What is Electroslag Welding? (Definition, Pros and Cons)

Electroslag welding (ESW) is a single-pass welding process for joining thick materials in a vertical or near-vertical position. This highly productive welding technique uses a filler metal and the heat generated between two materials from an arc and electrical resistance.

The heat generated by the electric arc initially melts the filler metal as well as the surfaces of the metals to be joined. The arc is then extinguished and the molten slag, which is conductive, provides heat to melt the filler metal and base metal, as well as protection from atmospheric contamination as it travels along the weld joint.