Abstract:A dynamic secondary water cooling control system, Visual Cast, has been developed by using the incremental PID control algorithm and the transient heat transfer model in which the heat transfer along the casting direction was taken into account. The slab surface aim temperatures were determined according to the hot ductility of the steel measured by the Gleeble tensile experiment. Compared with the traditional water table method, Visual Cast control system showed higher capability and sensibility in adjustmen of cooling water flowrate to maintain the slab surface temperature when casting speed was changed and it was qualified to be used in the practical production of steel slab.