IMPROVING THE EFFICIENCY OF BELL-TYPE FURNACES AND THE QUALITY OF ANNEALED ROLLED PRODUCTS

摘要

It is known that the thermal regime of the furnaces used for the recrystallization annealing of cold-rolled products depends on the type of lining used for the covers of these furnaces. For example, the thermal conductivity of the fibrous insulating materials used by the companies Ebner and LOI is considerably (by an order of magnitude) lower [1,2] than that of the lightweight (fireclay) brick which has traditionally been used. This was confirmed by the results of commercial trials conducted in cold-rolled products shop No. 1 (CPS-1) at Zaporozhstal': the surface temperature of the frame of a cover lined with a fibrous material did not exceed 75 deg C for the entire annealing period, while it was within the range 125-135 deg C when a brick lining was used. It was also determined that the effectiveness of using the new insulating materials depends appreciably on the external factors that determine the heat-engineering characteristics of the single-stack gas-fired furnaces used to annealing cold-rolled products: the design of the stands; the condition of the burners and the burner zone; gas pressure; volume of air injected; condition of the flue channel; the possibility of exhausting the combustion products, etc.