Article
Metallurgy & Metallurgical Engineering
Joo-Hyeok Lee, Janghoon Kim, Myeong-Hun Kang, Seong-Yeon Kim, Youn-Bae Kang
Summary: The possibility of reoxidation of Ti-ultra-low C steel by trace oxygen in Ar gas is investigated. Preliminary thermodynamic calculations show that unpurified Ar gas can cause significant oxidation of the steel, while purified Ar gas does not oxidize it. Laboratory oxidation experiments confirm the partial agreement between the calculations and the experiment, indicating the availability of oxygen and other metallic elements. Purity control of Ar gas is recommended.
STEEL RESEARCH INTERNATIONAL
(2022)
Article
Engineering, Chemical
Chengjian Hua, Yanping Bao, Min Wang
Summary: An inclusion deposition model was used to simulate nozzle clogging in industrial casting, with the introduction of concepts like inclusion parcel and inclusion magnification factor. The results were verified using industry study data, showing the formation of nozzle clogs primarily by Al-O and Al-O-Ce inclusions. The volume fraction of nozzle clog reached 52.26% by the end of the casting process, with an increase in velocity magnitude and deposition caused by 5 μm Al-O and Al-O-Ce inclusions.
Article
Chemistry, Physical
Taeheon Kim, Jae-Won Lim
Summary: Ca vapor deoxidation is important for ensuring the quality of Ti and its alloys by reducing oxygen content and improving surface properties. It results in the formation of Ca oxide layer and increased surface roughness, which further promotes oxygen diffusion and reactions with Ti/Al elements.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Chengjian Hua, Yanping Bao, Min Wang, Wei Xiao
Summary: This paper studies the numerical simulation model of nozzle clogging and the effects of relevant parameters on nozzle clogging simulation. The study examines the impact of nozzle clogging on flow, inclusion transport, and the formation process of nozzle clogging. The simulation of flow in the mold and nozzle is verified through particle image velocimetry measurement, and the simulation results of clogged nozzle are validated by industrial experiments. Findings show that the growth rate of nozzle clog increases with higher inclusion magnification factor. However, the simulation results reveal a hole in the nozzle clog, and there is a deviation between the simulated and experimental nozzle clog thickness. Increasing the random walk model parameter enhances the randomness of inclusion transport and improves the homogeneity of nozzle clog thickness simulation. Nozzle clogs initially form in the upper section of the nozzle and extend to the nozzle port. The shape of the nozzle is altered by the clogs, causing dispersion of the jet stream and reduction in its impact depth with increased solution time. The solid shell captures more inclusions, but its cleanliness decreases with longer solution time.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Limei Cheng, Lifeng Zhang, Ying Ren, Wen Yang
Summary: The clogging behavior of a submerged entry nozzle for casting sulfur-containing Ca-treated Al-killed Ti-bearing steel was investigated, revealing that the surface of clogging consisted of CaO-TiOx phase, Al2O3-MgO phase, and Al2O3-CaO-SiO2 phase. The TiOx in the clogging originated from the adhesion of inclusions in molten steel, while the silicate inclusions were formed by the reaction between low-melting-point impurities in the nozzle base material, which can alleviate nozzle clogging.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Zhe Rong, Hongbo Liu, Peng Zhang, Feng Wang, Geoff Wang, Baojun Zhao, Fengqiu Tang, Xiaodong Ma
Summary: This study investigates the formation mechanisms and evolution of complex inclusions in Ti-Ca deoxidized offshore structural steel. The number density of total inclusions generally decreases during the refining process, except for Ti and Ca addition. The major inclusions identified were CaO-Al2O3-SiO2-(MgO)-TiOx and CaO-Al2O3-SiO2. These inclusions originate from the combination of CaO-SiO2-(MgO) in refining slag or refractory and deoxidization product Al2O3 and TiO2. With the refining process and Ca addition, the composition of these inclusions changes, resulting in the promotion of intragranular acicular ferrite.
