Fume Generation in CO₂ Arc Welding by Solid Wire

Abstract

The effect of welding parameters and wire compositions on the fume emission rate of CO₂ arc welding by solid wire, has been examined. In addition, high-speed photographs of welding arcs have been observed to investigate fume generating phenomena.
As welding current and arc voltage are raised, the fume emission rate increases, while it drops as tipplate distance is increased. The decrease of torch angle decreases the amount of fume. Increase of the argon content in CO₂ shielding gas decreases the fume. The CO₂ flow rate has almost no effect on the fume emission rate. The mechanism of the above phenomena can be generally explained by the fume formation mechanism previously proposed.
Reduction of C and S content in the wire decreases the fume emission rate, while reduction of Mn, Si, Ti and Al content increases the rate. The influence of P content is almost none. These variation of fume generation can be mainly explained by the short circuit frequency of CO₂ arc welding, on the basis of the fact that welding fumes are mostly generated immediately after the short circuit, which is observed by high-speed photographs.