Electroslag Refining

Electroslag Remelting



The Electroslag Remelting (ESR) Process has been developed
and introduced as a production process for high grade steel ingots
in 1958 in the Soviet Union, and is being applied in Western
Europe since 1966. In the 1960‘s, independend research in the
field of ESR has been done in Austria and Great Britain. At the
same time, the first ESR-plants have been installed in Western
Europe and the US on an industrial scale basis.
Since then the production capacity for ESR-steel has reached
more than 1,200,000 tons per year. Although secondary liquid
metal refining processes have been able to replace the ESRprocess
to some extent for a variety of products, the ESR-process
is still gaining increasing importance when control of solidification
in regard to macro- and microstructure as well as higher
cleanliness levels are required.
Another considerable advantage of ESR compared to conventional
ingot casting is the increased yield, which gains importance
with an increasing ingot diameter.
In Electro Slag Remelting, a new remelted ingot is formed in a
water cooled copper mold by remelting a consumable electrode
in a superheated slag bath. The heat required to melt the electrode
is produced when current passes through the liquid slag
by its electrical resistance. The melting rate of the consumable
electrode is controlled by the power input to the slag pool.
By choosing suitable conditions the depth and shape of the liquid
metal pool can be controlled as such that homogeneous
and segregation free ingots are obtained. The liquid metal droplets
formed at the tip of the electrode pass through the superheated,
metalurgically active liquid slag, thereby creating excellent
conditions for slag-metal reactions, such as removal of sulphur
and oxygen.