Article
Metallurgy & Metallurgical Engineering
Pengliang Jin, Deli Shang, Guocheng Wang, Yuanyou Xiao, Lei Cao
Summary: The precipitation of TiS in an Al-Ti simultaneously deoxidized steel was observed, showing the formation of single TiS, two-layered oxide (Al2O3 or TiOx)-TiS composite, and three-layered Al2O3-TiOx-TiS composite inclusions. Thermodynamic calculations revealed that the precipitation of TiS in the experimental steel during solidification is related to the solid fraction, while TiOx precipitation depends on the equilibrium partition of oxygen. The enrichment of oxygen in the residual liquid steel results in the formation of TiOx during solidification.
STEEL RESEARCH INTERNATIONAL
(2021)
Review
Metallurgy & Metallurgical Engineering
Sanjay Pindar, Manish M. Pande
Summary: The addition of titanium to Al-killed steel results in the formation of transient Al-Ti-O inclusions, which cause castability issues and enhance nozzle clogging during continuous casting. This study comprehensively reviews the formation mechanism, evolution, and modification of these inclusions in secondary steelmaking. The influence of important process parameters such as Ti addition sequence, source, presence of Mg, and Ca treatment on Al-Ti-O modification is discussed. Bridging the gaps in understanding could enhance steel cleanness in Al-killed, Ti-alloyed steel grades.
TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS
(2023)
Article
Materials Science, Coatings & Films
Tarun Babu Mangalarapu, S. Kumar, Phanikumar Gandham, Suresh Koppoju
Summary: Cold spray is the only solid-state coating technique for depositing thick metallic coatings. The deposition of metallic and metallic alloy powders is carried out at temperatures below their melting points. Successful deposition of Al-based aerospace alloys is limited to nitrogen or helium as the main process gas with a polymer nozzle to prevent nozzle clogging. However, using air as the process gas at elevated stagnation temperatures (up to 600 degrees C) has advantages in the repair and refurbishment sector, particularly in aerospace. In this study, the effect of elevated stagnation temperatures using air as the main process gas on the deposition characteristics of aerospace grade Al-alloys is investigated, and the ease of cold spray deposition of these alloys is systematically studied.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Dipak Mazumdar
Summary: A mathematical framework has been developed to quantitatively investigate inclusion floatation and generation phenomena in a tundish during continuous casting of low carbon aluminum killed steel. The analysis reveals barely satisfactory inclusion floatation coupled with significant generation, indicating essentially sub-optimal tundish process performance.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2021)
Article
Metallurgy & Metallurgical Engineering
Wei Liang, Jing Li, Bin Lu, Jian-guo Zhi, Shuai Zhang, Yang Liu
Summary: This study investigates the types of inclusions in tundish steel and the mechanism of submerged entry nozzle clogging in continuous casting of rare earth high strength steel without calcium treatment, through plant trials and thermodynamic calculations. It was found that Ce2O3 in tundish molten steel reacts with Al2O3 in the SEN refractory to form CeAlO3, leading to blockage. Improved materials and shapes of the SEN can reduce the reaction probability when calcium treatment is canceled.
JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Baohui Yuan, Jianhua Liu, Jianhua Zeng, Min Zhang, Jihong Huang, Xiaodong Yang
Summary: This study aims to analyze and improve the cleanliness of Ti-bearing IF steel produced via the long process. The results show that reoxidation leads to an increase in the number of inclusions and a decrease in their size. A new method is used to accurately evaluate the cleanliness of the steel. Weakening the reoxidation process by reducing the oxygen content, shortening the holding time, and decreasing the oxidability of the slag can enhance the cleanliness of the steel.
Article
Metallurgy & Metallurgical Engineering
Xue-feng Bai, Yan-hui Sun, Hui-bin Wu
Summary: This study systematically investigated the clogging issue of the submerged entry nozzle (SEN) during continuous casting of Ti-stabilized ultra-pure ferritic stainless (Ti-UPFS) steels. The results showed that the SEN deposit profile consisted of three major layers, with MgO·Al2O3-rich inclusions being the primary source of clogging deposits. A novel model was also established to explain the effects of complex inclusion characteristics and refractory material type on adhesion force.
JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Hongpo Wang, Peng Yu, Xiaoqing Zhou, Yu Wang, Xuewei Lv
Summary: Stability diagrams are crucial for studying deoxidation equilibrium and controlling inclusions in molten steel. Three-dimensional stability diagrams can visually show phase boundaries and transformation trends among phases. An interesting transformation of inclusions was observed in the Fe-Al-Mg-O system, where the equilibrium products of aluminum-magnesium composite deoxidation can transition between MgO, MgO·Al2O3, and Al2O3.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Metallurgy & Metallurgical Engineering
Min Jiang, Kai-lun Li, Rui-gang Wang, En-jiao Yang, Xin-hua Wang
Summary: The cleanliness and control of inclusions in Al deoxidized bearing steel were studied through industrial trials. It was found that the use of specific basic slags during the refining process resulted in better control of inclusions, with higher slag basicity and Al2O3 content leading to more desirable results. However, an increase in inclusion density and the presence of large inclusions were observed after Ar bubbling, indicating the potential risk of large inclusions in bearing steel during this process.
ISIJ INTERNATIONAL
(2022)
Article
Thermodynamics
Wan-Yi Kim, Pierre Hudon, In -Ho Jung
Summary: The newly developed model successfully describes and predicts the viscosity of oxide melts containing iron oxide, with optimized parameters to best reproduce experimental data and achieve good viscosity predictions at different compositions and temperatures.
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
(2021)
Article
Thermodynamics
Wan-Yi Kim, Pierre Hudon, In-Ho Jung
Summary: In this study, viscosity experimental data for FetO-containing silicate melts under oxidation atmosphere with Fe3+ and Fe2+ co-existing were critically evaluated and model parameters related to Fe2O3 were optimized. The charge compensation effect on the viscosity for systems containing Fe2O3 was modeled with the Gibbs energies for associate species formation. The present model successfully reproduced the viscosities of a wide range of binary, ternary and multicomponent melts containing Fe2O3-FeO-SiO2-Al2O3-CaO-MgO-Li2O-Na2O-K2O-MnO-Ti2O3-TiO2 within the scatter of experimental data.
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
(2021)
Article
Thermodynamics
Sun Yong Kwon, Reghan J. Hill, In-Ho Jung
Summary: A general flux equation for multicomponent diffusion in oxide melts is presented, with an explicit method developed to calculate the gradients of single-ion activities. The proposed model takes empirically measurable quantities as input variables, ensuring consistency with experimental data in diffusion calculations.
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
Arijit Biswas, Chandan Sahoo, Wei-Tong Du, In-Ho Jung, Manas Paliwal
Summary: Comprehensive experiments were conducted to optimize the process conditions for producing a vanadium nitride alloy, and the final alloy products were analyzed using various techniques. The study showed that thermogravimetry and X-ray diffraction are effective methods for studying the production process of vanadium nitride alloy.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2021)
Article
Materials Science, Ceramics
Jaesung Lee, Tiantian Yin, Pierre Hudon, In-Ho Jung
Summary: The phase diagram of the SnO2-SiO2 system revealed a eutectic reaction and lack of solid solution between SiO2 and SnO2. Through thermodynamic optimization based on experimental data, a new diagram was constructed and applied to simulate evaporation and condensation phenomena in float glass making process.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Ceramics
Sun Yong Kwon, In-Ho Jung
Summary: The optimized Gibbs energies of all phases in the Al2O3-ZrO2, CaO-Al2O3-ZrO2, and Al2O3-SiO2-ZrO2 systems were obtained by evaluating and assessing the available thermodynamic and phase diagram data. Key phase diagram experiments were conducted to predict and reproduce the experimental data.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
JoonHyun Nam, Marie-Aline Van Ende, In-Ho Jung
Summary: This study conducted thermodynamic analysis on the production of ferromanganese alloy in a submerged arc furnace at high temperature, and studied the slag fluxing strategy to improve manganese yield in the process. Additionally, a simulation model was developed to evaluate the energy balance and pre-reduction efficiency of the ore in the process.
