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.

A Thermodynamic Model for Evaluation of Mass Action Concentrations of La2O3-Al2O3-CaF2-CaO-MgO Slags for Electroslag Remelting Based on the Ion and Molecule Coexistence Theory

2013 ◽  
Vol 32 (6) ◽  
pp. 541-550 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Jun Tian
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Mass Fraction ◽  
Electroslag Remelting ◽  
Mass Action ◽  
Coexistence Theory ◽  
Maximum Value ◽  
Mass Action Concentration ◽  
Increasing Temperature ◽  
Good Agreement

AbstractAccording to the ion and molecule coexistence theory (IMCT) for molten slags and corresponding phase diagrams, a thermodynamic model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for La2O3-Al2O3, La2O3-Al2O3-CaF2, La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems for electroslag remelting (ESR) has been formulated. The influencing factors for the mass action concentration of La2O3, such as mass fraction of Al2O3, CaF2, CaO and MgO and temperature, were investigated. The results show that when the mole fraction of La2O3 is at 0.495, the mass action concentration of La2O3 · Al2O3 achieves its maximum value 0.946 in the La2O3-Al2O3 binary slag. In a composition area of La2O3: 10wt% ∼ 45wt%, Al2O3: 0wt% ∼ 50wt% and CaF2: 20wt% ∼ 70wt% of the La2O3-Al2O3-CaF2 ternary slag at 1873 K, the results show that the calculated values of NLa2O3 are in good agreement with the reported measured values of aLa2O3. The iso-curves of NLa2O3 is also drawn from the calculated results, which reveals that the mass action concentration of La2O3 decreases with the increasing of the Al2O3 and CaF2 content, and Al2O3 is stronger than CaF2 in decreasing the mass action concentration of La2O3. However, in La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems, the mass action concentration of La2O3 increases with the increasing of the MgO and CaO content, and CaO is stronger than MgO in increasing the mass action concentration of La2O3. In addition, the mass action concentration of La2O3 increases with the increasing temperature at the composition of 30wt%La2O3, 10wt%Al2O3, 40wt%CaF2, 10wt%MgO and 10wt%CaO.

The Thermal Diffusivity of Mg-Al-Sr and Mg-Al-Ca-Sr Sand Casting Magnesium Alloys

2012 ◽  
Vol 326-328 ◽  
pp. 249-254
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń ◽  
Grzegorz Moskal
Keyword(s):  
Thermal Diffusivity ◽  
Chemical Composition ◽  
Magnesium Alloys ◽  
Volume Fraction ◽  
Intermetallic Phases ◽  
Sand Casting ◽  
Al Alloy ◽  
Temperature Dependent ◽  
Total Volume Fraction ◽  
Increasing Temperature

In the present study, the thermal diffusivity of four sand casting magnesium alloys: Mg-9Al-1Zn, Mg-6Al-2Sr, Mg-9Al-1.5Ca-0.3Sr and Mg-9Al-2.2Ca-0.8Sr were studied. Sand casting was performed at 730-780°C temperatures. Thermal diffusivity was measured by a LFA 427 Netzsch apparatus. The thermal diffusivity of the investigated alloys was chemical composition and temperature dependent and increased with increasing temperature. The thermal diffusivity of Mg-Al-Ca-Sr alloys was higher than that of Mg-Al alloy, because the total volume fraction of intermetallic phases in alloys containing calcium and strontium is larger than that in Mg-Al alloy. The formation of intermetallic phases caused the consumption of the solute element in the α-Mg matrix, and improved the thermal diffusivity of the Mg-Al-Ca-Sr magnesium alloy.

Calculation Model of Mass Action Concentrations for CaO-MnO-FeO-SiO2-MgO-Al2O3 Slags Based on the Ion and Molecule Coexistence Theory

2012 ◽  
Vol 476-478 ◽  
pp. 134-138
Author(s):  
Xiao Hong Yang ◽  
Xiao Chun Ma ◽  
Cheng Chuan Wu ◽  
Guo Guang Cheng
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Slag System ◽  
Calculation Model ◽  
Mass Action ◽  
Structural Units ◽  
Coexistence Theory ◽  
Slag Structure ◽  
Calculation Results ◽  
Good Agreement

According to the ion and molecule coexistence theory (IMCT) of slag structure and corresponding phase diagrams, a thermodynamic model for calculating mass action concentrations of structural units or ion couples of CaO-MnO-FeO-SiO2-MgO-Al2O3 slags was established. Equilibrium mass action concentrations of each structure unit were gained. And the calculation results of NFeO and NMnO were compared with measured aFeO and aMnO. The comparison shows that the calculated values of NFeO and NMnO are in good agreement with the reported measured values of aFeO and aMnO, so this calculating model could fairly describe the characteristics of the slag system.

