The effect of scaling and emulsion delivery on heat transfer during the hot rolling of steel strips

The effect of the heating/soaking environment and the location of the delivery of the emulsion spray to the surface of the work rolls on the rolling parameters, during the hot rolling of low carbon steel strips, was examined. The strips were heated in three different environments: in air for 30 min, in air for 60 min and in nitrogen, resulting in large variations in the thickness of the primary scale. The emulsion, made by the dilution of oil in water in a ratio of 1:1000, was sprayed onto the work rolls at two different locations: near to the top of the roll and near to the entry of the strips to the roll gap. The results indicate that the emulsion delivery location and the soaking environment have only minor effects on the mill loads. The most significant effects observed were the dependence of the surface heat-transfer coefficient and the appearance of the surface of the rolled strip on the process variables.