Heat transfer behavior of top side-pouring twin-roll casting

Abstract

The interfacial heat transfer between the casting and the substrate from liquid/solid contact to solid/solid contact with pressure was investigated using a set of equipment designed according to the characteristics of the top side-pouring twin-roll casting process. The interfacial heat transfer behavior of this process consists of 4 stages: chilling, solidification shrinkage, compression and cooling. High values of the IHTC ranging from 50,000 to 90,000W/m2°C were detected in the chilling stage, followed by a sharp decrease in solidification shrinkage stage (4000–8000W/m2°C). Due to the pressure, which modeled the effect of rolling in twin-roll casting, the IHTC bounced back to 6000–20000W/m2°C, according to different conditions. The influence of process variables such as pressure magnitude, compress speed, pouring temperature, surface roughness and alloy composition had been discussed. Because of the compress action, the influence of these variables performed in a different way, but it was concluded that the way to improve the contact conditions always accompanied with an increase in the IHTC.