Metal Vapour Effect in an Argon TIG Welding Plasma
Dr Junting Xiang
CSIRO Manufacturing, Australia
Time & Place
Fri, 20 Sep 2019 15:00:00 NZST in E14, Engineering CORE
In the present work, we investigate metal vapour diffusion in an argon arc with a stainless-steel workpiece and assess how each diffusion driving force affects the overall transport of metal vapour in the TIG process. An axisymmetric computational model incorporating the arc and the weld pool is applied to treat the transport of iron and chromium vapour in the argon arc plasma, using the combined diffusion coefficient method (Murphy 2014), which takes into account ordinary diffusion, temperature diffusion, pressure diffusion and electric field diffusion at the same time. The results show that in an argon arc, electric field diffusion is weaker than in a helium arc, and diffusion due to the temperature gradient dominates metal vapour transport. The effect of ordinary diffusion is also significant, especially in the region close to the weld pool. When all the diffusion effects are included, the arc temperature is predicted to be significantly reduced due to the enhanced radiative cooling associated with the presence of the metal vapour. The results demonstrate that metal vapour effect in an argon arc is significant and the transport mechanism of metal vapours in an argon arc plasma are discussed.
Dr. Junting Xiang is currently a research fellow in CSIRO Manufacturing, Australia. He obtained PhD from Nanyang Technological University in Singapore and he was pivotal to the success of several government and industry funded projects including design of miniature gas turbine engine, particle-laden flow simulation and high-temperature metal processing. Dr. Xiang has research interest in thermo-fluid mechanics, mathematical modelling, multi-physics calculation and additive manufacturing.