Electro-slag remelting

Electric current (generally AC) is passed between the electrode and the new ingot, which is formed in the bottom of a water-cooled copper mold.

The new ingot is covered in an engineered slag that is superheated by the electric current.

[2] Electroslag remelting uses highly reactive slags (calcium fluoride, lime, alumina, or other oxides are usually the main components) to reduce the amount of type-A sulfide present in biometal alloys.

ESR reduces other types of inclusions as well, and is seen as an alternative to the vacuum arc remelting (VAR) method that is prevalent in US industries.

An example of the use of the electro-slag refined (ESR) steel technique is the L30 tank gun.