Numerical Investigations of the Influence of Metal Vapour in GMA Welding
- 277 Downloads
Current numerical models of gas metal arc welding (GMAW) attempt to combine a magnetohydrodynamic (MHD) model of the arc and a volume-of-fluid (VoF) model of metal transfer. But in these models vaporization of metal is neglected and the arc region is assumed to be composed of pure argon, as it is common practice for models of gas tungsten arc welding (GTAW). These models predict temperatures over 20 000 K and a temperature distribution similar to GTAW arcs. However, recent spectroscopic temperature measurements in GMAW arcs have demonstrated much lower arc temperatures. In contrast to GTAW arcs, they found a central local minimum of the radial temperature distribution. The paper presents a GMAW arc model that considers metal vapour and which is in very good agreement with experimentally observed temperatures. Furthermore, the model is able to predict the local central minimum in the radial temperature and the radial electric current density distributions for the first time. The axially symmetric model of the welding torch, the workpiece, the wire and the arc (fluid domain) implements MHD as well as turbulent mixing and thermal demixing of metal vapour in argon. The mass fraction of iron vapour obtained from the simulation shows an accumulation in the arc core and another accumulation on the fringes of the arc at 2 000 to 5 000 K. The demixing effects lead to very low concentrations of iron between these two regions. Sensitive analyses demonstrate the influence of the transport and radiation properties of metal vapour, the welding current and the evaporation rate.
IIW-Thesaurus keywordsArgon Diffusion Evaporation GMA welding Plasma Radiation Simulating
Unable to display preview. Download preview PDF.
- Radaj D.: Schweißprozesssimulation: Grundlagen und Anwendung — Simulation of welding processes: fundamentals and applications, Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, Düsseldorf, 1999 (in German).Google Scholar
- Hu J. and Tsai H.L.: Heat and mass transfer in gas metal arc welding, Part I: The arc, International Journal of Heat and Mass Transfer, 2007, vol. 50, no. 5-6, pp. 802–820.Google Scholar
- Spille-Kohoff A.: Numerische Simulation des ChopArc-Schweißprozesses — Numerical simulation of ChopArc-welding process, Final Report ChopArc, Fraunhofer IRB Verlag, 2005 (in German).Google Scholar
- Metzke E. and Schöpp H.: Spektralanalyse Metall-Lichtbogenplasma, Optical spectral analyses of arc plasmas within metal vapour, Final Report ChopArc, Frauenhofer IRB Verlag, 2005 (in German).Google Scholar
- Goecke S.F.: Auswirkungen von Aktivgaszumischungen im vpm-Bereich zu Argon auf das MIG-Impulsschweißen von Aluminium, Active gas additions in range of vpm in argon and their influence on pulsed MIG-welding of aluminium, PhD Thesis, TU Berlin, 2004 (in German).Google Scholar
- Briand F., Zielińska S., Musiol K., Pellerin N., Pellerin S., de Izarra Ch., Richard F. and Opderbecke T.: Experimental investigations of the arc in MIG-MAG welding, IIW Doc. SG 212-1123-08, 2008.Google Scholar
- Yamamoto K., Tanaka M., Tashiro S., Nakata K., Yamamoto E., Yamazaki K., Suzuki K., Murphy A.B. and Lowke J.J.: Numerical simulation of diffusion of multiple metal vapours in a TIG arc plasma for welding of stainless steel, Doc. IIW-1963, Welding in the World, 2009, vol. 53, no. 7/8, pp. R166–R170.CrossRefGoogle Scholar
- Hertel M., Schnick M., Füssel U., Gorchakow S. and Uhrlandt D.: Numerical simulation of GMAW processes including effects of metal vapour and sheath mechanisms at the electrodes. Magnetohydrodynamics, 2010, vol. 46, no. 4, pp. 363–370.Google Scholar
- Rose S., Schnick M., Hertel M., Zschetzsche J. and Füssel U.: Transient simulation of gas metal arc welding (GMAW) processes and experimental validation, Magnetohydrodynamics, 2010, vol. 46, no. 4, pp. 403–412.Google Scholar