The method on the prediction the falling of clogging material in the submerged entry nozzle and operation method of finishing line at continuous casting

摘要

PURPOSE: An operation method for correcting continuous casting by detecting falling of clogging material into the submerged entry nozzle for continuous casting is provided to prevent clogging of the submerged entry nozzle without blow hole defects by controlling amount of inert gas blown into upper nozzle and submerged entry nozzle. CONSTITUTION: The operation method comprises the steps of predicting falling degree of materials stuck to an inner part of the submerged entry nozzle by measuring vibration characteristics of the submerged entry nozzle generated in case that the materials stuck to the inner part of the submerged entry nozzle are fallen from the submerged entry nozzle; and reducing surface defects of inclusions by increasing the number of scarfing treatment operations in continuous casting correction based on the maximum falling index obtained per casting slab unit, wherein a method for measuring falling of materials stuck to the inside of the submerged entry nozzle comprises the steps of collecting vibration signals of the submerged entry nozzle to 256 frequencies per second or more using a laser doppler vibrometer, and adding up vibration values by integrating frequency signals obtained from frequency band of 1 to 7 Hz by performing frequency analysis.