Effect of Helium-Argon Mixtures on the Heat Transfer and Fluid Flow in Gas Tungsten Arc Welding

Authors: A. Traidia, F. Roger, A. Chidley, J. Schroeder, T. Marlaud

Abstract:

A transient finite element model has been developed to study the heat transfer and fluid flow during spot Gas Tungsten Arc Welding (GTAW) on stainless steel. Temperature field, fluid velocity and electromagnetic fields are computed inside the cathode, arc-plasma and anode using a unified MHD formulation. The developed model is then used to study the influence of different helium-argon gas mixtures on both the energy transferred to the workpiece and the time evolution of the weld pool dimensions. It is found that the addition of helium to argon increases the heat flux density on the weld axis by a factor that can reach 6.5. This induces an increase in the weld pool depth by a factor of 3. It is also found that the addition of only 10% of argon to helium decreases considerably the weld pool depth, which is due to the electrical conductivity of the mixture that increases significantly when argon is added to helium.

Keywords: GTAW, Thermal plasmas, Fluid flow, Marangoni effect, Shielding Gases.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1059787

References:

[1] W.H. Kim, and S.J. Na, "Heat and fluid flow in pulsed current GTA weld pool", in Int. J. Heat Mass Tran., 1998, vol 41, pp. 3213-3227.
[2] H.G. Fan, H.L. Tsai, and S.J. Na, "Heat transfer and fluid flow in a partially or fully", in Int. J. Heat Mass Tran., 2001, vol 44, pp. 417-428.
[3] F. Lu, S. Yao, S. Lou, and Y. Li, "Modeling and finite element analysis on GTAW arc and weld pool", in Comput. Mater. Sci., 2004, vol 29, pp. 371-378.
[4] A. Traidia, F. Roger, and E. Guyot, "Optimal parameters for pulsed gas tungsten arc welding in partially", in Int. J. Therm. Sci., 2010, vol 49, pp. 1197-1208.
[5] M. Tanaka, and J.J. Lowke, "Predictions of weld pool profiles using plasma physics", in J. Phys. D: Appl. Phys., 2007, vol 40, pp. R1-R23.
[6] A.B. Murphy, M. Tanaka, S. Tashiro, T. Sato, and J.J. Lowke, "A computational investigation of the effectiveness of different shielding gas mixtures for arc", in J. Phys. D: Appl. Phys., 2009, vol 42, 115205.
[7] A.B. Murphy et al, "Modeling of thermal plasmas for arc welding_ the role of the shielding gas properties and of metal vapour ", in J. Phys. D: Appl. Phys., 2009, vol 42, 194006.
[8] P. Sahoo, T. DebRoy, M.T. McNallan, "Surface tension of binary metal surface active solute systems under conditions relevant to welding metallurgy", in Metall. Trans. B., 1988, vol 19B, pp. 483-491.
[9] F. Lago, JJ. Gonzalez, P. Freton, and A. Gleizes. "A numerical modelling of an electric arc and its interaction with the anode: Part I. The two-dimensional model", 2004, in J. Phys. D: Appl. Phys. Vol 37, pp. 883-897.
[10] JJ. Gonzalez, F. Lago, P. Freton, M. Masquère, and X. Franceries. "A numerical modelling of an electric arc and its interaction with the anode: Part II. The three-dimensional model- influence of external forces on the arc column", 2005, in J. Phys. D: Appl. Phys, vol 38, pp. 306- 318.
[11] J. Goldak, M. Bibby, J. Moore, and B. Patel, "Computer modeling of heat flow in welds", in Metall. Trans B. 1986, vol 17, pp. 587-600.
[12] A.B. Murphy, "Transport coefficients of Helium and Argon-Helium plasmas", in IEEE Transactions on plasma science, 1997, vol. 25, n┬░ 5.