Behavior of Mold Slag Used for 20Mn23Al Nonmagnetic Steel During Casting

Xiong, Yu; Wen, Guangrui; Tang, Ping; Ma, Fanjun; Wang, Huan

doi:10.1016/s1006-706x(11)60005-8

Cited by 45 publications

(24 citation statements)

References 7 publications

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“…(1). The reaction mechanism that is proposed by the present simulations is in good agreement with that suggested in literature 2,3,36,38) since the model is built by combining kinetic expressions with an accurate thermodynamic database. Unfortunately, no mold flux study in the transition period of molten steel has been reported.…”

Section: Simulation Of Mold Flux Composition During Thesupporting

confidence: 89%

“…More remarkably, the model can reproduce the observed characteristics of the Al2O3 accumulation with casting time: a fast increase of the Al2O3 content followed by a steady state. 2,3) The predicted steady state value and the time required to reach it are also in good agreement with experimental results 2,3) (25 to 35 wt% Al2O3 within 15 min with various Al content in steel, casting conditions and mold Owing to the drastic changes in the mold slag pool composition after casting high Al steel, the viscosity, heat transfer and performance of the mold flux is expected to be very different from the original one. To illustrate such changes, the equilibrium solidification, after reaction with the high Al steel (steady state), of the bottom slag layer (slag layer 1) and that of the average mold slag pool were calculated in Figs.…”

Section: Simulation Of Mold Flux Composition During Thesupporting

confidence: 79%

“…These reactions may cause significant compositional changes of the molten mold flux, which induce variations in mold flux properties and performance. This phenomenon was observed when casting high Al steels with conventional CaO-SiO 2 based mold fluxes, 2,3) resulting in a significant Al 2 O 3 accumulation (25 to 35 wt% Al 2 O 3 within 15 min 2,3) ) and SiO 2 reduction in the mold flux. In spite of their industrial importance, the phase equilibrium of fluorine containing oxide systems has not been well investigated due to the complexity of their chemistry and the difficulties in performing experiments.…”

Section: Introductionmentioning

confidence: 88%

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Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Ende

Jung

2014

ISIJ Int.

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A thermodynamic database for the oxyfluoride system CaO-MgO-Al2O3-SiO2-Na2O-K2O-Li2O-MnOFeO-F has been developed based on the critical evaluation and optimization of all available experimental thermodynamic and phase diagram data. The developed database can be used for phase diagram and equilibrium solidification calculations for multicomponent systems. Such accurate database with high predictability capability assists in understanding the crystallization behavior of mold fluxes. In addition, a kinetic model was developed to simulate the interactions between the mold flux and molten steel using effective equilibrium reaction volumes combined with the thermodynamic database. The kinetic model successfully reproduced the significant Al2O3 accumulation observed when casting high Al steel with CaO-SiO2 based mold flux. Equilibrium solidification calculation performed on the Al2O3-rich mold slag revealed detrimental changes in the solidification temperature, the primary phase and the evolution of the liquid fraction with temperature.KEY WORDS: continuous casting mold flux; thermodynamic database; equilibrium solidification behavior; kinetic model; steel/slag/inclusion reactions.

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Section: Simulation Of Mold Flux Composition During Thesupporting

confidence: 89%

Section: Simulation Of Mold Flux Composition During Thesupporting

confidence: 79%

Section: Introductionmentioning

confidence: 88%

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Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Ende

Jung

2014

ISIJ Int.

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“…High aluminum transformation induced plasticity steel (TRIP) is widely used in automobile due to its high strength, high ductility, and superior formability . 20Mn23AlV is a kind of nonmagnetic steel with wide application in manufacture of core material for transformers, and its Al content is between 1.5 and 2.5% . High aluminum electrical steels([Al] = 0.8–1.2%) were developed to provide the low core loss and high permeability required for electrical transformers .…”

Section: Introductionmentioning

confidence: 99%

Non‐Isothermal Crystallization Kinetics of Mold Fluxes Containing Li₂O for High Aluminum Steel Casting

Yang

Wen

Tang

2015

steel research int.

