Effect of Friction Stir Welding Mode and its Direction Relative to the Rolling Direction of 2024 Alloy on the Structure and Mechanical Properties of its Weld Joints

OBRABOTKAMETALLOV Vol. 22 No. 4 2020 121 MATERIAL SCIENCE Effect of Friction Stir Welding Mode and its Direction Relative to the Rolling Direction of 2024 Alloy on the Structure and Mechanical Properties of its Weld Joints Alexey Ivanov 1, 2, а , * , Valery Rubtsov 1, 2, b , Evgeny Kolubaev 1, 2, c , Vladimir Bakshaev 3, d , Ivan Ivashkin 3, e 1 Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, 2/4 pr. Akademicheskii, Tomsk, 634055, Russian Federation 2 Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russian Federation 3 SESPEL Cheboksary enterprise, CJSC, 36 Leningradskaya st., Cheboksary, 428021, Chuvash Republic, Russian Federation а https://orcid.org/0000-0001-8959-8499, ivan@ispms.ru , b https://orcid.org/0000-0003-0348-1869, rvy@ispms.ru, c https://orcid.org/0000-0001-7288-3656, eak@ispms . ru, d https://orcid.org/0000-0001-9777-0164, bakshaevva@mail.ru , e https://orcid.org/0000-0001-8808-2183, ivashkin_in@mail.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2020 vol. 22 no. 4 pp. 110–123 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2020-22.4-110-123 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 01 September 2020 Revised: 09 September 2020 Accepted: 17 September 2020 Available online: 15 December 2020 Keywords : Friction stir welding Welding condition parameters Rolling direction Aluminum alloy Funding This work was performed within the frame of integrated project « Building of manufacturing of high-tech large- sized equipment for intelligent adaptive friction stir welding for aerospace and transport industries of the Russian Federation» (grant agreement from 22.11.2019 № 075-11- 2019-033), implemented by SESPEL Cheboksary enterprise, CJSC, NETI and ISPMS SB RAS with the fi nancial support of the Ministry of Education and Science of Russia in the context of Russian Government decree from 09.04.2010 № 218. ABSTRACT Introduction. Friction stir welding conditions determines character of thermomechanical impact on welded material, so a critical alteration of even one of condition parameters can result in formation of defects and strength decrease of welded joint. Also an important factor is an orientation of welded material relative to a welding direction since it determines kinetics of material deformation and consequently its fi nal structure and properties. Research efforts of friction stir welding properties generally consist in analysis of fi nal properties of obtained weld joints and its correlation with parameters of welding condition. But to solve a problem of obtaining of weld joints with strength and quality, it’s also important to estimate a welded material resistance to deformation from welding tool impact which could be achieved by monitoring a number of parameters directly in process of welding. The purpose of the work is to research an impact of welding condition parameters and an orientation of welded material’s structure on friction stir welding process behavior and also on structure and strength of weld joints of 2024 aluminum alloy. Results and discussion. By monitoring the torque and welding force, it is shown that as the tool penetration force increases, the material’s resistance to deformation increases. When welding is longitudinal to the direction of base metal rolling a torque and a welding force parameters decreases in value of 5-20%. An increase of welding speed provides a growing of material resistance to welding tool movement, at that, a direction of welding doesn’t have a signi fi cant impact. With an increase of welding tool rotational speed, a material resistance to deformation decreases, a welding temperature grows and it results in growing of material’s plasticization degree and in improvement of its mass transfer conditions. It is also shown that the welding conditions, which allows welding the 2024 alloy at a temperature of 450 – 500 º С , provides the degree of plasticization of the material, at which welded joints with a high-quality structure and high mechanical properties are obtained. In this conditions a direction of welding in relation to the direction of base metal rolling has an impact: when welding is longitudinal to the direction of rolling the tensile strength of weld joints reaches a value of 92 %, and when welding is transverse – 95% of base material tensile strength. For citation: Ivanov A.N., Rubtsov V.E., Kolubaev E.A., Bakshaev V.A., Ivashkin I.N. Effect of friction stir welding mode and its direction relative to the rolling direction of 2024 alloy on the structure and mechanical properties of its weld joints. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2020, vol. 22, no. 4, pp. 110–123. DOI: 10.17212/1994-6309-2020-22.4- 110-123. (In Russian). ______ * Corresponding author Ivanov Alexey N., Ph.D. (Engineering), Scienti fi c associate Institute of Strength Physics and Materials, Science of Siberian Branch of Russian Academy of Sciences, 2/4 pr. Akademicheskii, 634055, Tomsk, Russian Federation Tel.: +7 (382) 228-68-63, e–mail: ivan@ispms.tsc.ru