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

Abstract

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.

Characterization of Nonmetallic Inclusions of Al‐Killed Ca‐Treated Steels by Automated SEM/EDS and Its Application to Industrial Case Studies

“…It is widely recognized that the chemical composition of the inclusions may affect the steel castability. [13,[65][66][67][68][69] A proper analysis of the flow control devices signal during operation can be a useful tool to evaluate casting behavior, as shown in different studies reported in the literature. [68][69][70][71][72][73][74] For stable casting conditions, if the flow control device tends to open, this means that some material is being deposited obstructing the normal flow of steel.…”

“…[6] In general, inclusions are undesired because they can decrease the production capacity of the steelshops or negatively influence the properties of steel in service. [7][8][9][10][11][12][13][14][15][16] In this context, the availability of accurate methods to characterize steel inclusions is of paramount importance to acquire knowledge about their generation and to develop ways to control them.…”

Effect of Trace of Oxygen in Ar Gas on Initial Growth of Nozzle Clogging Deposits on SEN for Ti Added Ultra‐Low C Steel Casting

“…[5,[7][8][9] While there are various roles of Ti addition to the ULC steel on the SEN clogging during continuous casting, [6,10] it is likely that Ti addition to the ULC steel influences the chemical character of the steel. It may include inclusion evolution in the steel [11][12][13] and interfacial reaction product at the inner wall of the SEN refractory. [10,[14][15][16][17] SiO 2 and C are typical components in the SEN refractory.…”

Classification of Nonmetallic Inclusions in Steel by Data‐Driven Machine Learning Methods

“…Nonmetallic inclusions have been known to affect the final properties of steel. [1][2][3][4][5] Research on nonmetallic inclusions has come a long way from focus on reduction of its overall number during steelmaking to work on modifying inclusions so as to reduce its deleterious effects and also to use it for steel microstructure optimization. [6][7][8][9][10] A continuous monitoring of nonmetallic inclusions during steelmaking is therefore given an importance so as to optimize the cleanness in the final product.…”