Heat transfer analysis and experimental study of unequal diameter twin-roll casting process for fabricating Cu/Al clad strips

Unequal diameter twin-roll casting (UDTRC) can improve the formability, surface conditions, and production efficiency during the fabrication of clad strips. Using Fluent software, a numerical simulation is used to study the asymmetric heat transfer characteristics of Cu/Al clad strips fabricated by UDTRC. The effects of roller velocity ratio, Cu strip thickness, and inclination angle on the kissing point position, as well as the entire temperature distribution are obtained. The heat transfer model is established, and the mechanism is discussed. The Cu strip and rollers are found to be the main causes of asymmetric heat transfer, indicating that the roller velocity ratio changes the liquid zone proportion in the molten pool. The Cu strip thickness determines the heat absorption capacity and the variations in thermal resistance between the molten Al and the big roller. The inclination angle of the small roller changes the cooling time of big roller to molten Al. Moreover, the microstructure of Al cladding under different roller velocity ratios is examined. The results show significant grain refinement caused by the shear strain along the thickness direction of Al cladding and the intense heat transfer at the moment of contact between the metal Al cladding and Cu strip.