Effects of activating flux on arc phenomena in gas tungsten arc welding

Abstract

Dramatic increases in the depth of weld bead penetration have been demonstrated by welding stainless steel using the gas tungsten arc (GTA) process with activating fluxes consisting of oxides and halides. However, there is no commonly agreed mechanism for the effect of flux on the process. In order to clarify the mechanism, behaviour of the arc and weld pool in the GTA process with activating flux was observed in comparison with a conventional GTA process. A constricted anode root was found in the GTA process with activating flux, while a diffuse anode root was found in the conventional process. Furthermore, it is suggested that these anode roots are strongly related to metal vapour from the weld pool, which is also related to temperature distributions on the weld pool surface.

Influence of Welding Parameters and Shielding Gas Composition on GTA Weld Shape

“…Adding and precisely controlling the quantity of these minor elements in the weld pool in GTA welding process are critical for a satisfactory weld with deep penetration. After decades of development, several methods have been found for the addition of minor elements to the weld pool by adjusting the chemical composition of the raw material, [1][2][3][4][5][6] smearing oxide or halide fluxes on the plate surface (A-TIG) [7][8][9][10][11][12][13][14][15][16][17][18][19][20] or adding active gases to the argon shielding gas. [21][22][23][24][25] Compared with the research on A-TIG, the investigation on the effect of active gaseous addition on the weld shape is limited.…”

Effects of Oxygen Additions to Argon Shielding Gas on GTA Weld Shape

“…Minor elements can be added to the weld pool by adjusting the chemical composition to the base material, [1][2][3][4][5][6] smearing fluxes (halides or oxides) on the plate surface [7][8][9][10][11][12][13][14][15][16][17][18][19] or using active gaseous addition to the argon shielding gas. [20][21][22] The intentional or unintentional addition of a small amount of minor elements to the base material significantly changes the weld penetration.…”

Numerical Analysis for Weld Formation Using a Free-Burning Helium Arc at Atmospheric Pressure

“…3 (17) . These driving forces depend not only on the physical properties of the anode materials but also the properties of the plasma state (18) . In order to obtain an assessment of the relative significance of these four forces, we have made the calculations for the steady state under the conditions of arc current 150 A and arc gap 5 mm, and with only one of the four forces operating.…”