АР19674502 «Development and research of a technological method for implementing intense shear strains during rolling in calibrated rolls»

Longitudinal rolling in calibers is one of the main technologies for obtaining long metal products. At the same time, during traditional rolling in calibers in the finished rolled products the remains of the cast structure and heterogeneity of the mechanical properties of the metal across the cross-section are observed. These disadvantages can be eliminated by implementing severe plastic deformation (SPD) in the volume of the metal. However, the low manufacturability of most SPD technologies constrains their use in industry. Therefore, the development and research of a new way to implement SPD in a continuous technological process, in particular during rolling in continuous mills, is an urgent scientific and technological problem.

The project proposes to develop new technological schemes of rolling rolls calibration, providing the implementation of intense shear deformation. According to the hypothesis proposed in the project non-monotonic nature of the metal flow during rolling in the new system of gauges will lead to a deep densification and elaboration of the metal structure at all levels of the metallophysical structure, which contributes to an integrated improvement in the mechanical and service properties of metal products. Establishment of regularities of formation of metal structure and properties under these conditions is the main scientific issue of the project.

The results obtained affect the development of theoretical and scientific foundations of technological methods of realization of intensive shear deformation in the field of longitudinal rolling and can be applied to justify new technology of industrial production of rolled metal products.

1)Nogaev Kairosh Abilovich – Candidate of Technical Sciences, Head of the Department of Technological Machines and Transport.

Scopus ID: 58065928300  

ResearcherID: KGS-4868-2024

https://orcid.org/0000-0003-1332-6352

2) Ashkeev Zhasulan Amanzholovich – Candidate of Technical Sciences, Associate Professor of the Department of Technological Machines and Transport

Scopus ID: 57205283781  

ResearcherID: U-8566-2018 

https://orcid.org/0000-0001-8992-3984

3) Akhmetova Gulzhanat Yesenzholovna – PhD, associate Professor of the Department of Metallurgy and Materials Science

4) Abishkenov Maxat – PhD, senior Lecturer of the Department of Technological Machines and Transport

Scopus ID: 57218196534  

ResearcherID:AAY-6294-2021   

https://orcid.org/0000-0002-7995-7651

5) Kydyrbaeva Saltanat Zhaisanbekovna – senior Lecturer of the Department of Technological Machines and Transport

6) Tavshanov, Ilgar – lecturer of the Department of Technological Machines and Transport

Scopus ID: 58203718700  

ResearcherID: JNR-8253-2023  

https://orcid.org/0000-0002-9427-9748

7) Kamarov Aman – doctoral student

1) Analytical review of the current state and trends in the development of technologies and methods of pressure treatment, providing a comprehensive improvement in the quality of metals. A measurable indicator is an analytical report on the current state and trends in the development of the problem.

2) Selection and justification of the rolling method in calibers. A measurable indicator is the rolling method, a computer model of the process and the interpretation of the simulation results.

3) Calibration calculation and development of design of rolling rolls and roll equipment, providing the realization of intense shear deformation. Measurable indicator – Technical documentation for the production of rolling rolls and roll tooling.

4) Development of experimental stand for rolling. Measurable indicator – Experimental stand for rolling.

5) Experimental studies of the rolling process. Measurable indicator – Experimental samples of metal and technological regimes of the process.

6) Establishment of regularities of formation of micromechanical properties of metal. The measurable indicator is the indicators of the complex of mechanical properties and the microstructure of the metal.

7) Development of technological modes of rolling in calibers. A measurable indicator is the Technological regulations for the production of rolled metal.

1) Various technological and constructive ways of implementing intense shear deformations in longitudinal rolling processes have been identified by methods of collecting, processing and analyzing primary information.

Processing and analysis of primary information revealed that intensive macro-shifts in the process of longitudinal rolling are achieved as a result of local deformation effects on the rolled metal and can be provided by various technological and constructive methods: the use of blanks and rolls with a wavy or corrugated surface, asymmetric rolling, uneven tightening of the roll along its thickness and width, etc. It is established that when rolling in calibrated rolls, it is possible to create conditions to ensure alternating metal flow in several passes due to simultaneous high-altitude compression and transverse shear in the deformation center. The technological difficulties of implementing intensive shear deformations in production conditions are analyzed, which determines the relevance of conducting research within the framework of this project.

