Report on Welding Metallurgy of Girth Weld Defects in Mechanised GMA Field-Welded Pipe Lines

The terms semi-automatic arc welding and fully automatic arc welding are wel-known, yet they need to be cleanly demarcated. In semi-automatic welding the wire feeder maintains the arc and feeds the wire, the operator's job is to manipulate the arc along the joint. In fully automatic welding all the welding parameters are oresent and the entire operation from start to finish is accomplished by the equipment. The operator's role is nill.