Assessment of Reactivity between Submerged Entry Nozzle (SEN) and Ultra‐low C Liquid Steel: Comparison between Oxide‐Based SEN and Oxide‐Less SEN

Abstract

Submerged entry nozzle (SEN) clogging is investigated with an emphasis on the interfacial reaction between the nozzle refractory and the liquid steel. Within the context of carbothermically produced CO(g) being the main cause of the early stage SEN clogging, various SEN refractory materials are assessed in view of their impact on the initial clog deposit formation. A series of high‐temperature experiments are carried out to observe the interfacial reaction between the SEN refractory materials and the liquid steel: three oxide‐based and one oxide‐less refractory materials are employed. Ti‐free and Ti‐added ultra‐low C steel are reacted with these refractory materials. The reactivity of the refractories is assessed by 1) the morphology, composition, and thickness of the initial clog deposit and 2) the evolution of steel compositions. Decreasing SiO2 content in “oxide‐based” refractory is recommended. The “oxide‐less” refractory composed of AlON–BN–AlN is shown to be promising to suppress the early stage of SEN clogging. The present results would provide directions for designing the SEN refractory constitution to suppress the SEN clogging.