OBRABOTKAMETALLOV Vol. 25 No. 4 2023 102 TECHNOLOGY Evaluation of the bars’ multichannel angular pressing scheme and its potential application in practice Yuriy Loginov 1, 2, a, Yuliya Zamaraeva 1, 3, b, * 1 M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, 18 S. Kovalevskaya str., Ekaterinburg, 620137, Russian Federation 2 Ural Federal University named after the fi rst President of Russia B.N. Yeltsin, 19 Mira str., Yekaterinburg, 620002, Russian Federation 3JSC “Kamensk Uralsky Metallurgical Works”, 5 Zavodskaya str., Kamensk Uralsky, 623405, Russian Federation a https://orcid.org/0000-0002-7222-2521, j.n.loginov@urfu.ru; b https://orcid.org/0000-0002-2620-7064, zamaraevajulia@yandex.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2023 vol. 25 no. 4 pp. 90–104 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2023-25.4-90-104 ART I CLE I NFO Article history: Received: 28 August 2023 Revised: 07 September 2023 Accepted: 25 October 2023 Available online: 15 December 2023 Keywords: Angular pressing Low-plastic metals Pressing toolage Strain rate Strain Finite element method Funding The research was carried out as part of the state order on the subject “Pressure” (No. ААААА18-118020190104-3). Acknowledgements Research was partially conducted at core facility “Structure, mechanical and physical properties of materials”. ABSTRACT Introduction. Deformation of low-plastic materials requires a high degree of compressive stress. This requirement is implemented, for example, in the process of equal channel angular pressing (ECAP). However, the products obtained by the ECAP method have a cross-section identical to the initial blank, which is one of the disadvantages of this method. The method of nonequal channel angular pressing (NECAP), in contrast to ECAP, makes it possible to change the shape of the initial blank towards closer to the shape of the fi nished product. However, the well-known NECAP device allows obtaining products only in the form of a thin strip of rectangular cross-section. Well-known devices for multichannel pressing of non-angular type also have a disadvantage — it is implemented only on horizontal type presses, where it is possible to receive long products on the workshop areas. The aim of the work is the evaluation of the bars’ multichannel angular pressing scheme, combining a change in the shape of the initial workpiece in cross-section, as well as the accumulation of a high level of strain during deformation. Research methods: fi nite element modeling using the DEFORM software module. Results and discussion. The paper considers the scheme of the angular pressing process with the use of a device that allows, for example, to obtain magnesium bars with a diameter of d = 4.1 mm with the number of matrix channels n = 3 from a blank of round cross-section. The container of this device in its lower part has a rectangular groove where the matrix is inserted. Modeling of the process under study using a matrix with the axes of its channels located in the plane of the orthogonal axis of the container and, in the fi rst variant, along the axis of a rectangular groove, and in the second variant, along the radius of the container, allowed us to estimate the distribution of the average stress. It is established that the metal of the blank in both variants of the deformation process is aff ected by compression stresses at a high level (−1,600 MPa). The assessment of the degree of deformation of the pressed bars allowed us to fi nd out that at the initial stage of both process variants, the maximum strain degree can reach 2.6, and at the steady stage it reaches 5.0. It is established that in the case of the fi rst variant of the matrix, the strain level along the length of the bars is lower than when using the second variant of the matrix. The diff erence reaches 20 %. By evaluating the distribution of the strain degree in the cross section of the pressed bars near the deformation site, it was found that in the case of the fi rst variant of the matrix, the pressed bars of the fi rst and third channels have an uneven dimensions, and the greater value of the strain degree is on the peripheral part of the rods from the side bordering the central bar. This diff erence in the strain degree reaches 20 %. When placing the second version of the matrix, this unevenness decreases to 12 %. Thus, in the case of using a matrix with the arrangement of the channel axes along the radius of the container, the strain degree is distributed more evenly compared to the strain degree when using a matrix with the arrangement of the channel axes along the axis of a rectangular groove. For citation: Loginov Yu.N., Zamaraeva Yu.V. Evaluation of the bars’ multichannel angular pressing scheme and its potential application in practice. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2023, vol. 25, no. 4, pp. 90–104. DOI: 10.17212/1994-6309-2023-25.4-90-104. (In Russian). ______ * Corresponding author Zamaraeva Yuliya V., Researcher M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, 18 S. Kovalevskaya str., 620137, Ekaterinburg, Russian Federation Tel.: +7 (950) 200-56-79, e-mail: zamaraevajulia@yandex.ru
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