A Thermodynamic Model for Evaluation of Mass Action Concentrations of Ce2O3-contained Slag Systems Based on the Ion and Molecule Coexistence Theory

2013 ◽  
Vol 32 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Hu Long ◽  
Xiaohong Yang
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Mass Fraction ◽  
Aluminum Content ◽  
Mass Action ◽  
Coexistence Theory ◽  
Cerium Content ◽  
Maximum Value ◽  
Mass Action Concentration ◽  
Good Agreement

AbstractAccording to the ion and molecule coexistence theory (IMCT) for molten slags and corresponding phase diagrams, a thermodynamic model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for Ce2O3-Al2O3, CaO-Al2O3-Ce2O3 and CaO-Al2O3-SiO2-Ce2O3 slag systems has been formulated. The results show that when the mole fraction of Ce2O3 is at 0.49 in the binary slag, the mass action concentration of Ce2O3·Al2O3 achieves its maximum value 0.90. In a composition area of CaO/Al2O3 (mass fraction ratio) from 0.7 to 1.5 and Ce2O3 content (mass fraction) from 0 to 45% of the ternary slag at 1773 K, the results show that trends of calculated NAl2O3 are in good agreement with reported measured trends of aAl2O3. The iso-curves of NCe2O3 and NCaO are also drawn from the calculated results. A thermodynamic model of the equilibrium between 55.83%CaO-23%Al2O3-11.17%SiO2-10%Ce2O3 quaternary slag and molten steel containing aluminum has been further discussed. Results indicate that certain content of Ce would be dissolved in steel, which increases with the increasing of temperature and aluminum content, and when the aluminum content is 0.02%, the corresponding cerium content is in the range of 1.87 to 13.30 ppm at 1873 K. In summary, using Ce2O3 to replace Al2O3 can effectively reduce NAl2O3, certain content of Ce can dissolved in steel.

scholarly journals Dynamic axial contact stiffness analysis of position preloaded ball screw mechanism

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401881928 ◽  
Author(s):  
Jun Liu ◽  
Yi Ou
Keyword(s):  
Axial Load ◽  
Contact Stiffness ◽  
Dynamic Contact ◽  
Ball Screw ◽  
Coupling Relationship ◽  
Stiffness Model ◽  
Static Contact ◽  
Variation Range ◽  
Screw Mechanism ◽  
Feed Drive System

This article establishes an axial contact stiffness model of position preloaded ball screw mechanism based on Hertz contact theory. The analysis of dynamic axial contact stiffness is one of the foundations of the research on the dynamic characteristic of the ball screw feed drive system. The model takes into account the coupling relationship between the contact angle and the normal contact force, as well as the coupling relationship between the elastic deformation and the contact deformation coefficient. The static and dynamic axial contact stiffness characteristics of the preloaded ball screw mechanism are studied. The numerical analysis result shows that the static contact stiffness of the preloaded ball screw mechanism increases with the increase in the preload and decreases with the increase in the axial load. The dynamic contact stiffness of the preloaded ball screw mechanism increases with the increase in the screw’s rotational speed. The variation range of dynamic contact stiffness increases with the increase in axial load under the same preload. And the variation range of dynamic contact stiffness decreases with the increase in preload under the same axial load. The axial contact stiffness model established in this article can be used to analyze either static or dynamic contact stiffness of position preloaded ball screw mechanism.

Effect of Secondary Vacuum Treatment on Performance Characteristics of A516 Grade 65 Carbon Steel

2017 ◽  
Vol 1143 ◽  
pp. 38-44
Author(s):  
Anisoara Ciocan ◽  
Beatrice Tudor
Keyword(s):  
Chemical Composition ◽  
Vacuum Treatment ◽  
Vacuum Arc ◽  
Clean Steel ◽  
Composition Control ◽  
Steel Making ◽  
Secondary Refining ◽  
Metallic Inclusions ◽  
Before And After ◽  
Oil Gas

The purpose of this research is to analyze the making technology of clean steel used in the oil, gas and petrochemical industry. The steel was obtained into conventional electric arc furnace. To enhance the steel quality a secondary refining treatment was applied. The purity characteristics of the steel A516 Grade 65, before and after the treatment in the vacuum arc degassing equipment are discussed and compared. The deoxidation, desulphurisation in the presence of basic slag and degassing by injecting an inert gas and also by vacuum exposure are effective in reducing non-metallic inclusions and for chemical composition control. Data from 31 melts obtained in two industrial conditions are presented according to steel making parameters. The variation of chemical composition, especially of content of S, P, and the cleanliness of the steel in terms of content of non-metallic inclusions are analyzed.

Sign in / Sign up

Export Citation Format

Share Document