Prediction model of sulphur distribution ratio between CaO–FeO–Fe2O3–Al2O3–P2O5slags and liquid iron over large variation range of oxygen potential during secondary refining process of molten steel based on ion and molecule coexistence theory

A mathematical model for the RH refining process was developed and validated by the measured molten steel temperature in situ. It is showed that the model predicted temperature matched the measured value well and the average errors within ±5°C were 86.9%. The model results also showed that for every increase of 100°C of the initial temperature of the chamber inwall , the average molten steel temperature increased by about 8°C. For every blowing extra 50m3 oxygen, the steel temperature increased by about 7°C.

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Effect of [Al]s, [Mg], [Ca] in Molten Steel on Inclusion Content for High Speed Wheel Steel during LF-VD Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.898.60 ◽

2014 ◽

Vol 898 ◽

pp. 60-63

Author(s):

Yu Tang

Keyword(s):

Fatigue Life ◽

Molten Steel ◽

High Speed ◽

Refining Process ◽

Fatigue Performance ◽

Wheel Steel ◽

Inclusion Content ◽

High Basicity ◽

Secondary Refining ◽

Improve Fatigue

In order to improve fatigue life of wheel steel, LF-VD secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. Inclusion content would be influenced by [Al]s, [Mg], [Ca] in molten steel. It is found that Al2O3 inclusions, which are the products of Al-deoxidation, would react with [Mg], [Ca] in molten steel to transform into CaO-MgO-Al2O3 complex inclusions, which is the key for the enhancement of fatigue performance for wheel steel.

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Effect of Slag Composition on [Mg], [Ca] Content in Molten Steel for High Speed Wheel Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.746.501 ◽

2013 ◽

Vol 746 ◽

pp. 501-504

Author(s):

Tang Yu

Keyword(s):

Molten Steel ◽

Slag Composition ◽

High Speed ◽

Refining Process ◽

Wheel Steel ◽

Complex Inclusion ◽

High Basicity ◽

Secondary Refining ◽

Positive Factor ◽

Improve Fatigue

In order to improve fatigue life of wheel steel, secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. [M, [C content in molten steel would be influenced by slag composition. It is found that high basicity, high Al2O3 content and low oxidizing property is positive factor for proper [M, [C content in molten steel which is the key of inclusion transformation from Al2O3 to CaO-MgO-Al2O3 complex inclusion, contributing to the enhancement of fatigue performance for wheel steel.

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Thermodynamic Model of Calculation of Sulfur Distribution Ratio between B2O3-Containing Slag and Molten Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.633-634.188 ◽

2014 ◽

Vol 633-634 ◽

pp. 188-191

Author(s):

Xiang Zhu ◽

Yang Li ◽

Xiao Jian Fan ◽

Hong Ming Wang ◽

Gui Rong Li

Keyword(s):

Molten Steel ◽

Distribution Ratio ◽

Thermodynamic Model ◽

Slag Basicity ◽

Sulfur Distribution ◽

Coexistence Theory ◽

Sulfur Distribution Ratio

A thermodynamic model of calculation of sulfur distribution ratio between B2O3-containing slag and molten steel has been developed on the basis of the ion and molecule coexistence theory. Based on the model, the effects of B2O3 content and slag basicity on the sulfur distribution ratio in 1873K were investigated respectively. The results indicate that the sulfur distribution ratio decreased with increasing the content of B2O3, and when the content of B2O3 exceeds 6%, the sulfur distribution ratio was lower than 2.0. Therefore, in order to ensure the desulphurization ability of slag, the content of B2O3 should be controlled at about 6%. Moreover the sulfur distribution ratio can be increased by increasing the slag basicity.

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A Further Evaluation of the Coupling Relationship between Dephosphorization and Desulfurization Abilities or Potentials for CaO-based Slags: Influence of Slag Chemical Composition

Metals ◽

10.3390/met8121083 ◽

2018 ◽

Vol 8 (12) ◽

pp. 1083 ◽

Cited By ~ 5

Author(s):

Xue-min Yang ◽

Jin-yan Li ◽

Meng Zhang ◽

Fang-jia Yan ◽

Dong-ping Duan ◽

...

Keyword(s):

Chemical Composition ◽

Sulfide Capacity ◽

Mass Action ◽

Basic Oxide ◽

Coexistence Theory ◽

Coupling Relationship ◽

Phosphate Capacity ◽

Secondary Refining ◽

Variation Range ◽

Increasing Temperature

The coupling relationships between dephosphorization and desulfurization abilities or potentials for CaO–FeO–Fe2O3–Al2O3–P2O5 slags over a large variation range of slag oxidization ability during the secondary refining process of molten steel have been proposed by the present authors as logLp + 5logLs or logCpo3-4 + logCs2- in the reducing zone and as logLp + logLs - 5logNFetO or logCPO3-4 + logCs2- in the oxidizing zone based on the ion and molecule coexistence theory (IMCT). In order to further verify the validation and feasibility of the proposed coupling relationships, the effects of chemical composition of the CaO-based slags are provided. The chemical composition of slags was described by three group parameters including reaction abilities of components represented by the mass action concentrations Ni , two kinds of slag basicity as simplified complex basicity and optical basicity , and the comprehensive effect of iron oxides FetO and basic oxide CaO. Comparing with the strong effects of chemical composition of the CaO-based slags on dephosphorization and desulfurization abilities or potentials, the proposed coupling relationships have been confirmed to not only be independent of slag oxidization ability as expected but also irrelevant to the aforementioned three groups of parameters for representing the chemical composition of the CaO-based slags. Increasing temperature from 1811 to 1927 K (1538 to 1654 °C) can result in a decreasing tendency of the proposed coupling relationships. In terms of the proposed coupling relationships, chemical composition of slags or fluxes with assigned dephosphorization ability or potential can be theoretically designed or optimized from its desulfurization ability or potential, and vice versa. Considering the large difference of magnitude between phosphate capacity CPO3-4 and sulfide capacity CS2- , the proposed coupling relationships between dephosphorization and desulfurization abilities for CaO-based slags are recommended to design or optimize chemical composition of slags.

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