Liquidus Temperature of Mould Fluxes in Casting of Ti-stablized Stainless Steel

Shu, Qifeng; Wang, Zhen; Chou, Kuo‐Chih

doi:10.1515/htmp-2012-0063

Cited by 4 publications

(2 citation statements)

References 14 publications

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“…23,24) During heating of samples, several endothermic thermal effects could be investigated, and liquidus temperature could be obtained as the last endothermic peak temperature. 24) The undercooling for onset crystallization could be defined as ΔT=TL-Tx, where TL represents liquidus temperature and Tx represents onset crystallization temperature for one kind crystal. 22) The ΔT values of mould fluxes with different TiO2 content were calculated by employing liquidus temperature and crystallization temperature at the cooling rate of 25 K/min.…”

Section: Crystallization Behaviors Of Mould Fluxes Investigated By Dtmentioning

confidence: 99%

Effect of TiO2 Addition on Crystallization Characteristics of CaO-Al2O3-based Mould Fluxes for High Al Steel Casting

Shu

Hou

et al. 2015

ISIJ Int.

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Crystallization behaviors of new developed CaO-Al2O3 based mould fluxes with TiO2 addition for casting of high-Al steels were investigated by using DTA techniques combined with SEM-EDS and XRD analysis. XRD and SEM analyzed on the crystallized samples showed that the sequence of crystal precipitation for TiO2-free mould flux during cooling was MgO, and followed by Ca12Al14O33 during cooling. The sequence of crystal formation for TiO2-bearing mould fluxes during cooling is CaTiO3 to MgO, and then Ca12Al14O33. Continuous cooling transformation diagrams (CCT) were constructed for analysis of the crystallization behaviors. The Undercooling values for onset crystallization of various crystals were calculated by using liquidus temperature obtained by heating DTA and crystallization temperature of various crystals. The crystallization temperatures of CaO-Al2O3 based mould fluxes increased with increasing TiO2 content. The undercooling values for onset crystallization of CaTiO3 decreased with increasing TiO2 content, which indicating that the crystallization of CaTiO3 was enhanced with increasing TiO2 content. The undercooling values for onset crystallizations of Ca12Al14O33 and MgO only changed slightly with increasing TiO2. This indicated that crystallizations of Ca12Al14O33 and MgO crystals were only slightly influenced by TiO2 addition. The overall crystallization of mould fluxes was enhanced with increasing TiO2 content.

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Section: Crystallization Behaviors Of Mould Fluxes Investigated By Dtmentioning

confidence: 99%

Effect of TiO2 Addition on Crystallization Characteristics of CaO-Al2O3-based Mould Fluxes for High Al Steel Casting

Shu

Hou

et al. 2015

ISIJ Int.

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“…Besides the crystallization temperature, the liquidus temperature was also determined; it was obtained by considering the peak temperature for the last endothermic peak when heating the samples during DSC experiments. 14) The undercooling for onset crystallization (ΔT) is defined as the difference between liquidus temperature (T L ) and crystallization temperature (T C ) as follows: where T, T 0 and T e are the instantaneous, onset and end crystallization temperatures, respectively. The heat flow rate determined by DSC is represented by dH/dT.…”

Section: Dsc Analysismentioning

confidence: 99%

Non-Isothermal Melt Crystallization Kinetics for CaO–Al2O3–B2O3 F-Free Mould Fluxes

Shu

Klug

2019

ISIJ Int.

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Efforts have been made to develop fluorine-free mould fluxes for the continuous casting of steel process. In this work the crystallization behaviour of fluorine-free mould slags based on the CaO-Al 2 O 3-B 2 O 3 system was investigated by differential scanning calorimeter (DSC) and scanning electron microscopy equipped with energy dispersive spectroscopy(SEM-EDS). The crystallization kinetics for Ca 3 Al 2 O 6 primary crystals was analysed by combining modified Avrami analysis with Friedman isoconversional method. Avrami parameter n is close to 4 for samples with the ratios w(CaO)/w(Al 2 O 3) = 1 and w(CaO)/w(Al 2 O 3) = 1.2, indicating a crystallization mechanism of continuous bulk nucleation and 3D crystal growth. The Avrami parameter n for samples with w(CaO)/w(Al 2 O 3) = 0.9 is close to 3, indicating instantaneous bulk nucleation and 3D crystal growth. The crystallization rate constant is the highest and half crystallization time is the lowest for the samples with w(CaO)/w(Al 2 O 3) = 0.9, indicating the fastest crystallization. In the initial stage, effective activation energies were mainly determined by the undercooling values. In the final stage, kinetic barrier for crystallization could have some influence on crystallization; for the investigated mould fluxes crystallization in the final stage is retarded by increasing w(CaO)/w(Al 2 O 3) ratio. Thus crystallization mechanisms were elucidated and effective activation energy of crystallization for the first crystal which precipitates from melt was determined.

