Thermodynamic Properties of Inclusions Formed Aluminum-Titanium Deoxidation of Molten Steel

Titanium alloyed steel has been widely used as automobile sheet steels, thick plate steels, and also stainless steels to improve the mechanical and chemical properties of many grade steels. Since Ti has strong affinity with oxygen, Ti is normally alloyed after Al deoxidation to keep the high yield of Ti. Therefore, Al-Ti deoxidation is one of the common and important secondary refining processes. Although the chemical stability diagram for this system has been reported by many researchers, these diagrams are inconsistent significantly each other. In the present study, the stability region of Al2TiO5 oxide was measured by equilibrating Fe-Al-Ti alloy and Al2TiO5 pellet in Al2O3 crucible at 1873 K. However, inclusions in metal after equilibration were Ti-containing Al2O3 or Al-containing TiOx. The precise phase diagrams and related thermodynamic data for the Al2O3-TiOx-FeO system should be determined.     

大规格纯钛铸锭脱氧现象及对策

利用真空自耗电弧炉进行了大规格纯钛铸锭的工业生产,研究并分析Ф1040 mm大规格高氧含量纯钛铸锭的底部脱氧现象和氧元素均匀性的问题。纯钛铸锭底部脱氧的原因是海绵钛中的Mg与添加剂TiO₂在一次铸锭熔炼时反应引起的。采用真空自耗电弧炉对梯度加氧自耗电极进行两次熔炼,结果表明:通过梯度加氧的方式可以有效解决纯钛铸锭脱氧的问题,并显著改善纯钛铸锭氧元素成分均匀性,使生产出的Ф1040 mm高氧含量纯钛铸锭头部、尾部氧含量的偏差控制在0.011%范围内。     

高钛渣氧化焙烧热力学分析

通过高钛渣高温氧化焙烧试验,研究焙烧前后物相结构转变与化学组成变化,并对高温氧化焙烧过程中高钛渣各组分的化学行为进行热力学讨论。结果表明:在1 000℃条件下氧化焙烧,黑钛石相与锐钛矿大部分发生晶型结构变化,转变为金红石型TiO2。探索高钛渣氧化焙烧的热力学规律,为火法处理高钛渣提供理论依据,对于改造传统处理高钛渣工艺具有重要的意义。     

Thermodynamic Study of Titanium Oxycarbide

Titanium oxycarbide was synthesized through carbothermic reduction of TiO₂ and sintering of TiO and TiC. The combustion enthalpy and specific heat capacity of oxycarbide were measured by differential scanning calorimetry (DSC). The mixing enthalpy and Gibbs free energy of the reaction?0.5TiO + 0.5TiC = TiC_0.5O_0.5, consequently, was calculated based on the preceding measured data. The Gibbs free energy obtained was in good agreement with those results obtained by the equilibrium measurements.     

Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

Metallurgical and Materials Transactions B - Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 °C), where the metal...     

Ultimate Deoxidation Method of Titanium Utilizing Y/YOCl/YCl3 Equilibrium

Metallurgical and Materials Transactions B - Deoxidation methods of titanium (Ti) scrap and Ti powder have become increasingly important in recent years. Some rare earth (RE) metals with strong...     

Deoxidation Mechanism in Reduced Titanium Powder Prepared by Multistage Deep Reduction of TiO2

Metallurgical and Materials Transactions B - There are technical bottlenecks in the preparation of metallic titanium powder by conventional thermal reduction of TiO2 with calcium, magnesium, or...     

Thermodynamic Analysis of Desulfurization and Its Connection With Deoxidation and Temperature for SPHC in JISC During LF Refining Process

The thermodynamic characteristics of desulfurization reaction (CaO)+[S]=(CaS)+[O] is analyzed based on the detailed composition of liquid steel and slag of Steel Plate Hot Commercial (SPHC) in Jiuquan Iron & Steel Corporation(JISC), where the activities of CaO, CaS and Al2O3 in molten slag are calculated by thermodynamic software FactSage for a more accurate result. The critical values of [O%]/[S%] for desulfurization at different temperature is are obtained, typically 0.09 at 1873K, which shows directly that it should deoxidize adequately for obtaining a favorable desulfurization condition. In addition, the thermodynamic analysis indicates that the actual dissolved O is much higher than that of equilibrium calculation which shows Al-O reaction in LF is far away from equilibrium, but it is perfect agreement with the computing results when taking the activity of Al2O3 as 1 that due to the inclusion component in LF is mainly Al2O3. Besides, with the temperature rise, the sulfur partition ratio increases softly meanwhile the reaction between Al and O is limited to a great degree resulting in the increase a dissolved oxygen in liquid steel that decreases the sulfur partition ratio seriously. As a result, the sulfur partition ratio appears to decrease with temperature increase in Al killed steel.     

