METHOD FOR PREDICTING CLOGGING OF SUBMERGED NOZZLE

摘要

PURPOSE: A method for predicting clogging of submerged nozzle is provided to prevent defects of casting slab by measuring surface temperature of the submerged nozzle, thereby realtime predicting clogging degree of the nozzle from the initial period of casting. CONSTITUTION: The method comprises a step of continuously measuring temperature variation of the nozzle surface by always contacting a thermocouple(10) with the surface of the submerged nozzle(8) during casting; and a step of calculating thickness of clogging layer of the nozzle by substituting information on width of the measured temperature variation for the following expression 1: clogging layer thickness=-0.05073+0.03249x(ΔT)-1.73467x10¬-5x(ΔT)¬2+1.83785x10¬-7x(ΔT)¬3, where ΔT is temperature variation of the nozzle surface, wherein the expression 1 on the clogging layer thickness is calculated from a relation between the two data by using a difference between the maximum temperature of the submerged nozzle in the early stage of casting and a final temperature of the submerged nozzle after finishing casting as one data and thickness of clogging layer of temperature measuring part in the submerged nozzle recovered after casting as another data, and wherein a castable insulator(12) formed of ceramic material is covered on the front end of the thermocouple so that the thermocouple is not directly contacted with the submerged nozzle, and the thermocouple is assembled in such a way that the thermocouple is always contacted with the submerged nozzle by spring(24).