scholarly journals Experimental Study on the Behavior of TiN and Ti2O3 Inclusions in Contact with CaO‐Al2O3‐SiO2‐MgO Slags

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
S. K. Michelic ◽  
C. Bernhard
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Stainless Steels ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Dissolution Behavior ◽  
Inclusion Removal ◽  
Scanning Confocal Microscopy ◽  
Effective Removal ◽  
Final Steel

TiN and Ti2O3 are the predominant inclusion types in Ti-alloyed ferritic chromium stainless steels. In order to ensure the required steel cleanness level, an effective removal of such inclusions in the slag during secondary metallurgy is essential. This inclusion removal predominantly takes place via dissolution of the inclusion in the slag. The dissolution behavior of TiN and Ti2O3 in CaO-SiO2-Al2O3-MgO slags as well as their agglomeration behavior in the liquid steel is investigated using High Temperature Laser Scanning Confocal Microscopy and Tammann Furnace experiments. Thermodynamic calculations are performed using FactSage 7.0. The behavior of TiN is observed to be completely different to that of oxides. Ti2O3 dissolves quickly in slags, and its dissolution behavior is comparable to that of other already well examined oxides. In contrast, TiN shows a very intense gas reaction which is attributed to the release of nitrogen during contact with slag. Slags with higher SiO2 content show a significantly higher ability for the dissolution of TiN as compared to Al2O3-rich slags. The gas reaction is found to also significantly influence the final steel cleanness. Despite the easy absorption of TiN in the slag, the formed nitrogen supports the formation of pinholes in the steel.

scholarly journals Dissolution Behavior of Different Inclusions in High Al Steel Reacted with Refining Slags

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1801
Author(s):  
Shuo Zhao ◽  
Zushu Li ◽  
Renze Xu ◽  
Darbaz Khasraw ◽  
Gaoyang Song ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Steel Slag ◽  
Laser Scanning Confocal Microscopy ◽  
Dissolution Time ◽  
Dissolution Behavior ◽  
Scanning Confocal Microscopy ◽  
Composite Oxides ◽  
Secondary Refining ◽  
High Temperature Furnace ◽  
Effective Removal

Al2O3, Al2O3·TiN, Al2O3·MgO, and CaO·2Al2O3 are four different types of inclusions in high Al steels. To improve the steel cleanness level, the effective removal of such inclusions during secondary refining is very important, so these inclusions should be removed effectively via inclusion dissolution in the slag. The dissolution behavior of Al2O3, Al2O3·TiN, Al2O3·MgO, and CaO·2Al2O3 in CaO-SiO2-Al2O3-MgO slags, as well as the steel-slag reaction, was investigated using laser scanning confocal microscopy (LSCM) and high-temperature furnace experiments, and thermodynamic calculations for the inclusion in steel were carried out by FactSage 7.1. The results showed that Al2O3·TiN was observed to be completely different from the other oxides. The composite oxides dissolved quickly in the slags, and the dissolution time of the inclusions increased as their melting point increased. SiO2 and B2O3 in the slag were almost completely reacted with [Al] in steel, so the slags without SiO2 showed a positive effect for avoiding the formation of Al2O3 system inclusions and promoting inclusions dissolution as compared with SiO2-rich slags. The steel-slag reaction was also found to influence the inclusion types in steel significantly. Because of the rapid absorption of different inclusions in the slag, it was found that the dissolution time of inclusions mainly depends on the diffusion in the molten slag.

Two-Dimensional Transient Heat Transfer Model for High-Temperature Laser-Scanning Confocal Microscopy

2021 ◽  
Author(s):  
Dasith Liyanage ◽  
Suk-Chun Moon ◽  
Ajith S. Jayasekare ◽  
Abheek Basu ◽  
Madeleine Du Toit ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Transformation ◽  
High Temperature ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Transfer Model ◽  
Two Dimensional ◽  
Scanning Confocal Microscopy ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract High-temperature laser-scanning confocal microscopy (HT-LSCM) has proven to be an excellent experimental technique through in-situ observations of high temperature phase transformation to study kinetics and morphology using thin disk steel specimens. A 1.0 kW halogen lamp, within the elliptical cavity of the HT-LSCM furnace radiates heat and imposes a non-linear temperature profile across the radius of the steel sample. This local temperature profile when exposed at the solid/liquid interface determines the kinetics of solidification and phase transformation morphology. A two-dimensional numerical heat transfer model for both isothermal and transient conditions is developed for a concentrically solidifying sample. The model can accommodate solid/liquid interface velocity as an input parameter under concentric solidification with cooling rates up to 100 K/min. The model is validated against a commercial finite element analysis software package, Strand7, and optimized with experimental data obtained under near-to equilibrium conditions. The validated model can then be used to define the temperature landscape under transient heat transfer conditions.

Experimental study of moiré method in laser scanning confocal microscopy

2006 ◽  
Vol 77 (4) ◽  
pp. 043101 ◽  
Author(s):  
Bing Pan ◽  
Huimin Xie ◽  
Satoshi Kishimoto ◽  
Yongmin Xing
Keyword(s):  
Experimental Study ◽  
Confocal Microscopy ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy ◽  
Moire Method

Exploring the Ti-5553 phase transformations utilizing in-situ high-temperature laser-scanning confocal microscopy

2020 ◽  
Vol 159 ◽  
pp. 110013
Author(s):  
Kaio Niitsu Campo ◽  
Leonardo Fanton ◽  
Mariana Gerardi de Mello ◽  
Suk-Chun Moon ◽  
Rian Dippenaar ◽  
...  
Keyword(s):  
High Temperature ◽  
Confocal Microscopy ◽  
Phase Transformations ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy

scholarly journals Friction and Wear Behaviors of Fe-19Cr-15Mn-0.66N Steel at High Temperature

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1285
Author(s):  
Shaolong Sheng ◽  
Huiling Zhou ◽  
Xiaojing Wang ◽  
Yanxin Qiao ◽  
Hongtao Yuan ◽  
...  
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Friction And Wear ◽  
Laser Scanning Confocal Microscopy ◽  
Wear Testing ◽  
Oxide Layers ◽  
X Ray ◽  
Scanning Confocal Microscopy

The friction and wear behaviors of Fe-19Cr-15Mn-0.66N steel were investigated under applied loads of 5 N and 15 N at the wear-testing temperatures of 300 °C and 500 °C using a ball-on-disc tribometer. The wear tracks were evaluated by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM) to reveal the variation in morphologies. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to determine the components of oxide layers formed on wear surfaces. The results demonstrated that the oxide layers are favorable for obtaining a low friction coefficient under all conditions. The average friction coefficient decreased with increasing load at 300 °C, while it increased with the increase in applied load at 500 °C. At 300 °C, severe abrasive wear characterized by grooves resulted in a high friction coefficient with 5 N applied, whereas the formation of a denser oxide layer consisting of Cr2O3, FeCr2O4, Fe2O3, etc., and the increased hardness caused by work hardening led to a decrease in friction characterized by mild adhesive wear. At 500 °C, the transformation of Fe2O3 to the relatively softer Fe3O4 and the high production of lubricating Mn2O3 resulted in a minimum average friction coefficient (0.34) when 5 N was applied. However, the softening caused by high temperature weakened the hardening effect, and thus the friction coefficient increased with 15 N applied at 500 °C.

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