STRIP CASTING

Start up method for initiating casting of metal strip in a twin roll caster comprising parallel casting rolls (16). A casting pool of molten metal is supported on the casting rolls and confined at the ends of the rolls by side closure plates (56) and the rolls are rotated to deliver cast strip downward ly from the nip between them. One roll (16) is continuously biased laterally toward the other roll (16) either by spring biasing units (110) or by hydraulic biasing units (11). On start up the gap between rolls (16) is set so as to be less than the thickness of the strip to be cast and the rolls are rotated at such speed that on pouring of molten metal to initiate casting strip is produced to a thickness which is greater than the initial gap betwe en the rolls thereby to cause the biased roll (16) to move bodily away from the other roll to increase the gap between the rolls to accommodate the thicknes s of the cast strip. This allows initiation of casting without the need for introduction of a dummy bar between the rolls. The peripheral surfaces of rolls (16) may have a negative crown c and the initial gap at the centres of the rolls may be d0=2c + g0 where g0 is an initial roll edge gap.