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Investigation the influences of B₂O₃and R₂O on the structure and crystallization behaviors of CaO–Al₂O₃based F-free mold flux

Kong

Gao

et al. 2018

Metall. Res. Technol.

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The influences of B2O3 and R2O on the structure and crystallization of CaO–Al2O3 based F-free mold flux were investigated by Raman Spectroscopy and Differential Scanning Calorimetry Technique, respectively, for developing a new type of F-free mold flux. The results of structural investigations showed that B3+ is mainly in the form of [BO3]. And [BO3] appears to form BIII–O–Al linkage which will produce a positive effect on forming [AlO4] network. The number of bridging oxygen and the degree of polymerization of [AlO4] network structure for CaO–Al2O3 system were also increased with the increasing of B2O3. On the contrary, with the addition of R2O into CaO–Al2O3–B2O3 system, the number of bridging oxygen and the degree of polymerization of [AlO4] network were decreased. DSC results showed that the crystallization process became more sluggish with the increase of B2O3, which indicated that the crystallization ability was weakened. While the quenched mold fluxes crystallized more rapidly when introducing R2O. In other word, the crystallization rates of CaO–Al2O3 based slags were accelerated by the introduction of R2O. The liquidus temperature and crystallization temperature were decreased with the increasing amount of B2O3 or by addition of R2O into CaO–Al2O3 system. Only one kind of crystal was precipitated in 8% B2O3 and %R2O-containing samples, which was CaAl2O4 identified by SEM-EDS. When the content of B2O3 increased from 8% to 16%, Ca3B2O6 is clearly observed, demonstrating that the crystallization ability of Ca3B2O6 is enhanced by the increasing concentration of B2O3 in mold flux. The Ca/Al ratio of the generated calcium aluminate has been altered from 1:2 to 1:4 with the increasing of B2O3. The size of CaAl2O4 crystal is gradually increased with the addition of R2O. The crystallization ability of CaAl2O4 is promoted by R2O.

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Liquidus Temperature of Mould Fluxes in Casting of Ti-stablized Stainless Steel

Cited by 4 publications

References 14 publications

Effect of TiO<sub>2</sub> Addition on Crystallization Characteristics of CaO-Al<sub>2</sub>O<sub>3</sub>-based Mould Fluxes for High Al Steel Casting

Effect of TiO<sub>2</sub> Addition on Crystallization Characteristics of CaO-Al<sub>2</sub>O<sub>3</sub>-based Mould Fluxes for High Al Steel Casting

Non-Isothermal Melt Crystallization Kinetics for CaO–Al<sub>2</sub>O<sub>3</sub>–B<sub>2</sub>O<sub>3</sub> F-Free Mould Fluxes

Investigation the influences of B₂O₃and R₂O on the structure and crystallization behaviors of CaO–Al₂O₃based F-free mold flux

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Liquidus Temperature of Mould Fluxes in Casting of Ti-stablized Stainless Steel

Cited by 4 publications

References 14 publications

Effect of TiO<sub>2</sub> Addition on Crystallization Characteristics of CaO-Al<sub>2</sub>O<sub>3</sub>-based Mould Fluxes for High Al Steel Casting

Effect of TiO<sub>2</sub> Addition on Crystallization Characteristics of CaO-Al<sub>2</sub>O<sub>3</sub>-based Mould Fluxes for High Al Steel Casting

Non-Isothermal Melt Crystallization Kinetics for CaO–Al<sub>2</sub>O<sub>3</sub>–B<sub>2</sub>O<sub>3</sub> F-Free Mould Fluxes

Investigation the influences of B2O3and R2O on the structure and crystallization behaviors of CaO–Al2O3based F-free mold flux

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Investigation the influences of B₂O₃and R₂O on the structure and crystallization behaviors of CaO–Al₂O₃based F-free mold flux