AP13067723 “Development of theoretical foundations for the implementation of innovative combined deformation processes of non-ferrous metals and alloys in order to obtain a fine-grained structure”

Combined pressure treatment processes are one of the most promising methods of deformation. They include two or more discrete deformation processes. This combination gives advantages over individual methods. For example, it is possible to ensure the continuity of the process, the expansion of the assortment is realized due to the deformation of long blanks. Therefore, the development of new combined deformation technologies that allow obtaining high-quality workpieces and their theoretical justification is an urgent task.

The main idea of the project is to develop the theoretical foundations of new combined technologies for deforming non-ferrous metals and alloys, allowing for intensive plastic deformations in the material, which will contribute to the development and introduction into production of new innovative technologies for producing long-length metal products with an increased level of mechanical properties.

1) Panin Evgeniy Alexandrovich – PhD, Associate Professor, Associate Professor of the Department of Metal Forming, project manager.

Scopus ID: 55903153300  

ResearcherID: B-7581-2015 

https://orcid.org/0000-0001-6830-0630

2) Volokitin Andrey Valeryevich – PhD, Associate professor of Department of Metal Forming, project executor.

Scopus ID: 56524247500  

ResearcherID: U-8580-2018

 https://orcid.org/0000-0002-0886-3578

3) Akhmetova Gulzhainat Yesenzholovna – PhD, Associate Professor, Associate Professor of the Department of Metallurgy and Materials Science, project executor.

Scopus ID: 57195377183

4) Volokitina Irina Evgenyevna – PhD, Associate Professor, Professor of the Department of Metallurgy and Materials Science, project executor.

Scopus ID: 55902810800  

ResearcherID: G-4526-2018

https://orcid.org/0000-0002-2190-5672

5) Tolkushkin Andrey Olegovich – Master’s degree, project executor.

Scopus ID: 57000494500

6) Esbolat Aibol Batyrkhanovich – Master’s degree, lecturer at the Department of Metal Forming, project executor.

Scopus ID: 57931507900 

ResearcherID: JMQ-0969-2023

Based on the analysis of scientific, technical and patent literature, 3 new combined processes of implementation in the process of deformation of intense plastic deformation will be developed, allowing to obtain long-length products made of non-ferrous metals and alloys with an ultra-fine-grained structure; analytical dependences of deformation forces on the geometric and technological parameters of the ECAP-Linex process will be determined, allowing to determine rational parameters of implementation this process; computer models of the new ECAP-Linex combined process will be built and the influence of technological and geometric parameters of the process on the stress-strain state, energy-force parameters and the evolution of the microstructure of the workpiece material will be established.

Analytical dependences of deformation forces, back pressure, and speed characteristics on the geometric and technological parameters of the rolling-ECAP process with combined rolls (1 pair of horizontal rolls, the 2nd pair of vertical rolls) will be determined; computer models of the rolling-ECAP process with combined rolls will be built and optimal parameters ensuring the best stress-deformed state and power parameters; Using the Kolmogorov (JMAK) and cellular Automata methods, the influence of technological and geometric parameters of the rolling-ECAP process with combined rolls on changing the shape and grain size of the initial structure of the deformable material will be established.

Modeling of the melt crystallization process into a solid billet for subsequent deformation will be carried out; optimal parameters of the casting-rolling-ECAP process will be determined, providing the best stress-strain state and energy-force parameters; dependences of technological and geometric parameters of the combined casting-rolling-ECAP process on changes in the shape and size of grains of the initial structure will be obtained deformable material; recommendations will be developed for the introduction of the developed technologies into production.

Based on the results of scientific research, 2 (two) articles will be published in peer-reviewed scientific publications in the scientific field of the project, indexed in the Science Citation Index Expanded of the Web of Science database or having a CiteScore percentile in the Scopus database of at least 35 (thirty-five). In addition, one (1) article will be published in a peer-reviewed foreign or domestic publication recommended by SHEQAC. The results of the research will be reported at international European conferences in Bulgaria, the Czech Republic, Poland or other international conferences abroad, as well as at international conferences in Russia, Belarus and Kazakhstan.

