM WinMachine, NX and Autodesk Inventor. The Finite Element Method in displacements was selected as the primary research method. Various crack initiation scenarios were considered, computer models were developed and an engineering analysis of the vehicle frame structure was performed. Computer modelling also identified the most likely cause of failure of the upper part of the hydraulic shear – exceeding the critical stress level (345 MPa, the yield strength of the 09G2S steel) for the material. The studied structures were characterised by complex geometries and a variety of loads acting on them. Welded seams were considered in their modelling. Geometric models of the structures, including the welded seams, were created in the software packages using the finite element method. On this basis finite element models of the structures were developed and analysed. As a result of the stress state calculations for the hydraulic shear, the maximum stress value (391 MPa), which is significantly higher than the yield strength, and the stress localisation for different loading cases were determined. Analysis of the results of the strength and stiffness calculations for all the models developed were used to test the hypotheses considered in the software packages. This made allowed identification of the most probable causes of failure. The developed methodology, along with the computer models and the results obtained, can be applied in the engineering and technical analysis of a variety of technical objects.

Objective – a review of modern desulfurization technologies for high-sulphur petroleum coke. This study will further asses their effectiveness, economic feasibility and impact on the properties of carbon materials used in the production of cold-pressed masses, aluminium electrolyser anodes and graphitized electrodes. Based on the analysis of literature sources, methods for the treatment of both coking feedstock and finished coke are considered: hydrodesulphurisation, oxidative and alkaline treatment, thermal calcination, biological leaching and hybrid technologies. Feedstock characteristics and process parameters (temperature, pressure, particle size, catalysts) were studied as well as their effect on the degree of sulphur removal and the associated structural changes in the carbon matrix. Hydrodesulphurisation of coking feedstock reduces sulphur content to 0.2–1.5%, but is costly, has low coke yield and loses effectiveness in the presence of metals in the ash. Alkaline treatment removes up to 90% of the sulphur, but increases ash content and porosity. Thermal calcination up to 1500°C removes 85% of the sulphur but leads to degradation of the carbon structure. Biological processes can be up to 92% efficient, but are time consuming. Hybrid technologies, such as vacuum heat treatment with alkaline activation, show the greatest potential for desulphurisation, achieving maximum sulphur removal efficiencies (up to 98.5%) while maintaining mechanical strength. This shows that the choice of desulphurisation method depends on the initial composition of the coke and the requirements of the final product. For example, desulphurisation of coking feedstock is economically justified for low-sulphur oils, whereas treatment of finished coke is suitable for high-sulphur materials, but reduces their density and strength. Hybrid processes that combine cleaning efficiency with minimal impact on coke structure are promising. The literature review showed that the development of low-cost catalysts, reduction of energy consumption and utilisation of sulphur containing gases are necessary for the scale-up of effective technologies.