Modeling of heat transfer during controlled cooling in hot rod rolling of carbon steels

A mathematical model is developed to predict temperature variations and austenite phase transformation kinetics in steel rods and wires during controlled cooling after hot rolling. Two-dimensional finite element analysis is employed to solve the governing heat conduction equation with non-uniform boundary conditions as it is subjected in practical cooling layout. The kinetics of austenite transformation is also determined using the cooling curves achieved from the thermal analysis together with the additivity rule. To verify the model results, temperature profiles in steel rods cooled under different conditions are measured experimentally in laboratory and also, temperature history during controlled cooling of hot rolled wire rods are recorded using infrared pyrometer. The comparison between the predicted and the experimental results shows a reasonable agreement.