Study on high-speed twin-roll caster for aluminum alloys

A novel vertical twin-roll caster called hydrostatic press twin-roll caster (HPTRC) is presented for the strip casting of aluminum alloy. The caster employs copper rolls with high cooling capacity and a configuration with easily adjustable melt-roll contact length. The low separating force of the copper rolls eliminates the need for lubrication, and coupled with the hydrostatic pressure of the melt head, improves the contact between the melt and the rolls to significantly increase the cooling rate. The proposed system is unaffected by agitation of the melt surface, and the casting conditions are maintained constant. The technique is demonstrated to cast aluminum alloys with both wide and narrow freezing zones at speeds of 90–150 m/min with superior surface and microstructural properties and similar mechanical properties compared to conventional techniques. Strips of 1.2–2 mm in thickness can be cast directly by this method with lateral variation of less than 0.1 mm, and the strips can be subsequently cold-rolled to as thin as 0.5 mm without annealing. Cold-rolling at 20% reduction is sufficient to provide a strip of uniform thickness.