Prediction and control of subsurface hooks in continuous cast ultra-low-carbon steel slabs

G. G. Lee, H. J. Shin, S. H. Kim, S. K. Kim, W. Y. Choi, B. G. Thomas

Research output: Contribution to journalArticlepeer-review


Subsurface hook formation during initial solidification in the continuous casting mould degrades the quality of steel slabs owing to the associated entrapment of argon bubbles and non-metallic inclusions. To minimise hook depth and to improve slab quality, extensive plant experiments were performed and analysed to quantify the effect of casting parameters on hook characteristics using the no. 2-1 caster at POSCO Gwangyang Works, Korea. The results reveal that meniscus heat flux plays an important role in controlling hook characteristics. Hook depth correlates with oscillation mark depth, hook shell thickness, and hook length. Based on regression analysis, this paper proposes an equation to predict hook depth in ultra-low-carbon steels as a function of casting speed, superheat, oscillation frequency, surface level fluctuations, and mould flux properties. Use of this quantitative equation enables improved control of subsurface quality in the continuous casting of steel slabs.

Original languageEnglish (US)
Pages (from-to)39-49
Number of pages11
JournalIronmaking and Steelmaking
Issue number1
StatePublished - Jan 2009
Externally publishedYes


  • Continuous casting
  • Hook
  • Oscillation marks
  • Solidification microstructure
  • Subsurface quality
  • Ultra low carbon steel

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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