Cathode fall voltage of TIG arcs from a non-equilibrium arc model

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Date
2014
Volume
59
Issue
1
Journal
Series Titel
Book Title
Publisher
Heidelberg : Springer
Abstract

This work presents modelling results concerning a tungsten inert gas (TIG) welding arc. The model provides a consistent description of the free burning arc, the arc attachment and the electrodes. Thermal and chemical non-equilibrium is considered in the whole arc area, and a detailed model of the cathode space-charge sheath is included. The mechanisms in the cathode pre-sheath are treated in the framework of a non-equilibrium approach which is based on a two-fluid description of electrons and heavy particles and a simplified plasma chemistry of argon. A consistent determination of the electrode fall voltages and temperature distributions is achieved. The model is applied to arcs in pure argon at currents up to 250 A, whereby welding of a workpiece made of mild steel with a fixed burner is considered. Arc voltages in the range from 12 to 17 V are obtained at 50 at 250 A, respectively. The space-charge sheath voltage is found to be about 7 V and almost independent of the current. The corresponding temperatures of the cathode tip are in the range from 3,000 K to about 3,800 K. The results obtained are in a good agreement with measurements.

Description
Keywords
Arc welding, Cathodes, Computation, Inert gases, Simulating, Temperature, Tungsten, Welding
Citation
Uhrlandt, D., Baeva, M., Pipa, A. V., Kozakov, R., & Gött, G. (2014). Cathode fall voltage of TIG arcs from a non-equilibrium arc model. 59(1). https://doi.org//10.1007/s40194-014-0188-x
License
CC BY 3.0 Unported