There are two main casting processes used in the production of steel ingots and billets: die casting and continuous casting. Each process has its own advantages and limitations. Although continuous casting plays a dominant role in modern steel production, die casting remains irreplaceable in certain applications.
In the die casting process, a batch of molten steel is poured intermittently into multiple molds to form individual ingots. After solidification and cooling, the mold is removed to obtain the finished ingot. Die-cast steel typically features a dense structure and superior mechanical properties. The distribution of alumina inclusions and carbides is more uniform than in continuous cast materials, resulting in higher contact fatigue life.
However, die casting is less suitable for high productivity operations. Some steel grades are not compatible with continuous casting techniques, and large-scale components—such as hydropower turbine rotors or the main shafts of super-large ships—are commonly produced via die casting.
The continuous casting process involves the steady flow of molten steel into a tundish, from which it is distributed into a mold. There, the steel is rapidly cooled and solidified into billets or slabs, which are used as semifinished products for rolling mills. This method is capable of producing over 500 types of steel, including ultra-pure steels, high-grade silicon steel, stainless steel, Z-direction (lamellar tearing-resistant) steel, pipeline steel, and heavy rail steel.
Compared with die casting, the continuous casting process requires fewer production steps, reduces plant floor space by approximately 30%, and lowers operational costs by about 40%. It also decreases refractory material consumption by 15%. Cutting loss from billet head and tail is minimized, and the overall metal yield improves by around 9%. Furthermore, the process is highly automated, significantly reducing labor intensity for workers.
