What is Continuous Casting?
Continuous casting, also known as strand casting, is the process where a metal is heated until it liquefies. The molten metal is then allowed to solidify until it becomes a semi-finished slab that is later rolled in the finishing mill. It is used to cast metals of uninterrupted lengths. In this process, the molten metal is continuously supplied to the mold. The mold has an indeterminate length. When the molten metal is cast through a mold, it keeps traveling downward increasing in its length as time passes by.
The molten metal is continuously passed through the mold, at the same rate to match the solidifying casting. This results in the casting of long strands of metal. The whole process of continuous casting is a precisely deliberated process that can produce astounding results.
Continuous Casting Process:
- Tundish is a refractory-lined vessel. Liquid steel is usually tapped from the ladle into the tundish. The stream is shrouded as it enters from ladle to tundish.
- The metal is first liquefied and poured into a tundish, which is a container that leads to the mold that will cast the steel.
- The tundish is placed about 80-90 feet above the ground level and the whole process of casting sues
- gravity to operate.
- The tundish is constantly supplied with molten steel to keep the process going.
- The whole process is controlled to ensure there is a smooth flow of molten steel through the tundish.
- Further, the impurities and slag are filtered in tundish before they move into the mold.
- The entrance of the mold is filled with inert gases to prevent the reaction of molten steel with the gases in the environment like oxygen.
- The molten metal moves swiftly through the mold and it does not completely solidify in it.
- The entire mold is cooled with water that flows along the outer surface.
- The metal casting moves outside the mold with the help of different sets of rollers.
- While one set of rollers bend the metal cast, another set will straighten it. This helps to change the direction of flow of the steel slab from vertical to horizontal.
Continuous Casting Advantages:
- The quality of the cast product is better
- A higher extent of automation is possible
- The width of the slab can be adjusted with the downstream strip mill.
Continuous Casting Applications:
Presently steels are cast continuously into slabs for flat products and bloom and billet for structural products.
