Influence of the substrate strip on the asymmetric heat transfer of twin-roll casting for fabricating bimetallic clad strips

摘要

A numerical simulation method was adopted to study the asymmetric heat transfer characteristics of the twin-roll casting (TRC) process for fabricating bimetallic clad strips. A 2-D thermal-flow coupled model, consisting of molten pool, substrate strip and casting rolls, was established based on the Fluent software. The TRC process of fabricating Ti/Al and Cu/Al clad strips was analyzed. The influence of the substrate strip material properties, thickness and preheating temperature on the Kissing Point (KP) height, KP migration and temperature field of the casting rolls was determined. Then, the thermal resistance network was established, and the asymmetric heat transfer mechanism was discussed. Results indicate that, besides the process parameters, the influence of the substrate strip is significant. The effect of the process parameters, such as cast-rolling velocity and casting temperature, are mainly to change the heat input of the molten pool. Similarly, the effect of the preheating temperature is mainly to change the heat input of the substrate strip. However, the effects of the substrate strip material properties and thickness are mainly to change the total thermal resistance from the molten pool to the casting roll that contacts to the substrate strip, which is the main cause of the asymmetric heat transfer.