Calibrated rolls are one of the important elements of section-rolling equipment, providing the formation of the required geometry and properties of metal products. At the same time, at rolling of traditional in calibrated rolls in finished rolled products there are remnants of cast structure and inhomogeneity of mechanical properties of metal along the cross-section. The mentioned disadvantages can be eliminated by realization of severe plastic deformation (SPD) in the volume of metal. However, low manufacturability of the majority of SPD technologies restrains their use in industry. Therefore, the development and research of a new method of SPD realization in conditions of technological process continuity, in particular during rolling in continuous mills, is an actual scientific and technical problem. In this paper a new scheme of rolling rolls calibrations is considered, providing the realization of intensive shear deformation. The analysis of the existing schemes of rolling in gauges is carried out and an effective system of gauges for the realization of transverse shear is proposed. The efficiency of the new rolling scheme is evaluated on the basis of stress-strain state analysis based on the results of the process modeling by the finite element method (FEM). It is established that strip rolling in gauges realizing shear deformations provides non-monotonic character of plastic flow and more favorable indices of stress-strain state of metal in comparison with rolling in traditional gauges.

https://doi.org/10.48081/ISPR9282

2023

Issue 4

Simulation modeling of hollow billet casting processes for the production of seamless oil grade pipes was performed. The aim of the work was to study the influence of geometric shape on the quality and properties of a continuously cast pipe billet. Modeling parameters, initial and boundary conditions were selected taking into account the conditions of the current production. The object of the study was a pipe billet with a diameter of 210 mm. When modeling the process of casting and solidification of billets, low-alloy structural chromium-molybdenum steel was used. For the simulation processes, three-dimensional models of billets were created, as well as models of shapes. Several factors were taken into account when modeling continuous casting and crystallization of a hollow billet: casting speed, chemical composition of the alloy being poured; casting temperature; geometric dimensions of the billet section. Modeling of hollow billet casting in the “LVM Flow” software package predicted the non-shrinking structure formation a decrease in microporosity (more than 0.85 according to the Niyama criterion) of the billet. As a result of simulation modeling, the improvement of the structure is theoretically confirmed when using a hollow steel billet as a starting point for the production of seamless hot-rolled pipes. There were no signs of shrinkage and microporosity on the hollow billet exceeding the permissible value according to the Niyama criterion.

https://doi.org/10.48081/CBPX3907

2023

Issue 4

The article shows how the feed during waterjet cutting affects the roughness of the cutting surface. Cutting is performed by a mixture of water and abrasive emitted from the nozzle at high speed and under high pressure. Under the action of the cutting jet, erosive destruction of the material occurs, abrasive particles remove a layer of micro-chips, and water evacuates them from the cutting zone. Waterjet cutting can be used to process almost any materials. The cutting process is "cold", there is no thermal effect on the metal. Cutting of complex geometry is possible. The analysis showed the absence of dependencies for predicting the roughness of the cutting surface on the main processing parameters (jet pressure, grain size, abrasive consumption, physical and mechanical parameters of the material, etc.). The production technologist faces the difficulty of determining not only the roughness of the cut surface, but also the size of the smooth and wavy cut zone. The lack of adequate theoretical models for the formation of the roughness profile does not allow optimization of the cutting process, taking into account the requirements of a given roughness. The possibility of optimizing the cutting process according to a given roughness value makes it possible for practical application in the development of technological processes. The dependences of determining the surface roughness for a characteristic section of the cut surface are obtained. Recommendations are given to reduce the number of defects that occur during waterjet cutting. Experimental studies confirming the adequacy of the obtained theoretical models have been carried out. Discussions and conclusions. As a result of the research, it was found that the roughness of the treated surface worsens with increasing feed. In this case, the deterioration is unevenly distributed along the section of the cut. To reduce the width of the wavy cut, it is necessary to reduce the feed value. Keywords: waterjet cutting, surface quality, cutting modes, feed, nozzle, cutting head, abrasive consumption, erosive destruction of metal.

