A new mechanism of hook formation during continuous casting of ultra-low-carbon steel slabs

Joydeep Sengupta, Brian G. Thomas, Ho Jung Shin, Go Gi Lee, Seon Hyo Kim

Research output: Contribution to journalArticlepeer-review


The initial stages of solidification near the meniscus during continuous casting of steel slabs involve many complex inter-related transient phenomena, which cause periodic oscillation marks (OMs), subsurface hooks, and related surface defects. This article presents a detailed mechanism for the formation of curved hooks and their associated OMs, based on a careful analysis of numerous specially etched samples from ultra-low-carbon steel slabs combined with previous measurements, observations, and theoretical modeling results. It is demonstrated that hooks form by solidification and dendritic growth at the liquid meniscus during the negative strip time. Oscillation marks form when molten steel overflows over the curved hook and solidifies by nucleation of undercooled liquid. The mechanism has been justified by its explanation of several plant observations, including the variability of hook and OM characteristics under different casting conditions, and the relationships with mold powder consumption and negative/positive strip times.

Original languageEnglish (US)
Pages (from-to)1597-1611
Number of pages15
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Issue number5
StatePublished - May 2006
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys


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