AN INVESTIGATION ON FRICTION SPOT WELDING IN AA6181-T4 ALLOY
INVESTIGAÇÃO DO PROCESSO DE SOLDAGEM POR FRICÇÃO POR PONTO PARA A LIGA AA6181-T4
Parra, Bruno; Saccon, Vinicius Toledo; Alcântara, Nelson Guedes de; Rosendo, Tonilson; Santos, Jorge Fernandes dos
http://dx.doi.org/10.4322/tmm.2011.029
Tecnol. Metal. Mater. Min., vol.8, n3, p.184-190, 2011
Abstract
Friction spot welding is a new solid state welding process, invented and patented by the GKSS Research Centre GmbH in Germany, suitable for spot joining lightweight low melting point materials such as Al and Mg alloys. The process is performed with an especially designed rotating tool (comprised by a clamping ring, sleeve, and pin) that creates a joint between sheets in overlap configuration by means of frictional heat and mechanical work. The result is a spot welded lap joint with minimal material loss and a flat surface with no keyhole. In this work the application of Friction Spot Welding for spot joining the AA6181-T4 is investigated. Different rotational speeds (1900 to 2900 rpm) and welding times (2 to 3.4 s) were tested with the objective of finding the best suited ones for producing high quality joints in terms of microstructure and mechanical performance. Welds with strength in the order of 6.8 kN were obtained with high reproducibility. The results also show that geometric elements of the weld play an important role on the fracture mechanisms and hence on the mechanical performance of the joints. In sum, the results reveal the potential of this process for industrial applications.
Keywords
Friction, Aluminnum, Welding.
Resumo
Soldagem por Ponto por Fricção (SPF) é um novo processo de solda ponto no estado sólido patenteado no Centro de Pesquisas alemão GKSS, que permite se unir pontualmente ligas metálicas com baixo ponto de fusão como as ligas de Al e Mg. O processo é realizado com uma ferramenta especialmente desenvolvida (composta por anel de retenção, camisa e pino) que une as partes em configuração sobreposta por calor de fricção e deformação mecânica. O resultado é uma junta soldada sobreposta com mínima perda de material e superfície lisa sem buracos deixados pela ferramenta. Neste trabalho, é investigado o processo de SPF para a união da liga AA6181-T4. Diferentes velocidades rotacionais (1900 a 2900 rpm) e tempos de soldagem (2 a 3,4 s) foram testados com o objetivo de se encontrar as melhores condições de se produzir juntas de qualidade em termos de microestrutura e desempenho mecânico. Foram obtidas soldas com resistência na ordem de 6,8 kN, com alta reprodutibilidade. Os resultados também mostram que elementos geométricos das juntas têm importante papel nos mecanismos de fratura e, portanto no desempenho mecânico das juntas. Em suma, os resultados revelam potencial do processo para aplicações industriais.
Palavras-chave
Fricção, Alumínio, Soldagem
Referências
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3 SCHILLING, C.; SANTOS, J. F. Method and device for linking at least two adjoining work pieces by friction welding. International Patent Publication WO/2001/036144. 2005.
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5 ROSENDO T. et al. Investigation of friction spot welding of aeronautic AA2024-T3 and AA7075-T6 alloy. In: INTERNATIONAL CONFERENCE ON TRENDS IN WELDING RESEARCH, 8., Pine Mountain, Georgia, USA. Proceedings… [S.l.: s.n.t.], 2008.
6 SCHILLING, C.; STROMBECK, A. V.; SANTOS, J. F. Friction spot welding: new joining process for spot connections. Geesthacht: GKSS Research Center, 2001. (GKSS Research Center Internal Report)
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9 DEUTSCHES INSTITUT FÜR NORMUNG. DIN EN ISO 14273, 2002-03. Specimens dimensions and procedure for shear testing resistance spot, seam and embossed projection welds. Berlin, 2002-3.
10 SILVA, A. M. et al. Friction based spot welding processes: literature review. Welding and Material Testing, 3rd quarter, 2007.
11 SILVA, A.M. et al. Preliminary investigations on microstructural features and mechanical performance of friction spot welding of aluminium alloys. In: IIW INTERNATIONAL SEMINAR ON FRICTION BASED SPOT WELDING PROCESSES, 2007, Geesthacht. Geesthacht: GKSS Research Centre, 2007.
12 GERLICH, A. et al. Effect of welding parameters on the strain rate and microstructure of friction stir spot welded 2024 aluminium alloy. Journal of Material Science, v. 2, n. 42, p. 5589-601, Apr. 2007.
13 OLEA, C. et al. A sub-structural analysis of friction stir welded joints in an AA 6056 Al-alloy in T4 and T6 temper conditions. Materials Science and Engineering A, v. 454-455, p. 52-62, 2007
14 OLEA, C. Influence of energy input in friction stir welding on structure evolution and mechanical behaviour of precipitation- -hardening in aluminium alloys (AA2024-T351, AA6013-T6 and AL-Mg-Sc). 2008. 159 p. Thesis (Doctor) − Mechanical Engineering Department, University of Bochum, Bochum, Germany, 2008.
