Interfacial Reaction between Al2O3–SiO2–C Refractory and Al/Ti-Killed Steels

Abstract

In the current investigation, the thin film method was employed to clarify the formation mechanism of the oxide layers at the interface between the Al2O3-SiO2-C refractory and liquid Fe. A reacted layer was formed in such a way that initially FeO-enriched liquid layers are widely distributed on the Fe surface and FeO and SiO2 in the liquid layer are reduced by Al in liquid Fe to develop solid Al2O3-enriched layer of inclusions. Some inclusions in liquid Fe might be produced by the remaining oxygen in Ar gas being supplied through the nozzle to prevent the adherence of inclusions onto it. The oxide layers at the interface estimated by thermodynamic calculation are in good accordance with the experimental results of the reaction between Al2O3-SiO2-C refractory and Al-killed/Al-Ti-killed steels previously reported.

Effect of Trace of Oxygen in Ar Gas on Initial Growth of Nozzle Clogging Deposits on SEN for Ti Added Ultra‐Low C Steel Casting

“…Lee et al reported a possibility of inclusion formation in liquid Fe in equilibrium with “Ar 5 N (deoxidized)” gas, which was purified by Mg turning as was done similarly in the present study, and “Ar 5 N (non‐deoxidized)” gas without the purification, respectively. [ 39 ] They intentionally exposed a liquid Fe at 1550 °C either to the “Ar 5 N (deoxidized) or the “Ar 5 N (non‐deoxidized)” for 3 h, and analyzed dissolved O content. An initial oxygen content (0.05%) increased to approximately 0.07% by the “Ar 5 N (deoxidized)” or 0.11% by the “Ar 5N (non‐deoxidized)”, respectively.…”

Analysis of Fluid Flow of Liquid Steel through Clogged Nozzles: Thermodynamic Analysis and Flow Simulations

“…ðAl 2 OÞ AG ¼ 2½Al Fe þ ½O Fe (4) ðCOÞ AG ¼ ½C Fe þ ½O Fe (5) Fukuda et al [2] conducted experiments immersing AG materials in molten Fe-Al alloys corroborating these reactions. The dissolved oxygen reacts with aluminum in steel to precipitate alumina, forming a dense network adhered to the internal wall of the nozzle, as shown in Equation (6).…”

“…2½Al Fe þ 3½O Fe ¼ hAl 2 O 3 i Fe (6) Regarding Ti additions to steel, it is generally known that nozzle clogging during casting Ti-stabilized ultralow-carbon steels (Ti-SULC) is more severe and takes shorter forming times than when casting low-carbon aluminum-killed steels (LCAKS). [4] Accordingly, Ti can be oxidized through similar reactions. [5] 5ðSiOÞ AG þ 3½Ti Fe ¼ hTi 3 O 5 i þ 5½Si Fe (7) 5ðCOÞ AG þ 3½Ti Fe ¼ hTi 3 O 5 i þ 5 ½C Fe (8) Regarding the steelmaking process, Van Ende et al [6] reported the importance of previous steel deoxidation with a minimum aluminum content of about 200 ppm before adding later 500 ppm of Ti and avoiding its reoxidation.…”

“…Regarding Ti additions to steel, it is generally known that nozzle clogging during casting Ti‐stabilized ultralow‐carbon steels (Ti‐SULC) is more severe and takes shorter forming times than when casting low‐carbon aluminum‐killed steels (LCAKS). [ 4 ] Accordingly, Ti can be oxidized through similar reactions. [ 5 ] …”

Alumina Nucleation, Growth Kinetics, and Morphology: A Review

“…These titanium effects on the steel lead to better interfacial contact between the steel and the nozzle, leading to accelerated nozzle clogging in shorter times in Ti‐SULC than in Al‐killed steels. [ 171–176 ]…”