Horizontal Single Belt Casting of Aluminum Sheet Alloys

Recent work on the casting of thin, wider sheets of aluminum alloys on the Horizontal Single Belt Caster (HSBC), has once again confirmed the viability of this casting process to deliver liquid metal of thicknesses ~5 mm, or less, onto a moving water cooled belt, in an iso-kinetic manner. For this, the speed of the liquid metal delivered across the width of the belt, must quickly match that of the water-cooled moving belt, whilst avoiding potential backflows and hydraulic jumps. The caster, now operating at MetSim Inc. is producing strip widths up to ~250 mm. As for the 100 mm wide strips cast in the past, the newer samples produced were improved in terms of uniform cross-sectional thickness, possessing good, top and bottom, quality surfaces, with straight edges. Compared with yields of ~65% for Direct Cast (DC) sheet material, for this HSBC sheet yields approach ~100%, without any need for side dams, or electromagnetic braking. The success of the present system relies on sophisticated metal flow management, in the presence of relatively rapid, unconstrained, solidification. This results in uniform, fine-grained, microstructures of aluminum alloys, free of any macro-segregation, macro-porosity, or surface blemishes, with equivalent metallurgical properties to those of the DC cast material. As such, downstream processing steps to final product are significantly reduced, with attendant cost savings, whilst capital costs for a full-scale system are relatively inconsequential, versus equivalent DC costs.