Title

Study the Shielding Gas Effects on Transport Phenomena in GMAW Arc

Abstract

This article presents a numerical investigation on the transient transport phenomena including the arc plasma generation and evolution; droplet formation, detachment, transfer and impingement onto the workpiece; weld pool dynamics and final weld bead shape for pure argon and three argon-helium mixtures (75% Ar + 25% He, 50% Ar + 50% He, and 25% Ar + 75% He) during the GMAW process. The results indicate that the arcs in different shielding gases behave very differently due to the significant differences in thermophysical properties, including the ionization potential and the electrical conductivity, thermal conductivity, specific heat, and viscosity at high temperatures. For the same welding power input, the increase of helium content in the mixture leads to a stronger convergence of electric current at the workpiece and a stronger upward electromagnetic force near the workpiece, resulting in a cone-like plasma arc, which is in contrast to a bell-like plasma arc for argon-rich mixtures.

Meeting Name

20th International Symposium on Transport Phenomena

Department(s)

Mechanical and Aerospace Engineering

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 20th International Symposium on Transport Phenomena, All rights reserved.

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