Experimental Study on the Characteristics and High-Temperature Heat Transfer of Secondary Cooling Nozzle for High-Efficiency Slab Continuous Casting Process

In the continuous casting process, the heat transfer effect of secondary cooling plays an important role in the quality of the slab. The cooling intensity and cooling uniformity of the secondary cooling nozzle need more efficient spray cooling to achieve. Herein, the cold characteristics of different types of nozzles were compared. It is found that the second type of air mist nozzles have more uniform water density and striking force. On this basis, high-temperature heat transfer experiments for casting billets were carried out to study the heat transfer coefficients of different air mist nozzles in the secondary cooling zone of continuous casting. It is found that the heat transfer coefficient increases as the distance of the temperature measurement point from the nozzle directly below increases. The heat transfer coefficients of the casting billet in both the jet and non-jet zones are decreasing to varying degrees. When the temperature drops to 600 °C, the second type of air mist nozzle shows a faster temperature drop at the point of measurement, a smaller difference in time taken for temperature drop between jet and non-jet zones, and faster and more uniform spraying, leading to a more significant trend of increasing heat transfer coefficient.