1 Based on the analysis of scientific, technical and patent literature, 3 new combined processes have been developed for the implementation of intense plastic deformation in the deformation process, which make it possible to obtain long-length products from non-ferrous metals and alloys with an ultra-fine-grained structure

During the implementation of this section, it was revealed that it is difficult to solve the problem of obtaining ultrafine-grained materials using traditional methods of metal pressure treatment. A promising direction in the development of metal forming processes is the development of shear deformations, which change the force characteristics of the process, since shear hardening occurs less than during strain by stretching or compression. Also, along with the implementation of shear deformations, a promising direction can be considered the development and research of pressure treatment methods based on the principle of intensification of alternating deformation, which will allow to work out the structure in the axial zone of the metal and improve the quality of finished products. When analyzing the metal forming methods, it was revealed that the implementation of intense plastic deformations allows to significantly improve the quality of the processed metal. Metal forming methods, which allow to obtain blanks with an ultrafine-grained structure, are characterized by grinding the structure of the workpiece during deformation, as a result of which the mechanical and operational properties of the processed metal are increased. But, having analyzed the main methods of obtaining UFG materials, it was concluded that none of these methods, due to high energy consumption, is ready for economically justified widespread industrial use. This problem can be solved by ensuring the continuity of the process and the possibility of deformation of long blanks. The development of combined metal forming processes, which are a combination of two or more conventional deformation processes, is the newest and most promising direction for the development and improvement of metal forming methods. The main feature of combined metal forming processes is that often, when they are implemented, the disadvantages of conventional metal forming processes that are included in the combined process are reduced or completely eliminated. The considered combined deformation processes have significant technological advantages over classical discrete SPD processes. At the same time, they also have certain disadvantages. The proposed three new concepts of combined processes of intensive plastic deformation are aimed at further improving the deformation performance. And the presence in all three proposed variants of the ECAP scheme will allow for deformation without significantly changing the initial dimensions of the workpiece.

2 The analytical dependences of the deformation forces on the geometric and technological parameters of the ECAP-Linex process have been determined, which make it possible to determine the rational parameters of the implementation of this process. 

In this section, theoretical studies of the combined ECAP-Linex process have been carried out. To analyze the resulting deformation forces, the stages of pressing in a matrix and compression by a belt conveyor are considered separately. The formulas obtained were verified during the trial calculation. A comparative analysis with the previously known rolling-ECAP process showed that the new ECAP-Linex process allows for a stable deformation process with lower forces and a smaller channel junction angle in the matrix, which will lead to an increase in the level of metal processing at the pressing stage.

3 Computer models of the new ECAP-Linex combined process were constructed and the influence of technological and geometric parameters of the process on the stress-strain state, energy-force parameters and the evolution of the microstructure of the workpiece material was established. 

In this section, the finite element modeling of the ECAP-Linex process is carried out. For a correct simulation of the process, a method is presented with sequential input into the calculation of conveyor links. To analyze the effectiveness of metalworking, the main parameters of the SSS are considered: equivalent deformation, equivalent stress and average hydrostatic pressure, as well as the evolution of the microstructure and the deformation force on the main elements of the combined process: pulley, die and conveyor link. The variational modeling made it possible to evaluate the above-mentioned parameters when changing the main technological and geometric parameters of the process. As an optimization parameter for pressure treatment, either the level of metal processing is usually considered, on which the intensity of grain grinding directly depends, or the deformation force. From this point of view, a matrix with an angle of 125° is the most optimal in terms of grain grinding, and at the same time not recommended in terms of effort. At the same time, the matrix with an angle of 155° has opposite recommendations. Therefore, in this combined process, it can be recommended to use a matrix with an angle of 140° as a golden mean. An increase in the heating temperature of the workpiece below the starting point of recrystallization has a beneficial effect on reducing energy-strength parameters with an almost constant level of metal processing. The change in velocity characteristics has no pronounced positive or negative properties, except for a decrease in the level of grain elongation due to a decrease in tensile stresses in the inclined channel of the matrix at a reduced deformation rate. Therefore, we can recommend any of the considered high-speed options. The friction coefficients in the matrix and the conveyor must have the limit values set in the basic model (0.7 for the conveyor and 0.05 for the matrix), their change leads to a violation of the deformation stability. Similarly, it is not recommended to increase the base lengths of the matrix channels: 30 mm for the first channel, 20 mm for the second channel, 15 mm for the third channel. An increase in the second channel leads to jamming of the workpiece, and an increase in the first and third channels would be an irrational solution, since in this case there are no significant changes in SSS, effort or microstructure.

4 The analytical dependences of the deformation forces, back pressure, and speed characteristics on the geometric and technological parameters of the rolling-ECAP process with combined rolls (1 pair of horizontal rolls, 2 pair of vertical rolls) are determined

In this section, an analytical study of the power and kinematic parameters of the combined rolling-ECAP process with combined rolls was carried out. Based on previous studies of the combined process with two pairs of horizontal rolls, theoretical dependencies were obtained to determine the back-up forces in the matrix. A kinematic calculation of the rolling-ECAP process was carried out using smooth and calibrated rolls to determine the parameters ensuring the continuity of this process. It was found that in addition to the speed of the metal at the exit from the matrix, the key factor is the diameter of the second pair of rolls, by varying the value of which it is possible to achieve the optimal speed of the rolls for this combined process.

