Experimental investigation of the effect of hydrogen in argon as a shielding gas on TIG welding of austenitic stainless steel

Tungsten?inert-gas welding arcs are modelled using a two-dimensional axisymmetric computational code. Both electrodes (the tungsten cathode and the metal anode workpiece) and the arc plasma are included self-consistently in the computational domain. The influence of adding helium, hydrogen and nitrogen to the argon shielding gas is investigated. It is found that addition of any of the gases increases the heat flow to and the current density at the anode. The shear stress and the arc pressure at the anode surface are increased by adding hydrogen or nitrogen or up to about 50?mol% helium, but decrease when more helium is added. It is predicted that the effect of adding any of the gases is to increase the depth of the weld pool, in agreement with the experimental evidence. The results are explained by referring to the thermodynamic and transport properties of the gas mixtures.

https://iopscience.iop.org/article/10.1088/0022-3727/42/11/115205/pdf

A computational investigation of the effectiveness of different shielding gas mixtures for arc welding

Experimental research of the effect of hydrogen in argon as a shielding gas in arc welding of high-alloy stainless steel

Emission spectrometry evaluation in arc welding monitoring system

Magnesium alloy components are frequently gas tungsten arc welded despite magnesium's high thermal diffusivity. Gases such as argon, helium, -and nitrogen - enriched or not with hydrogen - have been investigated to determine if melting, and in particular weld penetration, can be increased. Images of the arcs, voltage readings, dimensions, defects, and microstructure of weld fusion zones have been examined. Due to a greater first ionization potential, helium increased the constant-current voltage and created more melting than argon. With diatomic gases such as nitrogen and hydrogen, voltage and weld dimensions were even further increased. However, hydrogen caused porosity, and nitrogen interacted with magnesium by leaving a nitride deposit at weld surfaces. While consequences of alloying with nitrogen were probably not disadvantageous, hydrogen pores were of greater concern. Both welding parameters and hydrogen concentration in the arc atmosphere were important in controlling porosity. The two-dimensional heat-flow conditions of fully penetrating welds were capable of eliminating porosity and could make welding with hydrogen additions a possibility to consider.

An investigation on the effects of gases in GTA welding of a wrought AZ80 magnesium alloy

The influence of hydrogen additions to an argon shielding gas on the heat input and weld bead morphology was investigated using the gas tungsten arc welding process. Variations in weld bead size and shape with hydrogen additions were related to changes in the ability of the arc to generate heat and not to generate perturbations in the weld pool caused by Marangoni fluid flow

S. Liu

Papers

Effect of hydrogen in an argon GTAW shielding gas: Arc characteristics and bead morphology