Twin-roll casting with an electromagnetic edge dam

Twin-roll casting is an old process that was first proposed by Bessemer. Over the years one of the main problems preventing its development has been edge containment of the liquid metal pool between the rolls. Ceramic dams pressed up against the rolls have been used with some success. However, ceramic dams have the problems of requiring a super heat to prevent solidification, ceramic wearing, high cost of ceramic replacement, and finning. The electromagnetic edge dam, with an alternating horizontal magnetic field, alleviates all these problems. However, the electromagnetic edge dam, operating at relatively high frequency, has its own problems that now appear solvable with careful design of the caster and the dam. It is the purpose of this paper to present some of the solutions that have been garnered from experiments with steel and to recommend operating parameters that would be successful.