Particulate fume from carbon steel MIG welding will contain, as oxides iron, manganese, and copper, with only insignificant traces of other elements, like chromium and nickel.
Typical percentages of the above elements in fume, are as follows:
Low alloy steel MIG wires also contain small amounts of some of the following:
Work by BOC has studied the influence of different shielding gas compositions on fume composition and concentration. It was found that, in occupational hygiene terms, there was very little difference in fume composition generated with any of the Argoshield type gases or pure CO2.
The term "Fume concentration", is generally taken to mean the concentration of fume present in the breathing zone of the welder or other operative.
The welding current has a significant affect on the FFR. Tests have shown that as the current increases the amount of fume produced rises slowly at first and then at about 180 amps when a 1.2mm diameter wire is used there is a significant increase in fume production.