The effect of flow control devices with different size and installed location on fluid flow in a thin slab conca-sting tundish at Maanshan Iron and Steel has been investigated by physical and mathematical hydraulics- simulation. The re- sults showed that as tundish hadn't flow control devices there were a short flow and a big dead zone volume; and with using the flow control devices provided by SMS

the applying result wasn't optimum due to short average residence time and bigger dead zone volume; and with using the improved optimized flow control devices

the onset response time was more than two times as long as that without using flow control devices

the average residence time increased to 301.4s from 264.0s

and the dead zone volume decreased to 15.39% from 25.54% obviously to improved the metallurgical capability.