Flow pattern in ingot during mould filling and its impact on inclusion removal

Abstract

A two-dimensional non-steady state computational fluid dynamic model was employed to gain a basic understanding of the flow in the ingot during casting. The surface velocity was found to be affected by the inlet angle and was found to vary with the casting level. The information of surface velocity was related to the probability of the inclusion removal. Water model experiments were also conducted to help the understanding. The model calculation revealed the same trends as the results of water model experiments. Both computational fluid dynamic data and the physical modelling showed that the inlet angle of 5u currently used in the industry was a good alternative regarding inclusion removal. The present work suggests strongly that the melting shop should try to obtain a liquid or semiliquid film at as early stage as possible in ingot casting.

Simulation of ingot casting processes at Deutsche Edelstahlwerke GmbH®

“…For manganese the calculated values correlate very well with the measured ones, whereas for carbon the value differs clearly at the top of the ingot. This difference could be caused by the fact, that pickup of carbon from the insulation and the covering powder is not taken into account [8]. Also, the results for the high-alloyed element chromium varied along the centreline.…”

Comprehensive Numerical Simulation of Filling and Solidification of Steel Ingots

“…This result can be achieved by properly design the running system, in particular the nozzle angle. Different authors have already shown the advantages of using a divergent nozzle, also with the addition of a swirl [ 18 , 20 , 27 , 28 ]. In this case, the filling should be strongly improved by increasing the inlet nozzle angle and by adding a shock absorber at the end of the horizontal channel.…”

An Experimental and Numerical Study of the Free Surface in an Uphill Teeming Ingot Casting Process

“…Therefore, these inclusions are hard to remove from liquid steel, as the separation time is limited. Thus, many investigations have been performed to find ways to eliminate or reduce the formation of inclusions that originate from the mold flux.…”

“…The results showed that a 25 ° angle of the inlet nozzle can reduce the risk of slag entrapments, leading to an almost flat rising surface and low surface velocities. Ragnarsson also investigated the opening angle in an ingot casting process where both water model experiments and numerical simulations were performed with a large range of opening angles. Their findings indicated that the inlet angle of 5° used in the industry was a good alternative with respect to the inclusion removal.…”