**Min-Seok Kim 1,\*, Hyoung-Wook Kim 1, Su-Hyeon Kim <sup>1</sup> and Shinji Kumai <sup>2</sup>**


Received: 3 May 2019; Accepted: 1 June 2019; Published: 3 June 2019

**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.

**Keywords:** high-speed twin-roll casting; roll separating force; Al-Si alloy; Al-Mg alloy
