<p>Steel
refining via ladle treatment is critical to final product quality in the steel
manufacturing process. The process of ladle refining serves to assist in the
removal of non-metallic inclusions, which can impact steel product fatigue
strength, impact toughness, and corrosion resistance. While the steelmaking
industry has in place best practices for the process, it remains costly to
performing trial and error testing on the ladle. In addition, an understanding
of the flow phenomena within the ladle during operation can provide industry
with key knowledge necessary to improve the efficiency and throughput of the
process.</p>
<p> </p>
<p>The
method by which this research aims to address this is through the development
of a comprehensive computational fluid dynamics (CFD) model of the steelmaking
ladle. Such a model, capable of predicting the inclusion removal process and
flow patterns within the ladle, would serve to provide the necessary
information to advance steelmaking efficiency and improve product quality. A
full scale unsteady state three dimensional CFD model has been developed to
predict removal of inclusion during gas-stirring in a ladle. The
Eulerian-Eulerian model was used to simulate the multiphase flow, the
Population Balanced Model (PBM) has been used to describe the inclusion
distribution. The phenomena of bottom-blow argon bubble coalescence and breakup
were considered. </p>
<p> </p>
<p>Additionally,
a model has been developed to predict inclusion removal during operation. For
the inclusion removal model, the CFD-PBM coupled method has been
proposed to investigate the inclusion behavior. This includes representing
phenomena such as inclusion-bubble collision, inclusion removal by attachment
to the ladle refractory, and inclusion capture by slag floating on the surface
of the melt. The unified computational model for simulation of fluid flow and
inclusion removal was validated against industry measurements provided by Nucor
Steel. </p>
<p> </p>
<p>Using
this CFD model and a ladle geometry and set of baseline conditions provided by
Nucor Steel, studies were carried out to examine flow development, gas bubble
distribution, and inclusion removal. Examining the impacts of inclusion size on
removal rate indicated that larger inclusions are removed faster. This agreed
with both industry expectations and data found in published literature. In
addition, the model predicts that bubble-inclusion collision are primarily
responsible for 99% inclusion removal in a gas-stirred ladle.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7455167 |
| Date | 16 January 2019 |
| Creators | Wenjie Liu (5930981) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Study_of_Inclusion_Removal_in_a_Gas-stirred_Ladle/7455167 |
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