5 Computer models of the rolling-ECAP process with combined rolls were constructed and optimal parameters were determined to ensure the best stress-strain state and energy-strength parameters.

In this section, finite element modeling of the rolling-ECAP process with combined rolls was carried out. To analyze the effectiveness of metalworking, the main parameters of the SSS were considered: equivalent deformation, equivalent stress, average hydrostatic pressure, as well as the deformation force on the main elements of the combined process: two pairs of rolling rolls and an equal-channel step matrix. For variational modeling, models were built with changes in such technological parameters as the heating temperature of the workpiece and the deformation rate.

Either the level of metal working, which depends on the equivalent deformation, or the deformation force is usually considered as a key parameter in pressure treatment. From this point of view, the most optimal option is the basic model, in which the workpiece was heated to 100°C. The deformation was carried out at a circumferential speed of the first pair of rolls of 60 rpm. Options with a single temperature reduction to 20°C, or a deformation rate of up to 35 rpm also give acceptable results to all considered indicators. However, reducing the deformation rate to 10 rpm makes it impossible to carry out a stable process at any temperature.

6 Using Kolmogorov (JMAK) and cellular Automata methods, the influence of technological and geometric parameters of the rolling-ECAP process with combined rolls on the change in the shape and grain size of the initial structure of the deformable material was established.

In this section, finite element modeling of the evolution of the microstructure of the combined rolling-ECAP process with combined rolls using JMAK and Cellular Automata methods was carried out. The analysis of the microstructure evolution data allows us to confirm the conclusion made earlier in the SSS analysis – the most optimal option is the basic model in which the workpiece was heated to 100 °The deformation was carried out at a circumferential speed of the first pair of rolls of 60 rpm. At the same time, variants with a single temperature reduction to 20 ° C or a deformation rate of up to 35 rpm also give good results in grain grinding, only slightly inferior to the basic model in the intensity of grinding. At the same time, using the Cellular Automata method gives an advantage over the JMAK method and obtaining data not only on changes in grain size, but also its shape.

7. Modeling of the process of crystallization of the melt into a solid billet for subsequent deformation is carried out. Rational technological parameters of the process have been determined, which make it possible to obtain a billet with a minimum proportion of liquid melt in the core, which is immediately suitable for deformation at the outlet.

8. The optimal parameters of the casting-rolling-ECAP process have been determined, providing the best stress-strain state and energy-strength parameters by finite element modeling of the rolling-ECAP process for the workpiece obtained at the previous stage of research.

1. Panin E.A., Naizabekov A.B., Volokitin A.V., Akhmetova G.E., Volokitina I.E., Tolkushkin A.O. New concepts of severe plastic deformation combined processes. VII International scientific conference “Industry 4.0”. 22–25 June, 2022, Varna, Bulgaria, Vol. 1, pp. 101-103.

2. E. Panin, I. Volokitina, A. Volokitin, A. Naizabekov, G. Akhmetova, S. Lezhnev, A. Tolkushkin, A. Esbolat, R. Yordanova, Finite Element Modeling of ECAP-Linex Combined Process of Severe Plastic Deformation, Modelling and Simulation in Engineering, 2023, – 1573884. https://doi.org/10.1155/2023/1573884 (Scopus, 62th percentile);

3. Панин Е.А., Ахметова Г.Е., Волокитина И.Е. Теоретическое исследование силовых параметров совмещенного процесса «РКУП-Лайнекс» // Глобальная энергия. 2023. Т. 29, № 1. С. 157–169 (indexed in the Russian Science Citation Index (RSCI) hosted on the Web of Science platform – equated to КОКСОН RK)- https://doi.org/10.18721/JEST.29109 ;

4. Е.А. Панин, А.В. Волокитин. Конечно-элементное моделирование эволюции микроструктуры при деформировании методом «РКУП-Лайнекс». МНТК молодых ученых «Инновационные материалы и технологии – 2023». г. Минск, Республика Беларусь. 21-23 марта 2023 г. – с. 237-241;

5. Е.А. Панин, А.В. Волокитин, А.Б. Найзабеков, С.Н. Лежнев, И.Е. Волокитина. Исследование совмещенных процессов интенсивной пластической деформации с помощью моделирования методом конечных элементов. Машиностроение: сетевой электронный научный журнал. 2023. Том 10, №2. – c. 11-15.

6. Панин Е.А., Есболат А.Б., Уткин Н.Е., Волокитин А.В., Ахметова Г.Е. Новые схемы совмещенных процессов деформирования для эффективной проработки металла. Третья Международная школа-конференция молодых ученых «Кайбышевские чтения», 16-21 октября, Уфа, Россия, С. 104-105.