Fluid Flow and Steel Cleanliness in a Continuous Casting Tundish and Mold

The increasing requirement for clean steel has made tundish metallurgy a key step in the steelmaking process to obtain excellent steel quality [1]. Flow control devices like weirs and dams are the most common techniques applied in tundish metallurgy since they typically increase the residence time of liquid steel in the tundish, effectively promote the floatation and removal of inclusions and dampen variations in the composition and temperature. It is common knowledge that the proper combination of weirs and dams can optimize the fluid flow by increasing the fraction in the plug flow zone and in the mixing flow zone while reducing the fraction in the dead zone, thus promoting the removal of inclusions. The mold is the final step to remove more inclusions from the molten steel. Fluid flow in the mold has a great impact on the motion, entrapment and removal of inclusions, on heat conduction of the initially solidified shell and on the quality of the cast product. The proper flow field in the mold can lower the level fluctuation, reduce the depth of the oscillation marks, promote uniform growth of the shell, promote the floating and removal of inclusions and bubbles and therefore decrease the surface defects in the cast product