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When continuously casting high Al steels, CaO-SiO 2 based mold fluxes can be easier for sequence casting, but due to the significant reactions of the Al in the metal with SiO 2 , slab surface quality is not desirable. When increasing basicity of CaO-SiO 2 based mold fluxes, slab surface quality can be improved, but thick slag rim can easily be formed during cooling process. Therefore, non-isothermal crystallization kinetics of mold fluxes used for high Al steels are studied to optimize the crystallization behavior of "working" fluxes. Results indicate that the addition of Li 2 O can decrease crystallization temperature and crystallization rate within the range of Na 2 O studied. The Avrami exponent determined by Avrami equation indicates that disk-like growth type and spherulitic-like growth type are the main mechanisms in crystallization, which is consistent with results observed under SEM. When mold flux contains 8% Na 2 O and 4.5% Li 2 O, the effective activation energy is between À299 and À488 KJ mol À1 . When mold flux contains no Na 2 O and 6.5% Li 2 O, the effective activation energy is between À266 and À414 KJ mol À1 , which indicates that Na 2 Ofree mold fluxes containing high Li 2 O is beneficial for improving crystallization characteristics and realizing sufficient lubrication.

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“…The first way is that reactive CaO–SiO 2 based mould fluxes with low Al 2 O 3 content and low basicity is adopted and expected to form CaO–SiO 2 –Al 2 O 3 based mould fluxes after reaction whose property can meet the requirements of continuous casting process . Although sequence casting can be realized with the low basicity mould fluxes, yet slag–metal reaction is inevitable, and therefore, some quality problems, such as cracking, depression and deep oscillation mark on the slab surface cannot be solved perfectly . The second way is to use “non‐reactive” mould fluxes, CaO–Al 2 O 3 based mould fluxes with low SiO 2 content .…”

Section: Introductionmentioning

confidence: 99%

Development and Evaluation of CaO–SiO₂ Based Mould Fluxes for Casting High Aluminum TRIP Steel

Wen

Liu

et al. 2014

steel research int.

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Due to its high content in Al‐TRIP steel, Al is easily to react with SiO2 in mould fluxes during the continuous casting process, which results in the drastic decrease of SiO2 content, increase of Al2O3 content and the basicity (R = CaO/SiO2), respectively. The magnitude change of physical properties of the slag can affect continuous casting process and the surface quality of slabs. Especially, the change of basicity influenced the crystallization property, and thus influenced the heat transfer of mould fluxes. In this study, three CaO–SiO2 based mould fluxes A, B, and C with different basicity (A was the originally used mould fluxes, B and C were the newly developed mould fluxes) were used to cast high aluminum TRIP steel with 0.80–1.00% Al and 0.085–0.115% carbon. The property change of mould fluxes and its influence on the quality of the slab surface were evaluated. It is indicated that appropriate increase of the basicity of base mould fluxes was beneficial to improve the crystallization property of spent slag and for the inhibition of heat transfer so as to reduce the occurrence of cracking and depression on the slab surface effectively. And also, it can shorten the time of slag–metal reaction reaching dynamic equilibrium and the length of transition slab with defect on surface in the start casting stage. Accordingly, the quality of slab cast by mould fluxes C was the best.

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Behavior of Mold Slag Used for 20Mn23Al Nonmagnetic Steel During Casting

Cited by 45 publications

References 7 publications

Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Non‐Isothermal Crystallization Kinetics of Mold Fluxes Containing Li₂O for High Aluminum Steel Casting

Development and Evaluation of CaO–SiO₂ Based Mould Fluxes for Casting High Aluminum TRIP Steel

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Behavior of Mold Slag Used for 20Mn23Al Nonmagnetic Steel During Casting

Cited by 45 publications

References 7 publications

Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Development of a Thermodynamic Database for Mold Flux and Application to the Continuous Casting Process

Non‐Isothermal Crystallization Kinetics of Mold Fluxes Containing Li2O for High Aluminum Steel Casting

Development and Evaluation of CaO–SiO2 Based Mould Fluxes for Casting High Aluminum TRIP Steel

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Product

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Non‐Isothermal Crystallization Kinetics of Mold Fluxes Containing Li₂O for High Aluminum Steel Casting

Development and Evaluation of CaO–SiO₂ Based Mould Fluxes for Casting High Aluminum TRIP Steel