Significance of Nonmetallic Inclusions for the Clogging Phenomenon in Continuous Casting of Steel––A Review

• Published in: Steel research international Vol. 93; no. 7
• Main Authors: Michelic, Susanne K., Bernhard, Christian
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.07.2022
• Subjects: adhesion; clogging; contact angle; Continuous casting; deposition; Flow control; Interfacial properties; Iron and steel making; Low carbon steels; Nonmetallic inclusions; refractory wall; State-of-the-art reviews; Steel; Wetting
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.202200086

Nonmetallic inclusions are well known to influence product quality and process stability in the production of steel. A process step that is very sensitive to the presence of nonmetallic inclusion (NMI) is continuous casting. Here, the so‐called clogging phenomenon can occur, resulting in a distinct disruption of the casting process and decreased steel quality. The presence of nonmetallic inclusions considerably contributes to the build‐up of deposits in the submerged entry nozzle provoking instabilities in the flow control system. Numerous research studies have been subject to different clogging mechanisms and related influencing parameters. Interfacial properties significantly influence the behavior of inclusions in the steel–refractory system. The present review demonstrates state of the art concerning the role of NMIs in the appearance of clogging. Particular focus is put on the wetting behavior between the different phases and their consequence for the deposition process. Industrial observations and laboratory methods are summarized and discussed; potential countermeasures are evaluated. A steel group that is especially prone to clogging are Ti‐ ultra low carbon (ULC) steels. An overview of the current understanding of their high clogging tendency and possible influences is presented, considering thermodynamic and interfacial aspects. Clogging is still a vivid problem in the continuous casting of steel. The presence of NMIs significantly contributes to the formation of build‐ups in the flow control system. The role of interfacial reactions in the system steel‐inclusion‐refractory is discussed in detail. Particular focus is put on the clogging sensitivity of Ti‐ ultra low carbon (ULC) steels.