An analysis of heat transfer and fume production in gas metal arc welding. III

Abstract

Articles you may be interested inHeat and fluid flow in complex joints during gas metal arc welding-Part II: Application to fillet welding of mild steel J. Appl. Phys. 95, 5220 (2004); 10.1063/1.1699486 Heat and fluid flow in complex joints during gas metal arc welding-Part I: Numerical model of fillet welding J. Appl. Phys. 95, 5210 (2004); 10.1063/1.1699485 Modeling of temperature field and solidified surface profile during gas-metal arc fillet welding J. Appl. Phys. 94, 2667 (2003); 10.1063/1.1592012Modeling of heat transfer and fluid flow during gas tungsten arc spot welding of low carbon steel A theoretical model for gas metal arc welding and gas tungsten arc welding. I.A two-dimensional dynamic theory for predictions of arc and electrode properties in arc welding has been used to investigate heat transfer phenomena in the welding wire in gas metal arc welding ͑GMAW͒. The theory is a unified treatment of the welding wire, the plasma and the workpiece and includes a free surface treatment for the welding drops, accounting for the effects of inertia, gravity, surface tension, arc pressure, magnetic forces, and viscous drag by the gas flow around the drop. Also, the theory accounts for the variation of the surface tension coefficient with temperature and includes thermal and dynamic phenomena within the solid and liquid phases of the wire, together with a detailed treatment for the electrode sheath regions. Calculations are made for arcs in argon with wires of mild steel at currents between 150 and 325 A. Results of calculations for heat fluxes within the wire suggest that evaporation from the surface of the droplet during droplet growth has an important influence on the heat balance of the wire. The calculated evaporation rates from the droplet surface during droplet growth at the tip of the wire are found to be much higher than measured rates of fume formation in GMAW, suggesting an important recondensation process at the surface of the workpiece.

Arc Welding Health Effects, Fume Formation Mechanisms, and Characterization Methods

“…Particles form when the metal vapor condenses. About 1% of the electrode condenses into metal oxide nanoparticles which aggregate together to form particle agglomerates (Haider, 1999). Welding fume can be present in different morphologies.…”

Wpływ oparów metalicznych na spawanie łukowe, część 2: Obliczanie

“…Ten przepływ jest szczególnie silny blisko elektrody w łukach spawalniczych GMAW. Ponadto, kwestią sporną jest również, czy szybkość odparowywania zmniejsza się poniżej poziomu danego wzorem (23) [165]. Jeśli tak jest, to zmniejszy się także chłodzenie związane z odparowywaniem kropli powstających na elektrodzie.…”

Synthesis of Al Nanopowders in an Anodic Arc

“…Reference [8]). Heat transfer from the plasma to the anode is mostly due to the combined effects of condensation of electrons carrying the arc current and conduction from the plasma [14,15].…”