Coupling relationship between dephosphorisation and desulphurisation abilities or potentials for CaO–FeO–Fe2O3–Al2O3–P2O5 slags over a large variation range of slag oxidisation ability during secondary refining process of molten steel

2016 ◽  
Vol 45 (1) ◽  
pp. 25-43 ◽  
Author(s):  
X. M. Yang ◽  
J. Y. Li ◽  
M. Zhang ◽  
G. M. Chai ◽  
D. P. Duan ◽  
...  
Keyword(s):  
Molten Steel ◽  
Refining Process ◽  
Coupling Relationship ◽  
Secondary Refining ◽  
Variation Range

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

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.

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

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.

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

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1083 ◽  
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.

Effect of Slag-Metal Reaction on Transformation of Al2O3 inclusions in Pipeline Steel

2011 ◽  
Vol 284-286 ◽  
pp. 1143-1147
Author(s):  
Qiang Li ◽  
Xin Hua Wang ◽  
Hai Bo Li
Keyword(s):  
Molten Steel ◽  
Pipeline Steel ◽  
Refining Process ◽  
High Grade ◽  
Secondary Refining ◽  
Calcium Aluminates ◽  
Hydrogen Induced Cracking ◽  
Liquid Calcium ◽  
Calcium And Magnesium ◽  
Refining Time

For high grade pipeline steel, elimination of Al2O3 inclusions can improve the susceptibility of hydrogen-induced cracking (HIC) and stress corrosion cracking (SCC). In the present work, the transformation of Al2O3 inclusions with slag-metal reaction was studied by controlling ladle slag and relative technologies in LF-RH refining process. It is found that Al2O3 inclusions decrease with increasing refining time, and no pure Al2O3 inclusions exist in molten steel at the end of secondary refining; the remained inclusions in molten steel are liquid calcium aluminates and semi-liquid CaO-MgO-Al2O3 complex inclusions. The analysis of thermodynamic equilibrium proves that CaO and MgO in slag can be reduced by aluminum in molten steel, which is the source of calcium and magnesium in molten steel.

scholarly journals Factors to Determine Inclusion Compositions in Molten Steel during the Secondary Refining Process of Case-Hardening Steel

2016 ◽  
Vol 56 (11) ◽  
pp. 1973-1981 ◽  
Author(s):  
Takanori Yoshioka ◽  
Kenichiro Nakahata ◽  
Takanori Kawamura ◽  
Yasuhide Ohba
Keyword(s):  
Molten Steel ◽  
Refining Process ◽  
Case Hardening ◽  
Secondary Refining ◽  
Case Hardening Steel

Temperature Prediction Model for Molten Steel in RH Refining Process

2013 ◽  
Vol 712-715 ◽  
pp. 22-25 ◽  
Author(s):  
Tia Xia ◽  
Zhu He
Keyword(s):  
Mathematical Model ◽  
Prediction Model ◽  
Molten Steel ◽  
Initial Temperature ◽  
Refining Process ◽  
Temperature Prediction ◽  
Steel Temperature ◽  
Molten Steel Temperature

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.

Optimization of Pass Parameters on Two-Grooves Skew Rolling for Al Ball

2009 ◽  
Vol 419-420 ◽  
pp. 313-316 ◽  
Author(s):  
Xiao Min Shi ◽  
Bao Jian Wang ◽  
Zhen Hua Li
Keyword(s):  
Continuous Casting ◽  
Practical Experience ◽  
Refining Process ◽  
Steel Ball ◽  
Die Design ◽  
Secondary Refining ◽  
Skew Rolling

The optimization of pass parameters is an important step in skew rolling design. In order to meet the demands of secondary refining process in continuous casting, on the basis of the practical experience of two-groove skew rolling for steel ball, and by means of the theory of two-groove skew rolling design ,the optimization of two-groove pass parameter for Φ21.6 mm Aluminum ball, a kind of additive in secondary refining process, is realized. The optimized pass parameters are used in the rolling die design, and the corresponding experiments indicate that the projects of optimized pass parameters are feasible, and the efficiency of two-groove skew rolling is twice as large as that of one-groove.

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