of thin sheet metal but consume significant amounts of energy – particularly with reheat furnaces. These furnaces are gas fuel energy intensive, second only to blast furnaces.
The reheat furnace is located at the hot strip mill and is the process step before hot rolling. In this step, steel billets, plates or blocks are usually heated from room temperature to ~1,200 C°. At this temperature, the billet can be hot rolled and achieve the desired metallurgical, mechanical and dimensional properties of hot rolled products. Optimal operation requires the minimization of fuel consumption, while maintaining a controlled steel billet thermal soak.
From economic, production and environmental standpoints, the operation of reheating furnaces is of great importance to the steel making process. Economically, the consumption of fuel needed for reheating can represent up to 15% of the operational cost of a rolling process. With respect to productivity, a reheat furnace capacity often dictates the production rate for the rollers, which means that reheating is usually the bottleneck in achieving the maximum production volume. The furnace operation must be reliable, as any down time will cost the average sized mini mill nearly $45,000 per hour in lost product revenue.