Article
Thermodynamics
Min-Kyung Kim, In -Ho Jung
Summary: The liquidus in the Na2O-B2O3-Fe2O3 system in air was determined experimentally at different temperatures, and thermodynamic optimizations were carried out for the binary and ternary systems. All reliable experimental phase diagram data were successfully reproduced within the experimental error limit. Predictions of the ternary Na2O-B2O3-Fe2O3 system in air were made based on the thermodynamic models with optimized parameters.
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
Yoongu Kang, Min-Kyu Paek, In-Ho Jung
Summary: This study thermodynamically assessed the Mo-C, Mo-N, and Mo-C-N systems using the Calculation of Phase Diagram (CALPHAD) method, and significantly improved the description of the phase diagrams and thermodynamic data by optimizing the model parameters.
JOURNAL OF MATERIALS RESEARCH
(2022)
Article
Metallurgy & Metallurgical Engineering
Zhimin You, Mingze Ran, Zhouhua Jiang, Min-Kyu Paek, In-Ho Jung
Summary: The thermodynamic behavior of nitrogen (N) in the Fe-Cr-Mn-C-N liquid solution is modeled using the Modified Quasichemical Model with consideration of short-range ordering. New model parameters for the Fe-Cr-Mn-C-N liquid solution are determined based on an evaluation of experimental data. The solubility of N in the Fe-Cr-Mn-C-N system is optimized for various temperatures and N-2 pressures, and the thermodynamic properties of N in Fe-based liquid solution affected by alloying elements are calculated from the developed thermodynamic database.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Guishang Pei, Junyi Xiang, In-Ho Jung, Mengjiao Jiao, Zhuoyang Li, Xuewei Lv
Summary: A Ca5Mg4V6O24 compound was synthesized through solid-state roasting routes and its crystal structure and thermodynamic properties were determined. The compound crystallizes in cubic space group Ia3d with a = 12.442 +/- 0.001 angstrom. X-ray photoelectron spectroscopy confirmed the presence of vanadium in the +5 state. The melting point of Ca5Mg4V6O24 was found to be 1442 K. The molar heat capacity (374 J mol K-1) and entropy (688.2 J mol K-1) at 298.15 K were determined using physical properties measurement system and simultaneous thermal analyzer for the first time. The solubility of Ca5Mg4V6O24 in water at different temperatures was measured, and its dissolution behavior in sulfuric acid and kinetics were experimentally established.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Ceramics
Seungjoo Baek, In-Ho Jung
Summary: The phase diagram of the MgO-Y2O3-MgF2-YF3 system was studied for the first time using experimental techniques and thermodynamic modeling. No ternary or quaternary crystalline phase was observed, and the eutectic reactions in the system were identified. The overall phase diagram was calculated using the CALPHAD method.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Zhimin You, Hao Zhang, Senlin Cui, Zhouhua Jiang, In-Ho Jung
Summary: Thermodynamic modeling of the Si-P and Si-Fe-P systems was performed using the CALPHAD method. The liquid and solid solutions were described using the Modified Quasichemical Model and Compound Energy Formalism, respectively. The phase boundaries and Gibbs energies were reoptimized and carefully determined to resolve discrepancies in previously assessed phase diagrams of the Si-Fe-P system.
Article
Materials Science, Ceramics
Jaesung Lee, In-Ho Jung
Summary: The phase diagram of the Na2O-Al2O3-ZrO2 system was experimentally studied and thermodynamically modeled, providing important information about the system's phase equilibria and thermodynamic properties.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Ceramics
Xiaofei Zhu, Yulei Zhang, Jian Zhang, Tao Li, In-Ho Jung, Yangyang Su, Wenhan Gai
Summary: A composite coating containing B2O3 glass was prepared on SiC-coated C/C composites to enhance their oxidation resistance at temperatures ranging from 1173 to 1773 K. Borosilicate and SiO2 glasses acted as oxygen barriers at different temperature ranges. The addition of Hf-oxides ceramic particles improved the thermal stability and crack resistance of the glass layer. The composite coating effectively protected the C/C composites against oxidation, with mass gains ranging from 3.77 g·m(-2) to 21.41 g·m(-2) after exposure to high temperatures.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
