A technique used with the shielded metal arc welding (SMAW) process in which heavily coated iron powder electrodes are dragged in the joint. The core rod of these electrodes becomes recessed in the coating during welding, forming a relatively deep cone. Since the coating is a poor conductor, it can be in contact the weld pool without shorting the arc.
The contact arc welding technique permits automatic maintenance of the arc, and results in the following advantages: easily started arc, constant arc length, improved welds, and reduction of welder fatigue.
Contact arc welding was developed by Dr. van der Willigen of Holland in 1944. Among the classifications of electrodes developed to take advantage of this procedure are E7014, E7024 and E7027.