Method for enhancing the heating efficiency of continuous slab reheating furnaces
AssigneeUnited States Steel Corporation
InventorLawrence G. Seigel
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Abstract
Significant energy savings are achieved in the operation of reheat furnaces when the preheat zone temperatures are maintained as low as possible consistent with the demands of the hot strip mill. While the benefits of this invention may be realized through manual adjustment, further energy savings are achieved through the utilization of automatic controls and proper scheduling in which slabs of approximately the same thickness are placed into groupings so that a first grouping of tandum slabs enters the furnace, followed by a second grouping of different thickness.
Claims7
In the reheating of slabs to temperatures of about 1150.degree. to 1320.degree. C for further processing in a roll mill, wherein said slabs are elevated to such temperatures by passage through a continuous, co-current fired, pusher type, slab reheating furnace, comprising a preheat zone, a heat zone and a soak zone and heating means associated with each such zone, in which the soak zone is maintained at a median temperature approximately that of a desired exit slab temperature, and the heat zone is maintained at a temperature below that at which the surface of the slabs would melt to a significant extent, but at least that required to impart sufficient heat to achieve said desired exit slab temperature, and wherein the slabs on exiting said furnace are thereafter hot-rolled to semi-finished products,
- the improvement for enhancing the heating efficiency of said furnace which comprises,
- (a) maintaining said preheat zone at a median temperature, T.sub.p, (i) at least that required to provide a heat-rate sufficient to achieve said desired exit slab temperature, but (ii) no greater than 90% of said soak zone median temperature, T.sub.s ;
- wherein T.sub.p and T.sub.s are measured in .degree. C.
Dependencies are inferred from the claim text.