Determination of effective heat transfer coefficient for water spray cooling of steel

Accurate control of the temperature of the workpiece is crucial when carrying out thermal processing of steel. Effective heat transfer coefficient for water cooling of hot rolled steel was calibrated using spray nozzles with different amounts of water flux. Austenitic stainless steel was chosen for the studies in order to avoid the release of latent heat, which would affect the result in the case of carbon steels. Three different measurement sites acquired with thermocouples were used, namely in the middle and at the quarter distance from both top and bottom surfaces. The heat transfer coefficient was fitted to the experimental data using a computational model, which calculated the time-dependent temperature distribution within the steel slab. The model was validated by altering the experimental exposure time to the water spray and compared the model prediction to the observed result. The calibrated model provides the capability to design and carry out cooling routes in thermomechanical processing of steel in practice.