JPS5575867A - Prevention method of center cracking in continuous casting - Google Patents

Abstract

PURPOSE: To perform operation feedback rapidly and reduce defective material by estimating the center cracking of the slab being made based on dynamic roll gaps and operating conditions and obtaining a cause roll based on the results of the estimation.

CONSTITUTION: During continuous casting, a roll gap continuously changes owing to the changes in thermal load, mechanical load or the rolls per se and further the solidification condition of the slab relatively changes with the changes in operating conditions. When the entrapped part of molten steel occurs at the leading end of the unfrozen part on account of this and center cracking defects are produced in the slab, the following processings are performed. Namely, the dynamic roll gap during casting is mesured and solidified shell thickness is calculated from slab cooling rates, casting speeds, molten steel temperatures, steel kind components, etc. Based on these factor groups, the estimation of the presence or not of center cracking occurrence is on-line-performed and based on this, the cause roll for this is obtained. Next, based on said result, the center cracking preventive measure such as casting speed reduction is on-line- and optimum-fed back rapidly.

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