Investigation into Cr(VI) generation in metal inert gas (MIG), metal active gas (MAG), and flux cored arc welding (FCAW) by varying the oxidation potential of the shielding gas

The presence of Cr(VI) in welding fumes classifies them as carcinogens, posing a health risk to welders. Therefore, it is crucial to minimize welders’ exposure to Cr(VI) by understanding the role of shielding gases in the generation of Cr(VI) during welding. This article offers valuable insights into the impact of shielding gases’ oxygen index on Cr(VI) production in welding fumes and highlights key variables that influence the Cr(VI) generation during welding. The study reveals that the behavior of shielding gases in Cr(VI) production varies between flux-cored arc welding (FCAW) and solid stainless-steel wires, with the oxidation index of the shielding gas playing a significant role in solid stainless-steel wires. Furthermore, the study indicates that the arc stability and ionization potential of shielding gases also affect the amount of Cr(VI) produced. Interestingly, the use of a CO2 and O2 mixture with Ar resulted in the lowest formation of Cr(VI). In FCAW, the highest levels of Cr(VI) were observed when argon was used as the shielding gas, primarily due to the presence of Na and K in the wires, which promote the oxidation of Cr(III) to Cr(VI). Conversely, the utilization of oxidizing shielding gases reduces the formation of Cr(VI) as Na and K react with oxygen to form their oxides, thereby reducing the availability of these elements to form chromates and dichromates.