Abstract
Grain refinement is an important possibility to enhance the weldability of aluminium weld metal that is usually defined by its susceptibility to solidification cracking. In this study, grain refinement was achieved through the addition of commercial grain refiner containing titanium and boron to the GTA weld metal of aluminium alloy 6082. The weld metal mean grain size could be reduced significantly from about 70 μm to a saturated size of 21 μm with a change in grain shape from columnar to equiaxed. The grain refinement prevented the formation of centreline solidification cracking that was present only in welds with unrefined grain structure. A variation of torch speed led to a strong change of solidification parameters such as cooling rate that was measured in the weld metal and the corresponding solidification rate and thermal gradient. The ratio thermal gradient/growth rate (G/R) decreased from 50 K s/mm2 (high torch speed) to 10 K s/mm2 (low torch speed). However, the variation of torch speed did not change the tendency for solidification cracking. The microstructure of unrefined and completely refined weld metal was compared. The observed change in size and distribution of the interdendritic phases was related to the change in susceptibility to solidification cracking.
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References
Dvornak M.J., Frost R.H. and Olson D.L.: Influence of solidification kinetics on aluminum weld grain refinement, Welding Journal, 1991, vol. 70, no. 10, pp. 271s–276s.
Pumphrey W.I. and Jennings P.H.: A consideration of the nature of brittleness and temperature above the solidus in castings and welds in aluminum, Journal of the Institute of Metals, 1948, vol. 75, pp. 235–256.
Beckert M. and Herold H.: Kompendium der Schweißtechnik, Band 3: Eignung metallischer Werkstoffe zum Schweißen, Compendium of welding technology, vol. 3: Weldability of metallic materials, 2nd edition, DVS-Verlag, 2002 (in German).
Rappaz M., Drezet J.-M. and Gremaud M.: A new hot-tearing criterion, Metallurgical and Materials Transactions A, 1999, vol. 30, no. 2, pp. 449–455.
Mathers G.: The welding of aluminium and its alloys, Woodhead Publishing, 2002.
Jennings P.H., Singer A.R.E. and Pumphrey W.I.: Hot-shortness of some high-purity alloys in the systems aluminium-copper-silicon and aluminium-magnesium-silicon, Journal of the Institute of Metals, 1948, vol. 74, pp. 227–248.
Mousavi M.G., Cross C.E., Grong Ø. and Hval M.: Controlling weld metal dilution for optimised weld performance in aluminium, Science and Technology of Welding and Joining, 1997. vol. 2, no. 6, pp. 275–278.
Seshagiri P.C., Nair B.S., Reddy G.M., Rao K.S., Bhattacharya S.S. and Rao K.P.: Improvement of mechanical properties of aluminium-copper-alloy (AA2219) GTA welds by Sc addition, Science and Technology of Welding and Joining, 2008, vol. 13, no. 2, pp. 146–158.
Matsuda F., Nakata K., Tsukamoto K. and Arai K.: Effect of additional element on weld solidification crack susceptibility of Al-Zn-Mg Alloy (Report II), Transactions of the Joining and Welding Research Institute, 1983, vol. 12, no. 2, pp. 253–262.
Dvornak M.J., Frost R.H. and Olson D.L.: The weld-ability and grain refinement of Al-2.2Li-2.7Cu, Welding Journal, 1989, vol. 68, no. 8, pp. 327s–335s.
Mousavi M.G., Cross C.E. and Grong Ø.: Effect of scandium and titanium-boron on grain refinement and hot cracking of aluminium alloy 7108, Science and Technology of Welding and Joining, 1999, vol. 4, no. 6, pp. 381–388.
Janaki Ram G.D., Mitra T.K., Raju M.K. and Sundaresan S.: Use of inoculants to refine weld solidification structure and improve weldability in type 2090 Al-Li alloy, Materials Science and Engineering A, 2000, vol. 276, no. 1–2, pp. 48–57.
Spittle J.A. and Cushway A.A.: Influences of superheat and grain structure on hot-tearing susceptibilities of Al-Cu alloy castings, Metals Technology, 1983, vol. 10, no. 1, pp. 6–13.
Schneider W., StJohn D.H. and Greer A.L.: Solidification processing of foundry alloys: mechanism of grain refinement of aluminium — Almost all you need to know, Proceedings of the 11th International Conference on Aluminium Alloys, Their Physical and Mechanical Properties, September 2008, Aachen, vol. 1, pp. 383–392.
