The status of twin-roll casting technology

Within the coming days the world's first commercial, direct twin-roll caster for carbon steel strip less than 2.0 mm, without further hot or cold rolling, will be started by Nucor in the United States. Although the process has been previously proven on a technical basis during full-scale development in Australia, the Nucor caster is unique in that it will have to demonstrate both its technical and economic advantages in a rigorous commercial environment. The advent of any new technology naturally raises the question of whether there is a need for that technology, and where the new technology will fit into the spectrum of existing processes. Experience to date indicates that twin-roll casters will quickly fill a latent demand for ultra-thin cast strip (UCS), i.e., a new product category for sheet steel. In the future, thick slab casters, thin slab casters and twin-roll casters will coexist and become increasingly specialized. The result will be both new and better products for steel consumers and satisfactory financial returns for steelmakers. The CASTRIP(R) process produces steel strip between 0.7 and 2.0 mm in thickness, directly from liquid steel. For many applications the UCS product will be directly usable by end users, without further hot rolling, pickling or cold rolling. It can be galvanized, coated with aluminum/zinc, painted and formed without further processing, and will be available in strength levels from about 250 Mpa to more than 600 Mpa-all using a single, simple chemistry. End-users will be able to buy a new product with price and properties intermediate between today's hot-rolled and cold-rolled steels. Among the unique features of the process is its much lower consumption of energy and reduced environmental emissions.