High Speed Roll Caster for Aluminum Alloy

Abstract

Two types of high-speed twin-roll casters and a single-roll caster equipped with a scraper were proposed. One of the twin-roll casters is a vertical-type high-speed twin-roll caster, and the other twin-roll caster is an unequal-diameter twin-roll caster. The vertical-type high-speed twin-roll caster can cast strip at speeds of up to 120 m/min. The unequal-diameter twin-roll caster casts strip at speeds up to 60 m/min. The unequal-diameter twin-roll caster is superior to the vertical-type high-speed twin-roll caster at the point of conveyance of the cast strip. A single-roll caster equipped with a scraper can cast strip without center-line segregation at speeds of up to 40 m/min. The use of a copper alloy roll and the non-use of a parting material enable high-speed roll casting. Since the roll loads of these casters are smaller than 0.1 kN/mm, soft copper alloy roll can be used. The strip does not stick to the roll without the parting material because of the use of the copper alloy roll with high thermal conductivity and the small roll load. The cooling rate near the surface is higher than 2000 °C/s.

Microstructure and Indentation Properties of Single-Roll and Twin-Roll Casting of a Quasicrystal-Forming Al-Mn-Cu-Be Alloy

“…New high-speed single-and twin-roll casters allow casting speed in the range of several tens of metres per minute; casting speeds of up to 60 m min −1 are pretty frequent. The melt solidifies on the rotating copper rolls enabling rapid heat extraction, achieving cooling rates above 2000 • C/s [24]. Such cooling rates can greatly refine the microstructure and improve the mechanical properties of many standard aluminium alloys.…”

“…At the roll side, outer equiaxed zone formed, which was followed by directional grow of columnar α-Al perpendicular to the roll up to approximately 500 µm from the roll side (area SR-A). In this area, cooling rates up to 2000 • C s −1 are expected [24]. These α-Al grains grew with the cellular interface morphology [31].…”

“…More details about high-speed casting can be found in Refs. [23][24][25]28]; here, some specifics are given regarding the casting of the investigated alloy.…”

“…Nevertheless, classical twin-roll casting is relatively slow, since the casting speeds can achieve only a few m min −1 . Haga et al developed high-speed single-roll [23,24] and twin-roll casting [25]. They were able to produce wrought [26] and cast [27] aluminium alloys, as well as clad strips consisting of two or three tightly bonded layers, with casting speeds of up to 60 m min −1 [24].…”

“…Manufacturing large quantities of quasicrystal-strengthened Al alloys is one of the prerequisites to their commercial application. Therefore, the use of high-speed single-and twin-roll casting may have great potential, because it provides higher cooling rates (up to 2000 • C s −1 [24]), promoting the formation of quasicrystals in Al alloys with increased quasicrystal forming ability. Thus, this work aims to verify the viability of producing quasicrystal-strengthened Al alloy strips using high-speed single-roll and twin-roll casting.…”