Modeling of Inclusion Capture in a Steel Slab Caster with Vertical Section and Bending

• Main Authors: Seong-Mook Cho, Brian G. Thomas, Jong-Yeon Hwang, Jong-Geun Bang, Il-Sin Bae
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Metals
• Subjects: steels; continuous casting; inclusions; entrapment; engulfment; defects
• Online Access: https://www.mdpi.com/2075-4701/11/4/654

Particles in molten steel, including argon-gas bubbles, slag droplets, and non-metallic inclusions, are removed into the surface-slag layer or captured by the solidifying steel-shell during continuous steel casting. Captured particles often become serious defects in the final steel product, so understanding particle-capture mechanisms is important for steel quality. Slab casters often have a straight mold and upper-strand prior to a curved lower-strand. The present work investigates particle capture in such a caster using computational modeling with a standard <i>k-ε</i> model for molten-steel flow, a discrete phase model for inclusion transport, and an advanced capture criterion for inclusion entrapment and engulfment into the steel shell. A new postprocessing methodology is presented and applied to predict inclusion-capture rates in commercial cast product. The locations and size distributions of particles captured into the shell, and actual capture rates are quantified. The model predictions are validated with ultrasonic-test plant measurements of the locations of large particles captured in a steel slab. The results reveal how large-inclusion capture accumulates in the beginning of the curved strand, leading to a capture band in the slab inside radius. Finally, the capture fractions and locations due to all capture mechanisms are compared for different inclusion sizes, and the implications are discussed.