Nozzle Clogging in Steelmaking Processes

Although named “continuous”, steel continuous casting is not really a process without stops. Sooner or later the submerged entry nozzle (SEN) has to be replaced by a fresh one as it gets clogged with time. The reason for that is that the SEN material interacts with the steel and with the non-metallic particle herein leading to a growing layer of oxides forming at the inner SEN wall. This so-called clogging phenomenon is a major problem for the steel industry and has been significantly reducing  their productivity.

Therefore, this research field has the potential to optimize the casting parameters by minimizing the clogging tendency during the continuous casting of steel. It will also be important as it allows an integration into industry 4.0 as an important part of virtual/intelligent manufacturing. The developed numerical model can also be extended to investigate the clogging/fouling phenomenon (deposition and accumulation of solid suspended particles on the fluid passage) in other engineering processes, such as in heat exchangers, petrochemical industry, automotive industry food production, and pharmaceutical industries.

The corresponding aims and objectives of this research field are:

  • to develop a transient clogging model considering key physical/chemistry mechanisms: - origin of the non-metallic inclusions (NMIs); - transport of NMIs by the molten steel of high turbulence, and the effect of Ar gas; - behaviour of NMIs in the boundary layer of the nozzle wall (refractory); - adhesion mechanism of NMIs on the nozzle wall and the effect of nozzle refractory materials; - growth of the clog front and its interaction with the turbulent melt flow; - flow and possible solidification of molten steel in the clog region; fragmentation/detachment of the clog.
  • evaluation of the numerical model against available laboratory/industry experiments;
  • achievement of a fundamental understanding about the nozzle clogging in steelmaking processes, and aid the industry to optimize the process parameters.

Examples of recent achievements are given in Fig. 5. Further details on that research field can be found in

  • H. Barati, M. Wu, A. Kharicha, A. Ludwig: “A Transient Model for Nozzle Clogging”, Powder Technology 329 (2018) 181-98.
  • H. Barati, M. Wu, A. Kharicha, A. Ludwig: “Calculation accuracy and efficiency of a transient model for submerged entry nozzle clogging”, Metall. Mater. Trans. B 50B (2019) 1428-43.
  • M. Wu, H. Barati, A. Kharicha, A. Ludwig: “Using a numerical model to study the transient clogging phenomena in SEN during continuous casting of steel”, Proc. of STEESIM (8th Int. Conf. on Mod. & Simul. of Metall. Process- es in Steelmaking, Aug. 13-15, 2019, Toronto, Canada), 664-7.
  • H. Barati, M. Wu, A. Kharicha, A. Ludwig: “Discussion on possible solidification during SEN clogging in steel continuous casting”, Proc. of SG’13 (7th Int. Conf. on Solidification and Gravity), Sept. 3-6, 2018, Miskolc, Hungary, eds. Roosz A., et al., 144-9.
  • M. Wu, H. Barati, A. Kharicha, A. Ludwig: “Mathematical modeling of the early stage of clogging of the SEN during continuous casting of Ti-ULC steel”, Proc. of STEESIM (9th Int. Conf. on Mod. & Simul. of Metall. Process- es in Steelmaking, Oct. 5-7, 2021, Virtual conference), 430-4.
  • H. Barati, M. Wu, T. Holzmann, A. Kharicha, A. Ludwig: “Simulation of non-metallic inclusion deposition and clogging of nozzle”, Proc. CFD Model. Simul. in Mater. Processing, TMS 2018, In: Nastac L., Pericleous K., Sabau A., Zhang L., Thomas B. (eds), Phoenix, AZ, USA, Mar. 11-15. 2018. doi.org/10.1007/978-3-319-72059-3_15, pp. 149-158.
  • H. Barati, M. Wu, A. Kharicha, A. Ludwig: “Assessment of difference turbulence models for the motion of non-metallic inclusion in induction crucible furnace”, Proc. of LMPC (Liquid Metal Processing & Casting Conference, Sept. 20-24, 2015, Leoben, Austria), Edited by Kharicha A., Ward R.M., Holzgruber H. and Wu M., 365-71. IOP Conf. Series: Materials Science and Engineering 143 (2016) 012036

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