Patent ID: 6581675
Filing Date: 2003-06-24
Classification: B22D

Abstract:
Apparatus for casting molten metal into a metal strip by continuous belt casting comprising:(a) a pair of moving continuous belts formed of heat conductive material, each of the belts being mounted on pulleys, including an entry pulley and an exit pulley, so that each belt passes around the entry pulley and defines a curved surface about the entry pulley, and a substantially linear surface after the belt passes around the entry pulley, the entry pulleys being mounted one above the other so that the belts, as they pass around the entry pulleys, define a gap of fixed dimension; (b) means including a nozzle for delivering molten metal to the linear surfaces of the belts, the nozzle having a tip extending to both belts and positioned after the gap at the entry pulleys; (c) a pair of pinch rolls disposed between the entry and exit pulleys adjacent the linear surface of the belts, the pinch rolls being positioned one above the other, with the belts passing over the pinch rolls and defining a nip therebetween, said nip lying in a plane defined by the axes of the pinch rolls, the nip having a gap that is smaller than the gap at the entry pulleys so that the linear surfaces of the belts converge toward each other forming a tapered molding zone therebetween, the molding zone extending between the nozzle and the pinch roll nip so that the last point of the molten metal to freeze is near the pinch roll nip and the metal strip is substantially solidified at the pinch roll nip; (d) edge containment means for preventing flow of molten metal beyond the edge of the converging belts in the molding zone, the edge containment means operating to accommodate a progressively smaller distance between the edges of the belts that occurs as a result of the linear surfaces of the belts converging toward each other in the tapered molding zone; and (e) means associated with the pinch rolls to control the spacing therebetween so that the substantially solidified metal strip has a thickness that is greater than the nip between the pinch rolls and the nip thereby provides a compressive force on the substantially solidified cast strip effective to elongate the cast strip to minimize cracking.