Modelling of temperature-dependent growth kinetics of oxide scale on hot-rolled steel strip

A numerical simulation, developed to predict the temperature distribution and calculate the growth rale of the

oxide scale formed on the microalloyed low carbon steel during the laminar cooling of hot strip rolling, was

conducted by two-dimensional finite element method. The model takes into account the different thetmoPhYsical

properties of the multilayered oxide scales and the film boundary conditions for the water jet impingement zone

and the stable film boiling zone through the run-out table. Complied with the parabolic growth of the oxide

layers and the distribution of the oxide phase, it is found that the present of wustite (FeO) results in a significant

increase of the oxidalion rate. However. the parabolic rate constant for the simultaneous growth of the two ouler

layers of magnetite (FelO,) and hemaUle (FelOJ) reduce rapidly compared to thai of three-layer oxide scale.

The growth rates and temperature gradients predicted by the model can be employed to elucidate the formation

mechanism of oxide scales, as well as to analyse oxide scale failure.