This article presents the effects of shielding gas compositions on the transient transport phenomena, including the distributions of temperature, flow velocity, current density, and electromagnetic force in the arc and the metal, and arc pressure in gas metal arc welding of mild steel at a constant current input. The shielding gas considered includes pure argon, 75% Ar, 50% Ar, and 25% Ar with the balance of helium. It is found that the shielding gas composition has significant influences on the arc characteristics; droplet formation, detachment, transfer, and impingement onto the workpiece; and weld pool dynamics and weld bead profile. As helium increases in the shielding gas, the droplet size increases but the droplet detachment frequency decreases. For helium-rich gases, the current converges at the workpiece with a "ring" shape which produces non-Gaussian-like distributions of arc pressure and temperature along the workpiece surface. Detailed explanations to the physics of the very complex but interesting transport phenomena are given.
Z. H. Rao et al., "Effects of Shielding Gas Compositions on Arc Plasma and Metal Transfer in Gas Metal Arc Welding," Journal of Applied Physics, vol. 107, American Institute of Physics (AIP), Feb 2010.
The definitive version is available at https://doi.org/10.1063/1.3291121
Mechanical and Aerospace Engineering
International Standard Serial Number (ISSN)
Article - Journal
© 2010 American Institute of Physics (AIP), All rights reserved.
01 Feb 2010