应用钢液定氧技术优化脱氧工艺

对40t转炉脱氧工艺作了系统研究,通过测定钢液氧含量变化,查清了脱氧后钢中游离氧含量水平,找出了影响氧含量变化规律的因素。定量地评价了转炉冶炼操作,为冶炼控制钢中氧含量指出了方向,优化了以钢液氧活度为依据的脱氧操作制度。     

对钢水深脱氧及钢水可浇性能的分析

在UHP－EAF－LF－CCM生产线上,为降低钢中氧含量,对钢水用铝深脱氧,并中脱氧产物Al2O3进行变形处理,改善钢水可浇性。     

Nucleation and growth kinetics of inclusions during liquid steel deoxidation

Abstract

The phenomenon of solid inclusion nucleation and growth during the liquid steel deoxidation process is studied numerically. It is shown that the diffusion of atoms, the Ostwald ripening effect, and Brownian movement together control the growth of small size particles. It appears that this stage of initial precipitation lasts for only about 10 s. When the particle diameter exceeds a threshold of ~1 μm, the growth process becomes dominated by particle collisions and agglomeration. The efficiency of these mechanisms depends on the particle size distribution as produced during growth. Comprehensive evaluations are still impeded by the limited capacity of computers at present.     

Review of oxygen sensors for use in steelmaking and of deoxidation equilibria

Abstract

Oxygen galvanic cells developed by a number of investigators for use at steelmaking temperatures are discussed. A design feature common to most of the oxygen sensors developed for use in steelmaking is based on the use of a lime stabilized zirconia pellet sealed into one end of a narrow silica or other refractory tube. The major difference in the sensors developed is in the choice of the oxygen reference electrode. Available data indicate that the solid reference electrode, e.g., Cr-Cr₂O₃, offers advantages over the gas reference electrodes. Some deoxidation equilibria redetermined using the oxygen galvanic cell are reviewed. An account is given of reaction equilibria for deoxidation by silicon, manganese and other deoxidizers of interest to steelmaking.

Résumé

Dans cet article les auteurs passent en revue les divers types de piles galvaniques dévelopées par de nombreux chercheurs pour l'utilisation en sidérurgie.

Un point commun des sondes utilisées dans l'aciérie est l'utilisation d'une pastille de zircone stabilisée à la chaux scellée à une extrémité d'un etroit tube de silice ou d'un autre réfractaire. La différence majeure dans les sondes développées réside dans le choix de l'electrode de référence. Des données valables indiquent que l'electrode de référence solide (par exemple Cr-Cr₂O₃), offre plus d'avantages que les électrodes de référence gazeuses. Un calcul est donné pour des réactions de désoxydation par le silicium, le managanése et d'autres éléments oxydants utilisés en sidérurgie.     

Electrochemical control of oxygen and physicochemical analysis of the deoxidation of 08cr18ni10t steel in a ladle

The thermodynamic and kinetic laws of the deoxidation of 08Cr18Ni10T steel in the ladle of an AVOS plant are studied using experimental heats.     

脱氧工艺对车轮钢氧化物夹杂控制的影响

从脱氧材料的选择、加入时间和加入方式以及脱氧产物排除方法试验了不同脱氧工艺对车轮钢中氧化物夹杂控制的影响,试验结果表明:采用出钢预脱氧+LF一次性加Al+钙处理工艺,能有效降低钢中B类夹杂,可完全满足车轮钢对B类夹杂物的技术条件要求。     

Improvement in the deoxidation of wheel steel

Vyksa Metallurgical Plant. Institute of Ferrous Metallurgy. Translated from Metallurg, No. 12, p. 39, December, 1990     

The deoxidation thermodynamics of cerium and lanthanum in liquid iron

The deoxidation thermodynamics of the Fe?Ce?O and Fe?La?O systems are estimated by combining the free energies of solution of cerium and lanthanum in iron, obtained from the respective phase diagrams, with the standard free energies of formation of cerium and lanthanum oxides given in the literature. Values for the deoxidation constants (w/o Ce)²·(w/o O)³ and (w/o La)²·(w/o O)³ of about 1×10^?20 are predicted at steelmaking temperatures. These predicted values are much lower than those obtained experimentally. It is suggested that refractory interactions, and sampling and analytical difficulties, in both laboratory and industrial determinations of these deoxidation constants, lead to erroneously high results.     