Thermodynamic Modeling of Deoxidation Products and Inclusion Chemistry in Mn/Si Killed Tire-Cord Steel

The present work deals with thermodynamic modeling of oxide systems, in the context of slags and inclusions in steelmaking. The work has emphasis on oxides encountered during the production of tire – cord steel. Control of inclusion chemistry and variation in eutectic temperature and eutectic composition of MnO-Al2O3-SiO2 slag system have been studied, using Thermo-CalcR software. Relatively low liquidus temperatures are obtained for ratio of MnO / SiO2 = 0.5 - 1.5 and Al2O3 content from 10 - 20 mass%. It has been observed that the addition of Alumina leads to further increase in the liquidus temperature. The stability of inclusions is analyzed in terms of free energy values of related slag systems; and an appropriate minimum of Gibbs free energy value of slag phase observed at around 50 ppm of Oxygen. The observations could not be verified using thermodynamic experiments, but have been compared with findings in the open literature.     

Formation of Titanium Sulfide from Titanium Oxycarbonitride by CS2 Gas

Metallurgical and Materials Transactions B - Previously this group reported that a good quality titanium metal powder can be produced from titanium sulfides by electrochemical OS process. In this...     

含钛超纯铁素体不锈钢的铝脱氧及钙处理实验研究

通过500 kg真空感应炉对0.007%～0.015%C-15.96%～16.94%Cr-0.08%～0.36%Ti-0.015%～0.124%Al铁索体不锈钢的铝脱氧和钙处理实验,以及相应的热力学计算,对Al、Ti竞争氧化及夹杂物改性进行了研究.结果表明,当[Ti]/[Al]低于2.50时,氧化物夹杂主要为Al2O3,随[Ti]/[Al]的增加,钢中的主要夹杂由Al2O3向MgO-Al2O3-TiOx及Al2O3-TiOx转变,夹杂物平均尺寸逐步减小;钙处理后随[Ca]/[Al](0.01～0.08)的升高,钢中含钙复合夹杂的数量比例增加;包裹形复合夹杂的中心为氧化物,周边为TiN或Ti(CN).     

Thermodynamic Consideration of the Removal of Iron from Titanium Ore by Selective Chlorination

Thermodynamic study of the chlorination reactions of oxides such as titanium oxides and iron oxides at elevated temperatures was carried out in order to consider the removal of iron from titanium ore using selective chlorination method. In particular, various chlorination reactions were analyzed by utilizing chemical potential diagrams, and the applicability and usefulness of this thermodynamic study for analyzing the selective chlorination of titanium ore were demonstrated. Furthermore, chlorination reactions using various types of chlorinating agents were discussed from different viewpoints. It was shown that the selective chlorination of iron from titanium ore by HCl gas is thermodynamically feasible and efficient for upgrading titanium ore. Further, thermodynamic analysis showed that under certain conditions, TiCl₄ can be used as a chlorinating agent for the iron in the ore, and iron can be removed by evaporation directly from the ore as chloride gas. The results presented in this study provide useful information for developing a process for upgrading low-grade titanium ore for use as a titanium smelting feed through a dry method.     

含钛低碳钢凝固过程中氧化钛形成的热力学

通过研究含钛低碳钢的热力学,确定了在凝固过程中形成氧化钛的最佳钢液条件。计算结果表明：在含钛低碳钢中,为促进凝固初期析出Ti2O3从而细化凝固组织,关键的工艺要点是控制钢液中氧含量在0．0005％～0．0030％,铝含量小于0．001％,氮含量小于0．014％。     

Thermodynamic Properties and Mixing Thermodynamic Parameter of Binary Metallic Melt Involving Compound Formation

Massactionlaw,formulatedbyGuldbergand Waagein1864,showsthattheequilibriumconstant (ΔGθ)ofachemicalreactionisafunctionoftemper atureonly,andindependentfromtheconcentration ofreactantsandproducts.Itisanimportantsubject forallmonographsinthefieldofmetallu…     

Deoxidation of rimming steel in the ladle

Magnitogorsk Metallurgical Combine. Translated from Metallurg, No. 1, pp. 27, January, 1991.     

Thermodynamic Analysis of Formation of Fluoride from Gangue in Bayan Obo Iron Concentrate Containing Fluorite

In order to fill up the deficiency of the theoretical basis about fluoride formation during Bayan Obo iron concentrate roasting process,the thermodynamic conditions of the interactivity between the components of the gangue and calcium fluorite were studied by means of thermodynamic calculation,DTA-TG thermal analysis and XRD characterization.The results revealed that KF,NaF and SiF4(gaseous)could be formed during the roasting process,and the tendency of the generation of KF is greater than that of NaF or SiF4 in standard state.Besides,the results of roasting experiments showed that the products of KCaCO3 F and KCaF3 formed in the temperature range of 800-1 250℃and KF appears when the roasting temperature was higher than 1 250 ℃in K2O-CaF2 system.For the Na2O-CaF2 system,the product of NaF appears at temperature higher than 1 050 ℃.The formation reaction of gaseous SiF4 with solid phase CaO·SiO2in SiO2-CaF2 system took place only at temperature higher than 1 150℃.In the natural potash feldspar-CaF2-CaO system,the fluorination reaction products involved KF at temperature higher than 1 270℃,while in the natural aegirine-CaF2-CaO system,NaF formed at temperature higher than 980℃ during roasting process.     

Analysis of Rare-Earth Phase in a W-Mo-Ni-Fe-Mn-La Heavy Alloy

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