https://doi.org/10.48081/AJOG5498

2023

Issue 4

One of the main problems that needs to be addressed is the use of renewable energy by justifying the design of the blades to reduce fuel consumption and power by creating mechanical power using two or three blades in an ordinary wind turbine. Each blade length was 0.22 meters, and the pitch angle of the blade was 2 degrees to reach the maximum power from the wind, as shown in the simulation, depending on the beta limit. Solidwork was used to design the turbine and to find its moment of inertia and initial parameters. Matlab is used to simulate the system equations to find the turbine power coefficient depending on the ideal pitch angle (Beta) and the tip speed ratio (Lambda) and also to find the required mechanical power to drive different small mechanical devices with an assumed power of 1400 Watt. As a result, the wind turbine's optimal power required at wind speed is near 31.5 m/s (113.4 km/h), and for less wind speed, the device could work with less efficiency. Otherwise, high speeds produce the best efficiency.

https://doi.org/10.48081/DCZW7901

2023

Issue 4

Phase change materials are latent heat storage materials. As the source temperature rises, the chemical bonds within the PCM break up as the material changes phase. Upon storing heat in the storage material, the material begins to melt when the phase change temperature is reached. The temperature then stays constant until the melting process is finished. The heat stored during the phase change process of the material is called latent heat. Ideally, automotive engine cooling is undesirable from the thermodynamic point of view. If the heat transfer rates from the gas to metal could be reduced, then more power could be produced at a particular fuel flow rate, i.e. the thermal efficiency of the engine would increase. Also the heat removed out via radiator could be reduced and hence smaller radiator size. That is why powertrain thermal management is extremely necessary for good engine reliability and durability with a compromise of the thermal efficiency. One of the most technically and commercially available options for this is the use of latent heat thermal energy storage system. Despite the fact that there are numerous works and reviews covering this topic, the author hopes to draw attention to some aspects of the choice of material and mathematical model for such systems.

https://doi.org/10.48081/NOWD5861

2023

Issue 4

This article presents the results of petrographic and thermographic studies of high-base manganese ores of the «Ushkatyn III» deposit, necessary for metallurgical production. The research results have shown that the manganese ore at this deposit has a low phosphorus content in harmful impurities and a high content of calcium oxide. This deposit can be considered as the optimal raw material for melting manganese alloys.. In this regard, radiophasic phase and mineral-petrographic, thermographic analysis of concentrates was carried out to obtain the quantitative mineralogical and chemical composition of the primary manganese ores of the deposit. A selective sample of the manganese ore of the deposit was carried out on an X-ray diffractometer DRON - 2.0. In connection with the radiophasic analysis, the following minerals were found in the ore: brownite (Mn2O3∙MnSiO3), bixbyite (Mn,Fe)2O3, calcite (CaCO3), hematite (ɑ-Fe2O3). Mineralogical and petrographic analysis was carried out using a portable metallurgical microscope model «NYMCS-605». Microscopic studies have established that the samples of primary manganese ores represent gausmanite ore (Mn3O4) of a banded structure due to the alternation of shiny dark interlayers of dense fine-crystalline gausmanite and lighter non-metallic bands consisting of carbonate with a small amount of chalcedony (SiO2) and in places crystalline tephroite (Mn2SiO4). In the thermographic analysis of manganese ore F. Paulik, J. Paulik, L. Erdei Derivatograph Q = 1000, the study was carried out in the temperature range of 25-1000 ° C with a heating step of 10 ° C/min. According to thermographic calculations, in the temperature ranges of 930-950C, an insignificant endothermic effect of the decay of the previously formed β- kurnakite with the formation of β-gausmanite in the sample was observed. According to the results of petrographic, thermographic analysis of the microstructure of high-base manganese ores of the «Ushkatyn III» deposit, the possibility of its application on manganese ferroalloys has been proved.

https://doi.org/10.48081/WLJX8085

2023

Issue 4

This article presents the results of calculations of the thermodynamic parameters of binary Fe-Cr and Fe-Ti systems based on their state diagrams using the Bjerrum-Guggenheim osmotic coefficient, for the region of iron crystallization from the iron activity of an ideal α-γ solution for the above systems. When calculating the lines of phase equilibrium in the Fe-Cr and Fe-Ti systems, it was established that the Bjerrum-Guggenheim coefficient can serve as an assessment parameter characterizing the role of exchange forces between atoms, and by its dimension (Фi><1) one can qualitatively judge the nature of the intermolecular interactions in the system. The results of this work made it possible to correctly solve the direct Gibbs problem, namely, to obtain the analytical dependence of phase compositions on temperature at phase equilibria based on the laws of phase formation. It is shown that with the help of the Bjerrumm-Guggenheim osmotic coefficient (Fi), the real equilibrium in the system under study can be determined in detail and their correct analytical expression can be obtained. When calculating phase equilibrium lines in systems with different types of interaction between components, it was established that the Bjerrum-Guggenheim coefficient can serve as an assessment parameter characterizing the role of exchange forces between atoms.

