Abstract: A mathematical model was developed to describe the process of cladding casting of 4045/3003 composite ingot. The flow field and temperature field in the casting process were simulated to investigate the effect of casting speed on flow field and temperature field， which was also compared with temperature measurements during the process of cladding casting. The results showed that proper increasing the casting speed can contribute to the compounding of two alloys， but excessive speed will make the supporting outer surface so hot and thin that the interface remelted and thus the test failured. The reasonable casting speed for a smooth cladding casting is 100mm/min. Moreover， there is a good agreement between the calculated results and the measured results. The interface microstructure shows that the bonding of two different alloys are metallurgical bonding. The simulated results can predict whether the two alloys could composite together successfully or not， which provides a scientific guidance for optimizing the process of cladding casting.

Key words: cladding casting, numerical simulation, composite interface, casting speed, metallurgical bonding