Inclusion control of ferritic stainless steel by aluminum deoxidation and calcium treatment

A thermodynamic equilibrium between aluminum and oxygen and inclusion morphology in the Fe-16Cr stainless steel were investigated to understand the fundamentals of the aluminum deoxidation technology for ferritic stainless steels. Further, the effect of calcium addition on the changes in chemistry and morphology of inclusions was discussed. The measured results for the aluminum-oxygen equilibria exhibit relatively good agreement with the calculated values, indicating that an introduction of the first-and second-order interaction parameters, recently reported, is reasonable to numerically express the aluminum deoxidation equilibrium in a ferritic stainless steel. In the composition of dissolved aluminum content greater than about 60 ppm, pure alumina particles were observed, while the alumino-manganese silicates containing Cr₂O₃ appeared at less than 20 mass ppm of dissolved aluminum. The formation of calcium aluminate inclusions after Ca treatment can be discussed based on the thermodynamic equilibria among calcium, aluminum, and oxygen in the steel melt. In the composition of steel melt with relatively high content of calcium and low aluminum, the log ( ) of inclusions linearly increases by increasing the log [a _Ca/a _Al ² ·a _O ² ] with the slope close to unity. However, the slope of the line is significantly lower than the expected value in the composition of steel melt with relatively low calcium and high aluminum contents.     

GA-BP渣系活度预测模型及不锈钢脱氧机理

采用GA-BP神经网络模型对熔渣组元活度进行预测,通过对不同温度条件下不同组元渣系活度值的验证,证明了GA-BP渣系活度预测模型有较好的预测精度。在此基础上建立了奥氏体不锈钢、铁素体不锈钢冶炼过程中钢液脱氧热力学模型。热力学模型表明,钢液中铬质量分数越高,脱氧越困难;奥氏体不锈钢铝脱氧条件下,镍质量分数越高,脱氧能力越差;任何情况下降低熔渣中脱氧产物的活度都有利于降低平衡条件下钢液中溶解氧质量分数。     

Prediction of deoxidation and inclusion precipitation in semikilled steel

A generalized thermodynamic calculation procedure for the prediction of oxide inclusion precipitation of desired compositions for Mn-Si-Al deoxidation has been developed. The procedure directly uses established ternary iso-activity diagrams in the MnO-SiO₂-Al₂O₃ system, and does not assume any slag model. The thermodynamic data required for calculation, such as deoxidation constants, interaction coefficients, and activity vs composition relations in the oxide phase, reported in the literature, were examined and the ones considered to be most satisfactory were accepted. On the basis of the computed results for inclusions in the spessartite phase field of the MnO-SiO₂-Al₂O₃ system, discussions have been presented on the applicability of the regular solution model as well as an empirical model reported in the literature. Some predictions for plain carbon steels have also been included.     

Mullite as an electrochemical probe for the determination of low oxygen activity in liquid iron

Oxygen activities in liquid iron deoxidized with aluminium were measured at 1873 K, using a mullite electrolyte having a Cr-Cr₂O₃ reference mixture. These results were compared with those obtained using commercial tube-type ZrO₂-8 mol% MgO and plug-type ZrO₂-9 mol% MgO probes, along with oxygen activities calculated from analysis. Oxygen activities from EMF measurements using mullite and plug-type probes were found to be in agreement with those calculated from the Al /AI₂O₃ equilibrium and those estimated from analyzed oxygen contents. Polarization effect due to electrochemical oxygen transport was observed in a commercial tube-type ZrO₂-based probe. Supersaturation in liquid iron deoxidized with aluminium was also measured at 1873 K.     

铝耗及终脱氧氧位对IF钢水口结瘤的影响

通过对IF钢水口结瘤物各层成分及形貌的分析,得出造成水口结瘤的主要原因是Al₂O₃夹杂物在水口内壁不断聚集和烧结.比较了不同铝耗对塞棒杆位的影响,铝耗较高时,塞棒杆位明显上涨,当铝耗超过3.5 kg·t-1时,可能导致钢水断浇等生产事故.对平均铝耗及平均终脱氧氧位作了定义,随着平均铝耗的增加,单支下水口浇铸时间呈下降趋势,当平均铝耗超过3.5 kg·t^-1时,单支下水口浇铸时间低于50 min.铝耗随终脱氧氧位提高呈增加趋势,当终脱氧氧位在600×10^-6以上时,铝耗可能超过3.0 kg·t^-1;而平均终脱氧氧位超过600×10^-6时,单支下水口浇铸时间可能低于50 min.     

钢水洁静度的研究及控制

通过对20MnSi钢进行钢中气体、杂质、金相等分析,对水钢连铸小方坯中的钢水洁静度进行研究,就 钢中夹杂物的生成和存在形式,夹杂物的数量、尺寸、形态、分布等进行测试与分析,就控制钢中夹杂物可能采 取的手段作一综述。