Spray and jet cooling in steel rolling

Prediction and control of roll and strip cooling are necessary in modern steel mills because they not only affect the process efficiency but also strongly influence the quality of rolled products. In this article, relationships among metallurgy, heat transfer, and control of the cooling system in steel rolling are first discussed. Heat transfer characteristics associated with the water spray and jet cooling used in rolling processes are then studied. The effects of important convective heat transfer parameters on cooling perormance for both stationary and moving surfaces are examined. Results indicate that local heat fluxes up to 20 × 10⁶ W/m² are observed in the nucleate boiling regime. The present results are compared with typical boiling heat transfer studies in terms of heat fluxes, heat transfer coefficients, spray rate, and cooling efficiency. The effect of surface motion is found to increase the cooling efficiency of roll and strip cooling. Finally, implementation of the present finding in roll and strip cooling to thermomechanical processing in steel rolling is proposed.