Role of Roll Separating Force in High-Speed Twin-Roll Casting of Aluminum Alloys

Min-Seok Kim,Su-Hyeon Kim,Shinji Kumai,Hyoung-Wook Kim

doi:10.3390/met9060645

Min-Seok Kim, Su-Hyeon Kim + Show 2 more

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https://doi.org/10.3390/met9060645

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Abstract

The role of the roll separating force in the high-speed twin-roll casting of aluminum alloys was examined. In horizontal-type twin-roll casting, as the casting speed increased upon decreasing the roll separating force, the strip texture changed from a shear and rolling texture to a random texture. Direct temperature measurements during high-speed twin-roll casting showed that the roll separating force played a significant role in maintaining a good contact between the strip and the roll surface. This resulted in a high cooling rate around the roll nip and enabled the fabrication of a sound strip with a fine microstructure. Moreover, the high casting speed and lowered roll separating force gave a band structure consisting of fine globular grains in the mid-thickness region of the strip, which could be considered beneficial in the formation of a well-dispersed center segregation.

Highlights

In aluminum sheet production, the twin-roll casting (TRC) process has attracted increasing attention due to its economic advantages when compared with conventional direct-chill slab casting and hot rolling processes
To maximize the cooling rate and raise the casting speed in the horizontal-type TRC process, Cu-Cr rolls were used and the castings were conducted in the absence of lubrication on the roll surface
Upon increasing the casting speed with a reduced roll separating force (RSF), it was found that the strip texture changed from a rolling texture to a random texture

Summary

Introduction

The twin-roll casting (TRC) process has attracted increasing attention due to its economic advantages when compared with conventional direct-chill slab casting and hot rolling processes. The traditional TRC process was designed to combine the metal casting and hot rolling processes into a single operation, and in general mass production, a horizontal-type (or slightly tilted) caster is typically employed, where the casting speed is optimized to give a range of

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