Numerical Computation for Metallurgical Behavior of Primary Inclusion in Compact Strip Production Mold

Abstract

Steady molten steel flow in CSP (Compact Strip Production) thin slab mold has been calculated via numerical simulation with heat transfer and solidification considered, and then the trajectories of inclusions have been calculated based on the flow field simulated. The solidifying shell has great influence on fluid flow and heat transfer in thin slab CSP mold, thus it should not be neglected while investigating the inclusion metallurgical behavior. The influence of solidifying shell on inclusion behavior has been particularly evaluated. Because the complex and irregular geometry of solidification front, grid of solidification front in mold has been used to judge whether inclusion is absorbed. Through the trajectories of inclusions, a statistics method to study the motion and distribution of inclusions by the “collision event” between inclusions and sampling surfaces has been used. The influence of inclusion diameter, density and casting speed on inclusion removal, also inclusion distribution within the solidifying shell in mold have been evaluated using this method. It is concluded that the distribution of inclusions in solidifying shell is not well-proportioned mainly due to fluid flow pattern in mold, diameter of inclusion, density of inclusion and casting speed. The ratio of inclusion floating to free surface decreases with casting speed rising, and the time for inclusions to float to free surface gets shorter. Inclusions with larger diameter are more possible to be frozen in solidifying shell with shallow skin depth. Removal of inclusions with smaller diameter is not sensitive to the above factors.