Heat transfer model for skidmark formation on slab in a reheating furnace

A heat transfer model is developed as a furnace-design aid to predict skidmark formation on a steel slab in a reheating furnace. Quasi-steady two-dimensional heat transfer transverse to the marching direction of the slab in the furnace is considered. By taking account of the heat exchange between the slab and its surroundings in the furnace, including radiant heat transfer among the slab, the skids, the hot gases and the furnace walls; conduction interaction between the slab and the skids; and the gas convection heat transfer in the furnace, the model can predict the temperature distributions in the slab and the skids throughout the reheating process. At the exit of the soaking zone of the furnace, the extent of the skidmark formed on the slab can then be evaluated quantitatively based on the predicted temperature distribution. A comparison is made between the predictions of the present model and the data from an in situ measurement in the furnace, and a reasonable agreement is found. The results of the present simulation further demonstrate that the dominant contributor to the skidmark formation on the slab in the reheating furnace modelled is the shielding effects due to the skid structure. Moreover, the skidmark is found to be strongly affected by the slab marching speed.