In gas metal arc welding (GMAW), a consumable electrode wire is fed normally at a pre-determined constant speed in order to achieve a stable welding process for given welding conditions. In this article, a comprehensive mathematical model for GMAW was employed to study the interplay among electrode melting; the formation, detachment, and transfer of droplets; and the plasma arc under various welding conditions. It is found that a stable GMAW process can be obtained through a balance between the wirefeed- speed (WFS) and the dynamic electrode melting rate due to the transient behavior of plasma arc. Otherwise, an unstable welding process including electrode burned-back or stick-onto the weld pool could occur. The model-predicted equilibrium WFS varying with welding current and feeding-wire diameter is in good agreement with the published empirical results obtained through a trial-and-error procedure. © 2012 Elsevier Ltd. All rights reserved.
- Electrode Melting,
- GMAW,
- Plasma Arc,
- Wire-Feed-Speed
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