15 NORTH, T. et al. Understanding friction welding. In: INTER-UNIVERSITY RESEARCH SEMINAR (IURS 200), 2005, Beijing, China. Proceedings… [S.l.: s.n.t.], 2005.
16 KOCH, N. et al. An investigation of friction spot welding of thin aluminum sheets. In: AEROMAT 2003; ADVANCED AEROSPACE MATERIALS & PROCESSES CONFERENCE AND EXPOSITIONS, 14., 2003, Dayton, USA. Proceedings… [S.l.: s.n.t.], 2003.
17 ALLEN, C.; ARBEGAST, W. J. Evaluation of friction spot welds in aluminum alloys. In: SAE 2005 WORLD CONGRESS & EXHIBITION, 2005, Detroit, MI. (Technical paper 2005-01-1252). Disponível em:. Acesso em: 10 mar. 2009.
2 SCHILLING, C.; SANTOS, J. F. Verfahren und Vorrichtung zum Verbinden von wenigstens zwei aneinanderliegenden Werkstücken nach der Methode des Reibschweissens. Patent Application Amtl. Az. 199 55737.3. 1999.
3 SCHILLING, C.; SANTOS, J. F. Method and device for linking at least two adjoining work pieces by friction welding. International Patent Publication WO/2001/036144. 2005.
4 ROSENDO T. et al. Friction spot welding of AA2024 T3 aluminium alloy a feasibility study. In: EUROMAT 2007, Nuremberg, Germany. Proceedings… [S.l.: s.n.t.], 2007.
5 ROSENDO T. et al. Investigation of friction spot welding of aeronautic AA2024-T3 and AA7075-T6 alloy. In: INTERNATIONAL CONFERENCE ON TRENDS IN WELDING RESEARCH, 8., Pine Mountain, Georgia, USA. Proceedings… [S.l.: s.n.t.], 2008.
6 SCHILLING, C.; STROMBECK, A. V.; SANTOS, J. F. Friction spot welding: new joining process for spot connections. Geesthacht: GKSS Research Center, 2001. (GKSS Research Center Internal Report)
7 HOFMANN, A. Deep drawing of process optimized blanks. Journal of Materials Processing Technology, v. 119, n. 1-3, p. 127-32, Dec. 2001.
8 KNOLL, H. Untersuchungen von Reibpunktschweiβverbindungen in Aluminiumlegierungen. 2007. 212 p. Thesis (Bachelor) − Fachhochschule Düsseldorf, University of Applied Sciences, Düsseldorf, Germany, 2007.
9 DEUTSCHES INSTITUT FÜR NORMUNG. DIN EN ISO 14273, 2002-03. Specimens dimensions and procedure for shear testing resistance spot, seam and embossed projection welds. Berlin, 2002-3.
10 SILVA, A. M. et al. Friction based spot welding processes: literature review. Welding and Material Testing, 3rd quarter, 2007.
11 SILVA, A.M. et al. Preliminary investigations on microstructural features and mechanical performance of friction spot welding of aluminium alloys. In: IIW INTERNATIONAL SEMINAR ON FRICTION BASED SPOT WELDING PROCESSES, 2007, Geesthacht. Geesthacht: GKSS Research Centre, 2007.
12 GERLICH, A. et al. Effect of welding parameters on the strain rate and microstructure of friction stir spot welded 2024 aluminium alloy. Journal of Material Science, v. 2, n. 42, p. 5589-601, Apr. 2007.
13 OLEA, C. et al. A sub-structural analysis of friction stir welded joints in an AA 6056 Al-alloy in T4 and T6 temper conditions. Materials Science and Engineering A, v. 454-455, p. 52-62, 2007
14 OLEA, C. Influence of energy input in friction stir welding on structure evolution and mechanical behaviour of precipitation- -hardening in aluminium alloys (AA2024-T351, AA6013-T6 and AL-Mg-Sc). 2008. 159 p. Thesis (Doctor) − Mechanical Engineering Department, University of Bochum, Bochum, Germany, 2008.
15 NORTH, T. et al. Understanding friction welding. In: INTER-UNIVERSITY RESEARCH SEMINAR (IURS 200), 2005, Beijing, China. Proceedings… [S.l.: s.n.t.], 2005.
16 KOCH, N. et al. An investigation of friction spot welding of thin aluminum sheets. In: AEROMAT 2003; ADVANCED AEROSPACE MATERIALS & PROCESSES CONFERENCE AND EXPOSITIONS, 14., 2003, Dayton, USA. Proceedings… [S.l.: s.n.t.], 2003.
17 ALLEN, C.; ARBEGAST, W. J. Evaluation of friction spot welds in aluminum alloys. In: SAE 2005 WORLD CONGRESS & EXHIBITION, 2005, Detroit, MI. (Technical paper 2005-01-1252). Disponível em:
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