STRIP CASTING TECHNIQUES FOR STEEL

The concept of casting molten steel directly into strip can be traced to the work of Sir Henry Bessemer. A version of Bessemer's concept can be seen in state-of-the-art continuous casting techniques for large section slabs, and an extension of CC slab casting known as thin slab casting is also nearing commercial use. On the other hand, the development of a practical strip caster with thickness ranging from several hundred microns to about 10 mm is still in the research stage. This paper describes the main trends in the development of strip casting techniques in terms of both processes and material characteristics. The twin-roll caster is the main trend in Japan, while the single-roll caster forms the mainstream in the United States. The answers to a questionnaire indicated that surface quality is the most serious impediment to the realization of a practical process, followed by strip shape. To date, the merits of process integration have usually been discussed in terms of the relative energy requirements of the respective processes, i.e. in terms of energy saving. However, the additional energy reductions which can be achieved by the strip caster in place of the conventional slab CC are marginal. Instead, reductions in finishing cost are considered to be an appropriate indicator of economic benefit where the strip CC is concerned. Thus, the goal of the race in developing a commercial strip caster is to establish techniques to assure good surface quality.