Electroslag remelting (ESR), also known aselectro-flux remelting, is a process of remelting andrefiningsteel and otheralloys formission-critical applications inaircraft,thermal power stations,nuclear power plants,military technology and others.[1]
The electroslag remelting (ESR) process is used to remelt and refine steels and various super-alloys, resulting in high-quality ingots. This process can be started up throughvacuum induction melting. The ESR process uses the as-cast alloy as a consumable electrode. 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. The electrode tip is slowly melted from contact with the slag. These metal droplets travel through the slag to the bottom of the water-cooled mold and slowly freeze as the ingot is directionally solidified upwards from the bottom of the mold. The slag pool floats above the refined alloy, continuously floating upwards as the alloy solidifies. The molten metal is cleaned of impurities that chemically react with the slag or otherwise float to the top of the molten pool as the molten droplets pass through the slag.[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-Asulfide present inbiometal alloys. It is a common practice in European industries. ESR reduces other types ofinclusions as well, and is seen as an alternative to thevacuum arc remelting (VAR) method that is prevalent in US industries.
An example of the use of the electro-slag refined (ESR) steel technique is theL30tank gun.
CrNi60WTi is astainless steel which is best formed by either electro-slag remelting or vacuum arc remelting. This alloy can be used for the construction ofnuclear power plants.[3]
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