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Show Prediction of the Temperature Distribution of a Slab in a Continuous Reheating Furnace Toshiaki SAITO Technical Development Bureau, Nippon Steel Corporation Sintomi 20-1, Futtsu City, Chiba, 293, Japan Abstract: A mathematical model to predict the temperature distribution of a slab in a continuous reheating furnace has been developed. A n essential feature of the model is to consider the effects of the local temperature of the skid, the walls, and gas in the furnace as individual radiant heat sources. The R E A D ( Radiative Energy Absorption Distribution) method is employed to calculate the local heat flux on the slab surface. Several numerical investigations have been performed concerning the relations between the temperature distribution of slab and the conditions of the skids and gas using the two-dimensional unsteady model. Numerical results lead to the conclusion that one of the important factors to minimize the "skid mark", is that both of the position of the skid beams and the temperature profile of gas must be optimized at the same time. 1. Introduction One of the most important subjects of a reheating furnace in industrial steel works is to heat steel slabs uniformly. Temperature of a discharged slab from the furnace is required to be enough high and enough uniform for rolling. Temperature non-uniformity of a slab causes fuel loss and deterioration in quality of the slab. Radiative heat transfer is a dominated heat transfer in the furnace. Incident heat to slabs by radiation is more than 9 5 % to the total incident heat. The skids supporting slabs are cooled by water inside, and low temperature region called "skid mark" is formed in the slab due to the reduction of the radiative heat transfer by shadow of skids and the heat losses through the water-cooled skid beams. In the conventional furnace, the contact region with the skid beams are shifted in order to reduce the "skid mark". In this study, authors have developed a two-dimensional unsteady mathematical model to predict "skid mark" accurately. The geometry of furnace and local temperature of combustion gas, surfaces of walls and surfaces of skid beams are taken into account in this model. Neither the empirical models using the "overall heat exchange factor" nor the |