https://doi.org/10.48081/BQPI6828

2023

Issue 4

Die mechanische Bearbeitung von Metallen in Form eines Zylinders wird von wesentlichen thermodynamischen Prozessen begleitet. Die Wärmequelle beim Schneiden von Metallen ist die Arbeit, die für Verformungen in der Schnittschicht und in den Schichten neben der bearbeiteten Oberfläche und der Schnittfläche und für die Überwindung der Reibung an der Vorder- und Rückseite des Schneiders aufgewendet wird. Die Prozessmodellierung kann einen großen Beitrag leisten und den Innovationsprozess beschleunigen und die Entwicklungszeit der Zyklen verkürzen, indem sie notwendige Experimente unterstützt, da sie im Vergleich zu experimentellen Studien weniger kostenintensiv, weniger gefährlich und weniger Vorbereitungszeit benötigen. Dabei werden die simulierten Schneidprozesse durch viele verschiedene Phänomene reguliert, beispielsweise die Mechanismen der Streu- und Trennenergie von Materialien, die gleichzeitig die Qualität der betreffenden Bearbeitungssysteme beeinflussen. SPH ist wirklich keine Mesh-Methode, da es kein Hintergrundraster benötigt. In SPH wird der Rechenbereich mit Lagrange-Teilchen abgespeichert, die variable Felder tragen und sich mit dem Material bewegen. Die zelllose und lagrangeartige Natur von SPH macht es ideal für die mathematische Modellierung der Metallverarbeitung. Die Arbeiten zeigen, dass Scherbänder und Spanbildung natürlich ohne spezielle Behandlung, wie z. B. Knoten-Anreicherung oder Neuplanung, eingefangen werden. Die SPH-basierte Simulation in LS-DYNA wird durchgeführt, um Schnittkräfte, plastische Verformungen und die Schnittebene mit großer Präzision vorherzusagen.

https://doi.org/10.48081/APMX5155

2023

Issue 4

The article analyzes the main technological factors affecting the quality of parts, specifically the quality of the treated surface or the roughness of the surface of the part. Turning (boring) was considered as an example, and a number of measures aimed at improving the quality of the surface at the design stage were also proposed. A simulation stochastic model of surface roughness shaping during surface turning was proposed. Based on this model, an algorithm and a computer program were developed to calculate the roughness at the design stage. The initial data for modeling are the main angle in the plan φ, the auxiliary angle in the plan φ1, the radius at the tip of the cutter r and the feed S, as factors that most strongly affect the roughness during boring. An experiment was carried out, where not only average values were obtained, but also histograms of the distribution of roughness parameters, the adequacy of this model was proved. When calculating the roughness, additional factors were taken into account, for example, the condition of the machine, which made it possible to correct the simulation stochastic model and introduce vibration components associated with the forces acting during cutting and elastic squeezes of the cutter during boring process.

https://doi.org/10.48081/WUTY7402

2023

Issue 4

In this work, isothermal and polythermal calculations of the system Ti-2.5Al-5Mo-5V with the addition of different wt.% Zr were carried out with the program Thermo-Calc Perpetual SUNLL 2023a using the TCS Ti-and TiAl Alloys Datebase, Perpetual DSUNLL 5. The phase composition change rates of the alloy of the Ti-Al-Mo-V-Zr system alloy as a function of cooling condition and composition were determined by calculation. Introduction of zirconium into the titanium alloy of the Ti-2,5Al-5Mo-5V system in the amount of 1 % leads to a significant change in the phase composition. It is established that titanium alloys alloyed with a small amount of zirconium are two-phase, and in this connection it is irrational to increase the content of zirconium above 1 %. Polythermal calculations determined the optimal composition of titanium alloy, wt. %: 2,5 Al, 5 Mo, 5 V, 1Zr, the rest titanium. It was found that in the temperature range of 660-700 °C there is an equal distribution of the amount of α and β phases. In order to fix the necessary double α + β region it is necessary to carry out additional heat treatment of the alloy at 660-700 °С, and the process of further rolling of the alloy into sheets makes it possible to obtain an ultrafine-grained structure, due to which increased strength, plastic and fatigue properties are achieved.

https://doi.org/10.48081/CTWE8923

2023

Issue 4