JPS645666A - Method for cutting cast slab - Google Patents

Abstract

PURPOSE:To improve the cutting efficiency of the titled cast slab by detecting the preheating temperature automatically optically and blowing out oxygen for cutting from blowpipes after the preheating temperature attains a proper value to perform the cutting and preventing the occurrence of the defective cutting and moreover, eliminating the need for a full-time worker. CONSTITUTION:The blowpipes 71 and 72 and optical detectors 91 and 92 are stopped at the side edges of the cast slab 1 and gases for preheating are blown out from the blowpipes 71 and 72 and both side edges of the cast slab 1 are preheated by gas flames and the radiant energy quantities from the preheating parts are measured by the optical detectors 91 and 92. In this case, a composite value of the radiant energy generating from the preheating parts and the radiant energy generating from the flames for preheating is measured with the ordinary measurement. Accordingly, preheating is measured with the ordinary measurement. Accordingly, only the energy of a zone peculiar to the radiant energy from the preheating parts is easily selected and detected and the temperature of the preheating parts is accurately detected by a thermometer 11. The temperature of the preheating parts is inputted to a control part 12 and when it attains the predetermined threshold temperature, a control signal is sent to a control valve 13 and the preheating gases and cutting oxygen are blown out from the blowpipes 71 and 72 to perform the sure cutting.