PRACTICAL VALIDATION AND HEAT FLOW MODELING OF FSW’ED ALUMINUM ALLOYS

Öz

This paper describes the application of the CFD code, Comsol Multiphysics 3.5a, to modeling the three-dimensional heat and metal flow in friction stir welding (FSW) of AA6061-T6 aluminum alloy. The simulation consists of two aluminum plates to be welded, tool and its shoulder. Heat transfer and non-newtonian flow equations were solved simultaneously. The convective heat transfer coefficients underneath the welded plates and the heat given to the system by the tool shoulder were determined by the help of a simple and practical thermal validation. The heat flow along the plates is depicted with changing welding conditions. The flow around the tool pin and shoulder was shown for several different tool rotation rates. This kind of practical validation method helps the welding engineer to simulate nearly all the possible welding conditions without performing expensive experiments. Information obtained from the presented validation and the model can save a lot of engineering hours

Anahtar Kelimeler

• FSW, Modeling, Aluminum Alloy

SÜRTÜNME KARIŞTIRMA KAYNAĞI YAPILMIŞ ALÜMİNYUM ALAŞIMLARININ ISI AKIŞININ MODELLEMESİ VE PRATİK DOĞRULAMASI

Öz

Bu makalede AA 6061-T6 alüminyum alaşımının sürtünme karıştırma kaynağının Comsol Multiphysics 3.5a ile yapılan üç boyutlu modellemesi anlatılmıştır. Simülasyon kaynak edilecek iki alüminyum levhasını, kaynak takımını ve kaynak takımının omuz kısmını içermektedir. Isı transferi ve Newtonyen olmayan akış denklemleri aynı anda çözülmüştür. Kaynak edilen plakaların altındaki taşınım ısı transfer katsayısı ve kaynak takımının omuz kısmı tarafından sisteme verilen ısı miktarı basit ve pratik bir ısıl doğrulama yöntemiyle belirlenmiştir. Kaynak edilen plakalar boyunca oluşan ısı akışı değişik kaynak koşulları için gösterilmiştir. Kaynak takımı omzu ve ucu etrafında oluşan metal akışı değişik takım dönme hızları için gösterilmiştir. Bu çeşit bir pratik doğrulama yöntemi kaynak mühendisine neredeyse mümkün olabilecek bütün kaynak koşullarını simüle edebilecek sağlayabilmektedir. Sunumu yapılan doğrulama ve model sayesinde mühendislik zamanından tasarruf yapılabilecektir. imkanı pahalı deneyler yapmadan

Anahtar Kelimeler

• Sürtünme Karıştırma Kaynağı, Modelleme, Alüminyum Alaşımı

Kaynakça

1. [1] Thomas, M. W. , Nicholas, J., Needham, J. C., Murch, M. G., Templesmith, P. and Dawes, C. J. (1995) ‘Friction stir butt welding’, GB Patent Application no. 9125978- 8, 1991; US Patent no. 5460317.
2. [2] Roy, B. S., Saha, S. C. and Barma, J. D. (2012) 3-D Modeling & Numerical Simulation of Friction Stir Welding Process, Adv. Mater. Rsrch., 488-489, 1189–1193.
3. [3] Chao, Y. J., Qi, X. and Tang, W. (2003) Heat Transfer in Friction Stir Welding—Experimental and numerical studies, Int. J. Manuf. Sci. Eng., 125, (1), , 138–145.
4. [4] Song, M. and Kovacevic R. (2004) Heat transfer modelling for both workpiece and tool in the FSW process a coupled model, Proc. Inst. Mech. Eng. B, 218B, 17–33.
5. [5] Song, M. and Kovacevic, R. (2003) Thermal modeling of friction stir welding in a moving coordinate, Int. J. Mach. Tools Manuf., 43, 605–615.
6. [6] Song, M. and Kovacevic, R. (2003) Numerical and experimental study of the heat transfer process in friction stir welding, Proc. Inst. Mech. Eng. B, 217B, , 73–85.
7. [7] Schmidt, H. B. and Hattel, J. H. (2004), Heat Source Models in Simulation of Heat Flow in Friction Stir Welding, Int. J. of Offsh. Pol. Eng., 14, (4), 296–304
8. [8] Schmidt, H. B. and Hattel, J. H. (2008) Thermal and Material Flow modelling of Friction Stir Welding with COMSOL, Excerpt from the Proceedings of the COMSOL Conference, Hannover (CD-ROM).

