2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 6: Yagi Intl. Symp. / Metals & Alloys Processing
| Editors: | Kongoli F, Akiyama T, Nogami H, Saito K, Fujibayashi A |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 480 pages |
| ISBN: | 978-1-987820-46-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
The Prenucleation Alumina Clusters during Aluminum Deoxidation Reaction Process in Liquid Iron
Guocheng Wang1;1, Anshan, China;
Type of Paper: Regular
Id Paper: 28
Topic: 3
Abstract:
Crystal nucleation plays a decisive role in determining the crystal structure and size distribution of the crystal inclusions in molten steel. Until now, the knowledge does not yet provide a clear picture about the pathway leading 再-Al2O3 inclusion from molten steel. Especially, it is unclear that the structure and thermodynamic properties of prenucleation alumina clusters and cluster aggregates in the nucleation process. In the current work, the thermodynamic equilibrium experiments and model studies on the aluminum deoxidation reaction in liquid iron since the 1950s are summarized systematically, moreover, the industrial experimental data of aluminum deoxidation refining are compared with the thermodynamic equilibrium curves. It is revealed that the existence of metastable alumina phase in aluminum-deoxidation process, based on thermodynamic properties of metastable alumina phase and the difference in terms of the experimental results and equilibrium curves. Furthermore, the thermodynamics of metastable prenucleation alumina clusters, the excess oxygen and supersaturation degree of Al and O for nucleation are analyzed by the two-step nucleation mechanism. The prenucleation analysis suggested that alumina clusters gathering into cluster aggregates are the restricted step of 再-Al2O3 nucleation and a decisive factor to reduce the nucleation rate. In order to control the size distribution of alumina inclusions, based on the thermodynamic point of view, it could be effective to separate alumina clusters formation and the growth of 再-Al2O3 crystal with size more than 10 nm.