Modeling of the dynamic-bulging-induced surface level fluctuations in continuous casting

Zhengtao Xu, Zhelin Chen, Lu Chen, Bryan Petrus, Madison Milligan, Daniel Stephens, Joseph Bentsman, Brian G. Thomas

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Mold level fluctuations in continuous casting of steel slabs give rise to slag inclusions, strand surface cracks, and, in severe cases, breakouts. One of the main causes of mold level fluctuations is dynamic bulging, which arises due to periodic squeezing of the strand in the spray cooling zones beneath the mold. This paper presents two models to predict the effect of dynamic bulging on liquid level variations. The first model estimates mold level variations due to dynamic bulging based on two submodels: 1) a computational heat flow model of the continuous casting process that outputs strand surface temperature and shell thickness to an empirical equation to estimate the maximum inner-roll bulging amplitude under steady casting conditions, and 2) an analytical geometric model that calculates the dynamic shape of the bulged shell and the resulting mold level fluctuations, based on the output from the first model and an assumed frozen fraction history. The second model is a simple analytical calculation of the dynamic bulging effect based on the difference between two plant measurements: the mold level sensor data and the stopper rod position, together with a model that predicts the effect of inlet flow variations from the tundish through the SEN into the mold under transient conditions, caused by the measured stopper rod movements, including the effects of erosion. The predictions from these two models are compared to gain new insight into the mold level fluctuations caused by dynamic bulging. At present, this comparison shows quantitative similarities, but also noticeable discrepancy. Steps to improve the accuracy of both models are discussed.

Original languageEnglish (US)
Title of host publicationProceedings of the Iron and Steel Technology Conference, AISTech 2020
PublisherIron and Steel Society
Number of pages16
ISBN (Electronic)9781935117872
StatePublished - 2020
EventAISTech 2020 Iron and Steel Technology Conference - Cleveland, United States
Duration: Aug 31 2020Sep 3 2020

Publication series

NameAISTech - Iron and Steel Technology Conference Proceedings
ISSN (Print)1551-6997


ConferenceAISTech 2020 Iron and Steel Technology Conference
Country/TerritoryUnited States


  • Continuous casting
  • Dynamic bulging
  • Frozen fraction
  • Heuristic geometric modification
  • Shell profile
  • Shell thickness

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering


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