Crossley F.A. and Mondolfo L.F.: Mechanism of grain refinement in aluminum alloys, Journal of Metals, 1951, vol. 191, pp. 1143–1148.
Cibula, A.: The mechanism of grain refinement of sand castings in aluminium alloys, Journal of the Institute of Metals, 1949, vol. 76, no. 4, pp. 321 et seqq.
Bäckerud L., Król E. and Tamminen J.: Solidification characteristics of aluminium alloys, vol. 1, Skanaluminium Universitetsforlaget AS, 1986.
McCartney D.G.: Grain refining of aluminium and its alloys using inoculants, International Materials Reviews, 1989, vol. 34, no. 5, pp. 247–260.
Easton M. and St John D.: An analysis of the relationship between grain size, solute content, and the potency and number density of nucleant particles, Metallurgical and Materials Transactions A, 2005, vol. 36, no. 7, pp. 1911–1920.
Koteswara Rao S. R., Madhusudhana Reddy G., Kamaraj M. and Prasad Rao K.: Grain refinement through arc manipulation techniques in Al-Cu alloy GTA welds, Materials Science & Engineering A, 2005, vol. 404, no. 1–2, pp. 227–234.
Pearce B.P. and Kerr H.W.: Grain refinement in magnetically stirred GTA welds of aluminum alloys, Metallurgical and Materials Transactions B, 1981, vol. 12, no. 3, pp. 479–486.
Janaki Ram G.D., Mitra T.K., Shankar V. and Sundaresan S.: Microstructural refinement through inoculation of type 7020 Al-Zn-Mg alloy welds and its effect on hot cracking and tensile properties, Journal of Materials Processing Technology, vol. 142, no. 1, pp. 174–181.
Schempp P., Cross C.E., Schwenk C. and Rethmeier M.:Weld Metal Grain Refinement of Aluminium Alloy 5083 through Controlled Additions of Ti and B, MP Materials Testing, 2011, vol. 53, no. 10, pp. 604–609.
ASTM E 112-96, Standard Test Methods for Determining Average Grain Size, ASTM, USA.
ASTM E 1382-97, Standard Test Methods for Determining Average Grain Size Using Semiautomatic and Automatic Image Analysis, ASTM, USA.
Aluminium-Taschenbuch (Aluminium Handbook), 14th edition, Aluminium-Zentrale, 1983 (in German).
Maxwell I. and Hellawell A.: A Simple Model for Grain Refinement during Solidification, Acta Metallurgica, 1975, vol. 23, no. 2, pp. 229–237.
Hunt J.D.: Steady State Columnar and Equiaxed Growth of Dendrites and Eutectic, Materials Science and Engineering, 1984, vol. 65, no. 1, pp. 75–83.
Flemings M.C.: Solidification Processing, Metallurgical Transactions B, 1974, vol. 5, no. 10, pp. 2121–2134.
Ganaha T., Pearce B.P. and Kerr H.W.: Grain Structures in Aluminium Alloy GTA Welds, Metallurgical Transactions A, 1980, vol. 11, no. 8, pp. 1351–1359.
Kou S. and Le Y., Welding Parameters and the Grain Structure of Weld Metal — A Thermodynamic Consideration, Metallurgical Transactions A, 1988, vol. 19, no. 4, pp. 1075–1082.
Tiller W.A., Jackson K.A., Rutter J.W. and Chalmers B.: The Redistribution of Solute Atoms during the Solidification of Metals, Acta Metallurgica, 1953, vol. 1, no. 4, pp. 428–437.
Dvornak M.J., Frost R.H. and Olson D.L.: Effects of Grain Refinement of Aluminum Weldability, in: Weldability of Materials, ASM, 1990, pp. 289-295.
Kou S.: Welding Metallurgy, John Wiley & Sons, 2003.
Cross C.E., Tack W.T. and Loechel L.W.: Aluminium Weldability and Hot Treating Theory, in: Weldability of Materials, ASM, 1990, pp. 275-282.
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Schempp, P., Cross, C.E., Schwenk, C. et al. Influence Of Ti And B Additions On Grain Size And Weldability Of Aluminium Alloy 6082. Weld World 56, 95–104 (2012). https://doi.org/10.1007/BF03321385
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DOI: https://doi.org/10.1007/BF03321385