9th ECCC European Continuous Casting Conference – ECCC 2017

Oscillation marks (OMs) can be classified into depression OMs and hook-like OMs, near which subsurface hook structures appear in ultra-low-carbon steel of continuous casting slabs. In the current study, the hooks of whole-leaf type, truncated type, re-solidified type and double-hook type were observed, and bubbles were found below hooks, indicating that hooks could capture the floating bubbles. Inclusions from the slab subsurface near hooks were detected using automatic scanning electron microscope (ASPEX), and some inclusions were gathered near hooks which could be detrimental to the surface quality of continuous casting slabs. And more inclusions at large size were tend to gather near the hook line, indicating that large inclusions were apt to be captured by hooks. In order to minish the influence from the subsurface hooks, experiment of reducing water flow rate in the mold was conducted to decrease the hook depth. And the analyzed results demonstrated that the mean hook depth became smaller after reducing the water flow rate from 5940 L/min to 5300 L/min in wide face. Accordingly, appropriately reducing the water flow rate in the mold can minish the hook depth and the damage from the hooks.