A model for heat conduction through the oxide layer of steel during hot rolling

摘要

A heat conduction model developed to predict the temperature distribution within the oxide layer of carbon steel being rolled is presented. This model takes into account the different physical properties of the three oxide species, and the parabolic growth of the layer. The thickness of the layer is divided into 40 nodes or elements of which 36 are considered to be of wustite, three of magnetite and only one of hematite to comply with their proportions. It is found that this particular model is too complicated when the aim is to evaluate the effect of the oxide crust in thin oxide layers, such as those encountered during strip rolling, because similar results can be obtained using a single node model based on the properties of wustite; whereas with the behaviour of thick layers, such as those encountered after reheating or during roughing passes, is modelled, the present model becomes valuable. The thermal gradients predicted by the model can be employed to predict the integrity of the oxide layer.