Argon and Arcal.37 plasma characteristics in a TIG configuration

In a previous paper (Mougenot 2013 J. Phys. D: Appl. Phys. 46 135206), a 3D model based on the @Saturne software was presented in argon gas and the results compared with the literature results. This paper extends the analysis from pure argon and shows the influence of added helium on plasma and weld pool properties. The influence of vapours coming from the plasma interaction with the anode material is shown in Arcal.37 gas (composed of 30% argon and 70% helium), showing the necessity to consider their presence. The importance of the forces acting on the weld pool is illustrated and analysed. The Marangoni effect is the major force acting on the weld pool leading to plasma cooling, an increase in the width of the weld pool and a reduction in its depth. (paper)