2017 Volume 35 Issue 2 Pages 160s-164s
Droplet temperature for Metal Inert Gas welding process was measured by using optical pyrometry; two colors temperature measurementmethod. High speed color video camera was used to capture an image of metal droplet during transfer to base metal. As a result, the movement of an arc to cover the droplet from bottom half to the entire droplet by increase of welding current had allowed the change in droplet heating process from concentrated to uniform heating. The concentrated heating in globular transfer mode had caused a higher current density at the bottom of the droplet. The change of heating process from concentrated heating in globular mode to a rather uniform heating during transition resulted in a smaller current density and reduced the heat flux into droplet, therefore decreased the droplet temperature. The further increase in welding current led the increase of droplet temperature and produced the minimum temperature in the middle of transition mode.
