Crystallization Control for Fluorine-free Mold Fluxes: Effect of Na&lt;sub&gt;2&lt;/sub&gt;O Content on Non-isothermal Melt Crystallization Kinetics

Shu, Qifeng; Klug, Jeferson Leandro; Medeiros, Samuel Lucas Santos; Heck, Nestor Cezar; Liu, Yang

doi:10.2355/isijinternational.isijint-2020-132

Cited by 14 publications

(11 citation statements)

References 35 publications

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“…Through Figure 10, the effective activation energy E a was calculated from the slope of the fitting lines, which was 153.59, 198.92, 65.87, and 44.76 kJ mol −1 , respectively. The positive effective activation energies indicate that mold flux melt crystallization should be controlled by the diffusion process, [ 39 ] and a higher value of it represents a higher driving force. Therefore, a small amount of Cr 2 O 3 accelerates the crystallization, but the speed of crystallization becomes slower when Cr 2 O 3 continues to be added.…”

Section: Resultsmentioning

confidence: 99%

“…Through Figure 10, the effective activation energy E a was calculated from the slope of the fitting lines, which was 153.59, 198.92, 65.87, and 44.76 kJ mol À1 , respectively. The positive effective activation energies indicate that mold flux melt crystallization should be controlled by the diffusion process, [39] and a higher value of it represents a higher driving force. Therefore, a small As shown in Table 3, the Avrami index n represents the growth pattern of slag crystallization in some respects combined with the SHTT experimental pictures to analyze the Avrami index n. When n is greater than 1.5, the crystalline growth mode is dominated by 3D growth; when n is slightly less than 1.5, the crystalline growth mode is dominated by 1D growth; when n is around 1, the crystalline growth mode is dominated by 2D growth.…”

Section: Crystallization Characteristics Of Slag At the Isothermal Co...mentioning

confidence: 99%

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Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Chen

Wang

et al. 2023

steel research int.

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Herein, the effect of Cr2O3 on the crystallization and flow behavior of CaO–SiO2–Al2O3–Na2O–CaF2 continuous casting mold slags is investigated. The viscosity in the slag at 1200–1500 °C is measured by the rotating cylinder method and a quantitative relationship between the viscosity and the Raman structure Q3/Q2 is constructed. The time–temperature–transformation and continuous cooling transformation diagrams for various slags are obtained using a single hot‐thermocouple technique. The results show that with the crystallization temperature decreases, it can be observed that the crystal growth mode gradually changes from 3D spherical and 2D massive to 1D needle‐like. The study finds the transition from network modifier to network forming agent in the slag for Cr2O3 content from 0 to 3 wt%. The Cr2O3 added to 1–2 wt% decreases the viscosity and promotes crystallization. The viscosity increases and the crystallization is inhibited when the content of Cr2O3 increases to 3 wt%. Meanwhile, when Cr2O3 is added to 3 wt%, the Cr2O3 crystalline phase precipitates except for the main crystalline phase 2CaO·SiO2.

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Section: Resultsmentioning

confidence: 99%

Section: Crystallization Characteristics Of Slag At the Isothermal Co...mentioning

confidence: 99%

Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Chen

Wang

et al. 2023

steel research int.

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Section: Introductionmentioning

confidence: 99%

“…In this context, it is known from the literature [10,11] that differential scanning calorimetry (DSC) is a powerful technique for studying phase transformations in steels and alloy materials. In addition, the DSC technique can perform non-isothermal measurements [11]. Under this circumstance, the effective activation energy of a phase transformation fraction can be determined by isoconversional methods without assuming the kinetic-model function (model-free) [12,13].…”

Section: Introductionmentioning

confidence: 99%

Recrystallisation kinetics and yield-strength adjustment after annealing of cold-rolled microalloyed steel

Leão

Medeiros

Saraiva

et al. 2022

Materials Science and Technology

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After continuous annealing process (CAP) at 790°C, 85% of the coils of 50% cold-rolled low carbon microalloyed (LCM) steel did not exhibit yield-strength (YS) on the target range, while the 70% cold-reduced LCM coils did. In this context, the non-isothermal recrystallisation kinetics of ferrite for the above two full-hard LCM steel were investigated using differential scanning calorimetry and the Friedman differential isoconversional method. The recrystallisation kinetics of ferrite for the two deformed states showed different behaviour. Regarding a fixed degree of cold-rolling deformation, the soaking temperature was found as the manageable parameter to control YS during CAP. Consequently, a suitable YS of the 50% cold-rolled LCM steel was achieved by setting the soaking temperature at 773°C.

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“…[13] Furthermore, it was found that with the addition of Na 2 O, the incubation time was reduced and the crystallization tendency increased. [14,15] Shu et al [16] investigated the effect of the Na 2 O content on nonisothermal crystallization kinetics to adjust the crystalline fraction in fluorine-free CaO-Al 2 O 3 -SiO 2 -based mold slags with respect to the continuous casting of peritectic steels. It was shown that an increase in the Na 2 O content enhanced crystallization due to the depolymerization of the slag structure and decreased the effective activation energy for nonisothermal crystallization.…”

Section: Introductionmentioning

confidence: 99%

New Mold Slag Compositions for the Continuous Casting of Soft Steels

Kölbl

2021

steel research int.

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Several fluorine‐free mold slag compositions have already been established in the literature. In all cases, the formation of a crystalline phase exhibiting behavior similar to that of cuspidine is emphasized to control horizontal heat transfer without influencing the lubrication performance for the casting of peritectic steel grades. In contrast, for casting soft steels, glassy solidification of the slag is required. Herein, different slag compositions involving the selected oxides are developed with the help of FactSage calculations. Mixtures of pure raw materials are melted at 1673 K and quenched to 295 K. It is observed that B2O3 increases the glass‐forming ability of the slags. To obtain the glassy phase, the composition must satisfy the conditions and . For TiO2 content <10 wt%, glassy solidification is detected after quenching to room temperature. However, this phenomenon‐is not observed for slags with TiO2 content >15 wt%. Moreover, the addition of alumina and alkali oxides enhances crystallization. Based on these findings, promising mold slag compositions are designed and characterized in the laboratory using a furnace crystallization test, mineralogical investigations, and the single/double hot thermocouple technique. From the investigated mixtures, three compositions are suggested for use in continuous casting processes.

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Crystallization Control for Fluorine-free Mold Fluxes: Effect of Na<sub>2</sub>O Content on Non-isothermal Melt Crystallization Kinetics

Cited by 14 publications

References 35 publications

Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Recrystallisation kinetics and yield-strength adjustment after annealing of cold-rolled microalloyed steel

New Mold Slag Compositions for the Continuous Casting of Soft Steels

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Crystallization Control for Fluorine-free Mold Fluxes: Effect of Na<sub>2</sub>O Content on Non-isothermal Melt Crystallization Kinetics

Cited by 14 publications

References 35 publications

Effect of Cr2O3 Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Effect of Cr2O3 Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Recrystallisation kinetics and yield-strength adjustment after annealing of cold-rolled microalloyed steel

New Mold Slag Compositions for the Continuous Casting of Soft Steels

Contact Info

Product

Resources

About

Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Effect of Cr₂O₃ Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag