Steel
Fume will be produced during welding and cutting of carbon and alloy steels. Fume comprises particulate fume, which you can see, and gaseous fume, which is not visible. What is in the fume and how much of it there is depends on the steel, the consumables, fluxes or gases being used, and the process being used to weld or cut the steel. Particulate fume from mild and low carbon steels tends to be comprised of iron oxide plus some manganese oxide, and possibly barium, from some self-shielded wires, and inorganic fluorides, from basic MMA electrodes. Alloy steels also contain oxides of whichever alloying elements are present. If gaseous fume is produced the most important component is ozone, a reactive, toxic, gas. The processes tending to give most fume are cored wires, MMA, and MIG welding, and plasma cutting. Those giving the least are TIG and submerged arc welding and gas cutting. At high currents the open arc processes MIG, TIG, and cored wire welding can generate ozone at high current when using argon-rich gases. Welding with CO2 gas does not produce ozone. In general terms, as process current increases so does fume production. Particulate fume from welding and cutting steel is not thought to present any major hazards. Alloying constituents, manganese, nickel, and chromium only tend to be produced in low concentration. If ozone is generated then precautions must be taken to keep exposure to a minimum.
|