9. [9] Colegrove,P. , Painter, M. , Graham, D. and Miller, T. (2000) 3D Flow and Thermal Modeling of the FSW Process, 2nd Int. Symp. of FSW Proc. 2nd Int. Symp. on ‘Friction stir welding’, Gothenburg, Sweden, (CDROM), TWI Ltd.
10. [10] Reynolds, A. P. (2008) Flow visualization and simulation in FSW, Scripta Mat., 58, 338–342.
11. [11] Long, T. and Reynolds, A. P. (2006) Parametric studies of friction stir welding by commercial fluid dynamics simulation, Sci. Technol. Weld. Join., 11, (2), 200– 208.
12. [12] Colegrove, P.A. and Shercliff, H. R. (2004) Two-dimensional CFD modelling of flow round profiled FSW tooling, Sci. Technol. Weld. Join., 9, (6), 483–492.
13. [13] Colegrove, P.A. and Shercliff, H. R. (2006) CFD modelling of friction stir welding of thick plate 7449 aluminium alloy, Sci. Technol. Weld. Join., 11, (4), 429–441.
14. [14] Seidel, T. U. and Reynolds, A. P. (2003) Two-dimensional friction stir welding process model based on fluid mechanics, Sci. Technol. Weld. Join., 8, (3), 175–183.
15. [15] Hattel, J.H., Schmidt, H.B. and Tutum, C. Thermomechanical Modelling of Friction Stir Welding’ Trends in Welding Research, Proc. 8th Int. Conf. 1–10
16. [16] Schmidt, H. B. and Hattel, J. H. (2008) Thermal modelling of friction stir welding, Scripta Mater., 58, 332–337.
17. [17] Nandan, R. (2008) Computational modeling of heat transfer and visco-plastic flow in friction stir welding, PhD thesis, The Pennsylvania State University, PA, USA, 2008, 17-25.
18. [18] Nandan, R., Roy, G. G. and Debroy, T. (2006) Numerical simulation of three-dimensional heat transfer and plastic flow during friction stir welding, Metall. Mater. Trans. A: Phys. Metall. Mater. Sci., 37, (4), 1247–1259.
19. [19] Dörfler, S. M. (2008) Advanced modeling of friction stir welding – improved material model for aluminum alloys and modeling of different materials with different properties by using the level set method, Excerpt from the Proceedings of the COMSOL Conference, Hannover (CD-ROM).
20. [20] Chao, Y. J., Qi, X. and Tang, W. (2003) Heat Transfer in Friction Stir Welding—Experimental and numerical studies, Int. J. Manuf. Sci. Eng., 125, (1), , 138–145.
21. [21] Cambridge University http://wwwmaterials.eng.cam.ac.uk/FSW_Benc hmark/, accessed on 1.3.2013.
22. [22] Atallah, M. M. (2007) Microstructure-property development in friction stir welds of aluminium-based alloys’, PhD thesis, University of Birmingham, UK.
23. [23] Hu, J., Guo, H.and Tsai, H. L. (2008) Weld pool dynamics and the formation of ripples in 3D gas metal arc welding’, Int. J.Heat and Mass Transfer, 51, 2537–2552.
24. [24] Hu, J., Tsai, H. L. and Wang, P. C. (2006) Numerical modeling of GMAW arc’, Adv. Computer, Information, Sys. Sci. Eng., 69–74.
25. [25] Savas, A. and Ceyhun, V. (2012) Finite element analysis of GTAW arc under different shielding’, Comp. Mater. Sci., 51, (1), 53-71.
26. [26] Carbone, R., Langella, A. and Nele, N. (2007) Numerical modelling of a time – dependent friction stir welding process with a moving tool using Comsol script’, Excerpt from the Proceedings of the COMSOL Users Conference, Grenoble (CD-ROM).
27. [27] Colegrove, P. (2006) Modelling the heat generation, temperature and microstructure of friction stir welding using comsol multiphysics, Excerpt from the Proceedings of the COMSOL Users Conference, Birmingham (CD-ROM).
28. [28] COMSOL website http://www.comsol.com/products/ 3.5/, accessed on 3.3.2014.
29. [29] Atharifar, H., Lin, D. and Kovacevic, R. (2009) Numerical and experimental investigations on the loads carried by the tool during friction stir welding, J. Mater. Eng. Perform., 18, (4), 339–350.
30. [30] Hilgert, J., Huetsch, L.L., dos Santos, J.F. and Huber, N. (2010) Material Flow around a Bobbin Tool for Friction Stir Welding.” Excerpt from the Proceedings of the COMSOL Conference, Paris (CDROM).
31. [31] Nandan, R., Roy, G.G., Lienert, T.J. and Debroy, T. (2007) Threedimensional heat and material flow during friction stir welding of mild steel, Acta Mat., 55, 883–895.