JPS5534652A - Controlling method for heating furnace - Google Patents

Abstract

PURPOSE:To reduce fuel consumption per unit product as low as possible and to keep the preciseness in the extraction temp. of steel slab, by finding suitably the slab temp. in the furnace, and by heating the slab while correcting the fuel flow according to the difference between the slab temp. and the temp. shown by the predetermined temp. rise curve. CONSTITUTION:A continuous heating furnace 1 is composed of a preheating zone 2, a heating zone 3, and a soaking zone 4, and is equipped with a charged slab detector 5, extracted slab detector 6, and an operator 7. To the operator 7 is inputted the information for every slabs by slag cards, and the max. flow through the soaking zone, the quantity of heat necessary for every slabs to be heated to a prescribed temp., temp. rise curve, and average heat absorption ratio for optional slabs are computed. A slab is then fed and a slab-detecting signal is produced from the detector 5, and the operator 7 computes the heat quantity absorbed up to now in the preheating zone 2 at intervals of a prescribed time from the measurement of actual flow. Hereby, heat quantity required by the slab is found, and if necessary, the slab temp. T' is directly found from the furnace-atmosphere temp. T. Thereafter a flow control unit 9 and the combustion of the preheating zone 2 are controlled by a calculated value corrected by use of a correction factor found from the difference between the temp. T' and the estimated temp. The heating zone 3 and the soaking zone 4 are controlled in the same manner.