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VERSION:2.0
METHOD:PUBLISH
BEGIN:VEVENT
ORGANIZER;CN=ESTAD 2023:mailto:info@metec-estad.com
LOCATION:Room 16b
SUMMARY:SEN clogging during continuous casting: mechanism and countermeasure in chemistry aspect
DESCRIPTION:Continuous casting of liquid steel from tundish to mold is performed by flowing the liquid steel through SEN. However, the inner hole of the SEN is often clogged, and consequently, the casting process is interrupted.  The clogging deposit also falls off,  enters into the liquid steel in the mold, and eventually appears on the surface of the cast product.  Suppressing nozzle clogging is therefore essential to increase the productivity and quality of the cast product.  While various origins have been identified for causing nozzle clogging, the present study focuses on the reaction chemistry-based aspect.  The initiation of the clogging is due to an interfacial reaction between the inner wall of the SEN and the liquid steel passing through the SEN. In particular, the carbothermic reaction inside the SEN (SiO2(ref.) + 3C(ref.) = 2CO(g) + SiC(s)) generates CO(g), which causes reoxidation of the liquid steel, resulting in clog deposit formation.  This initial clog deposit can be a subsequent build-up site for inclusions in the liquid steel. Therefore, it is necessary to suppress the reoxidation.  In the present study, the fundamental reaction is discussed in view of thermodynamics, a series of laboratory-scale experiments including in-situ gas analysis in the emitted gas, and proposals to suppress the CO(g) generation.  Three approaches will be shown: 1) minimizing SiO2/C ingredients, 2) adding CO absorbers, and 3) replacing SiO2/C ingredients with non-oxide type ingredients (oxynitride-nitride mixture)  in the SEN refractory.  Significantly improved results were obtained, in terms of suppressing clog deposit growth and casting plant trials.
CLASS:PUBLIC
DTSTART:20230615T141000
DTEND:20230615T143000
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