Improvement of Slab Subsurface Quality by Change of Casting Parameters in Continuous-cast Ultra-low-carbon Steels

by Sung-Kwang Kim, Ho-Jung Shin, Young-Kwan Park, Joo-Choi, Go-Gi Lee, Seon-Hyo Kim

Publisher - POSCO Steelmaking Department, POSTECH, South Korea

Category - General Novel

Subsurface hook formation at the initial solidification in mold during continuous casting of steel slabs degrades slab quality owing to the entrapment of argon bubbles and non-metallic inclusions near the hooks. To minimize the hook and to improve the slab quality, plant experiments were performed to quantify the effect of casting parameters on hook characteristics by an intensive experimental campaign using a #2-1 caster at POSCO Gwangyang Works, South Korea. Heat flux plays an important role in controlling hook characteristics by the results obtained from plant experiments. Other casting conditions which are related to heat flux near the meniscus region such as casting speed, superheat, oscillating conditions, surface level fluctuation and mold flux property were investigated to quantity the effect of heat flux on hook characteristics. Developing these results, this paper proposes regressive equations for prediction of hook depth. Use of this equation enables both the quantitative prediction and the improvement of slab subsurface quality in the continuous casting of steel slabs.

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