2) A rolling method is proposed in the “oval-circle” gauge system, where the main axes of the oval in the calibers are located obliquely relative to the axis of the rolls. The angle of inclination of the main axis of the oval in caliber relative to the axis of the rolls is assumed to be γ = 35 °, which ensures the realization of a transverse shift in the deformation center simultaneously with high-altitude compression.

To substantiate the proposed rolling method in calibers that ensure the implementation of intense shear deformations, the modeling of the rolling process by the finite element method (FEM) in the DEFORM 3D software package was performed.

3) Computer modeling of the rolling process in an oval caliber with an inclined oval arrangement showed the non-monotonous nature of the metal flow due to the occurrence of vortex plastic flows, which causes the implementation of intense plastic deformations.

According to the results of modeling the stress-strain state, it was found that high stress intensity in a caliber with an inclined oval arrangement causes a higher level of intense shear deformation compared with rolling in a caliber with a traditional oval and provides intensive metal processing in the deformation focus.

In a caliber with an inclined oval, the proportion of stress intensity indicators above 180 MPa is 89.5%, whereas for a traditional caliber this indicator is almost 2.5 times lower (36.4%).

The indicators of the accumulated degree of shear deformation of more than 0.7 after rolling in a caliber with an inclined oval arrangement is 32.1%, which is 1.43 times higher than when rolling in a caliber with a traditional oval (22.43%).

4) The parameters of the shape change and geometric ratios of the calibers of the new oval-circle system for rolling in an experimental mill have been determined and design documentation for the manufacture of rolling rolls and roll wiring has been developed.

The parameters of the shape change and the size of the calibers were determined for experimental rolling of a roll from an initial round billet with a diameter of d_0 = 20 mm in the oval-circle caliber system in 4 passes with an extraction coefficient at each pass of µ = 1.3.

Working drawings of rolls and roll wiring have been developed for the DUO-150 laboratory rolling mill.

5) Based on the phenomenological Johnson-Mail-Avrami-Kolmogorov model (JMAK model), numerical simulation of the evolution of microstructure during the implementation of intense shear deformations during rolling in the oval-circle gauge system was performed. The microstructure parameters for AISI 316 steel were calculated using a dynamic recrystallization model. A comparative analysis of the values and the nature of the cross-section distribution of the average grain sizes of materials obtained during rolling according to the traditional and new scheme is carried out. Based on the simulation results, it was found that the implementation of intense shear deformations during rolling in the oval-circle gauge system provides more intensive and uniform grain grinding along the entire strip section compared to the traditional scheme. Confirmation of the heterogeneity of the mechanical properties of the metal in cross-section during rolling according to the traditional rolling scheme has been obtained. The effectiveness of the new rolling scheme in the study of the most defect-affected areas of the initial workpiece has been proven.

1. К. А. Ногаев, Ж. А. Ашкеев, М. Ж. Абишкенов, А. Сладковский , А. У. Камаров. Анализ напряженно-деформированного состояния при прокатке в овальном калибре, реализующем поперечный сдвиг // Наука и техника Казахстана. – 2023. – № 4. – С. 178-192. ISSN 2788-8770. –  https://doi.org/10.48081/ISPR9282

2) К.А. Ногаев, М.Ж. Абишкенов, И.С. Тавшанов, А.Д. Тайсагатов. Моделирование условий для определения энергосиловых параметров процесса прокатки в калибрах, реализующих интенсивные сдвиговые деформации  // Сборник трудов ХІІ Международной научно-практической конференции «Инновационные технологии и инжиниринг», посвященной 60-летию Карагандинского индустриального университета. Темиртау, 19-20 октября 2023 года. С. 532-536.

3) К.А. Ногаев, Ж.А. Ашкеев, Г.Е. Ахметова, С.Ж. Кыдырбаева. Обзор способов реализации интенсивных пластических деформации (ИПД) в процессах продольной прокатки  // Сборник трудов ХІІ Международной научно-практической конференции «Инновационные технологии и инжиниринг», посвященной 60-летию Карагандинского индустриального университета. Темиртау, 19-20 октября 2023 года. С. 544-547.