Continuous casting is a metalworking process in which metal is cast continuously, rather than being cast in discrete molds. This process is extremely efficient and cost effective, making it popular for the production of a variety of semifinished metal shapes. Once cast, the metal can be further worked as needed.
Casting in general is a process in which hot metal is poured into a mold and allowed to solidify. The metal takes on the shape of the mold, and once cooled and released, will hold that shape. The casting process is used to make solid metal parts, and also to make ingots and blocks for further processing, with each ingot containing a precisely calibrated metal alloy which can be used for a variety of purposes.
In continuous casting, metal is melted in a furnace and poured into a tundish. The pour is accomplished through ceramic piping, and the tundish is covered to prevent oxidation of the metal. From the tundish, it is released into a mold. As the metal cools and solidifies, usually aided with water cooling systems which surround the mold, finished cast metal protrudes from the far end of the mold. Torches can be used to cut the metal off at set lengths as desired.
The rate of the casting is carefully controlled so that as the metal moves out of the mold, replacement metal is poured in. In vertical continuous casting, the metal is suspended over molds, while in horizontal casting, the furnace is next to the mold. Some vertical casting setups used curved molds, with the metal moving through the curve while it is still malleable and ending up in the straight section as it cools and hardens.
Tight controls of every step of the process ensure that the composition of the continuously cast metal remains consistent and of high quality. It should be even and stable throughout when the casting operation is performed properly.
Rounds, slabs, beams, and various cross-sections can be created with continuous casting. Continuous casting of steel is probably the most popular use of this casting technique, used to make everything from steel slabs which will be worked in a mill to the I-beams utilized in construction. Companies can formulate specialty alloys by request, although the demands of the continuous casting system mean that a customer had better plan on ordering large amounts of a specialty alloy to make the operation cost effective for the foundry.