When the welding process begins, an arc is created between the electrode and the workpiece. When the welding flux that is put in the joint melts, a slag pool is produced and it then increases in depth. When the temperature of the slag and its conductive capacity thereby increases, the arc is extinguished and the welding current is conducted via the molten slag, where the necessary welding energy is produced through resistance.



The weld is formed between fixed, water-cooled copper shoes or moving shoes and the joint faces. The welding head moves upwards as the welding proceeds. One or more electrodes are used as the consumable, depending on the plate thickness. If the base material is very thick, electrode oscillation may be used.
The advantages of this method include:
* High productivity
* Low joint-preparation cost
* The fact that it can be performed as a single pass, regardless of plate thickness
* No angular deformation with butt joints
* Little transverse stress
* Low risk of hydrogen cracking

The weakness of the method is the fact that the large amount of energy used helps to produce slow cooling, which results in powerful grain growth in the heat affected zone (HAZ). The notch toughness of the base material in the HAZ is not sufficiently high to comply with the requirements imposed on welded structures with guaranteed protection from cracking at low temperatures, otherwise known as protection from brittle fracture.