Galvalume镀层金属间化合物层的生长及缺陷研究

通过分析热浸镀Galvalume镀层金属间化合物层的生长和缺陷,发现短时间的热浸镀,钢基表面能形成完整的金属间化合物层,形成的金属间化合物层均由铁铝化合物相（Fe2A15、FeAl3）和T5相两层组成。随着浸镀时间的延长,清晰可见Fe2A15、FeAl,和T5三个相层。在长时间的热浸镀过程中,钢基不断被铝锌液侵蚀。在生产过程中,镀层金属间化合物层存在大量的缺陷,将加剧铝锌液对钢基的侵蚀,甚至导致钢基剥落。     

锌锅温度场的研究及应对措施

1前言板带是钢铁工业的主要产品之一,而汽车镀锌板是板带产品要求最为严格的钢板,其表面形貌对于后续冲压涂漆等有很大的影响,由于镀锌裸板需要在液态锌中浸镀,表面上粘附的锌渣是影响镀锌板表观质量的重要因素,锌渣由Al+Fe反应生成,锌渣包括浮渣和底渣,浮渣和底渣的产生不但使得锌的利用率下降,而且附着在镀层表面影响产品质量,且一旦生成反应不可逆,既锌渣不会重新溶解。锌锅中,锌液温度分布将直接影响铁-锌之间的,反应速度和铁损,因而对锌渣的产生造成较大的影响,本文仅从锌液温度方面对锌渣形成进行分析,找到温度对锌渣形成的因素原因及控制措施。     

Fe--Sialon复合材料中 Fe3 Si 合成热力学分析及实验验证

对淤泥沙原料中Fe3O4及其中间产物Fe O和Fe可能参与的反应进行了热力学分析.结合绘制的不同CO分压下Fe-Si体系在C和Si O2过量下的优势区相图及Fe-O-N体系热力学参数状态图,得出体系中Fe元素最终以Fe3Si形式存在,为淤泥沙合成O'-Sialon-Si C-Fe3Si(即Fe-Sialon)复合材料提供了热力学理论依据.在热力学分析的基础上,以淤泥沙为主要原料,采用碳热还原氮化法制备了Fe-Sialon复合材料,并借助X射线衍射仪和扫描电子显微镜对烧结体的物相和显微形貌进行了表征,得出产物的主晶相为O'-Sialon,还含有少量的Si C和Fe3Si相,晶粒呈现为纤维状、絮状或短柱状,与热力学分析结果(Fe元素最终以Fe3Si存在)吻合.     

CaO-SiO2-FeOx-MgO氧化物体系液相区及相关系计算

焚烧垃圾底灰的主要氧化物组分为SiO2、CaO、Al2O3、Fe2O3、Na2O和MgO,该六元体系相关系和热力学性质对于焚烧底灰渣化处理中玻璃相形成以及重金属低浸出具有重要影响.本文运用计算热力学理论及相图计算方法,对CaO-SiO2-FeOx-MgO四元氧化物体系的热力学性质进行了研究,获得了描述该四元系液相吉布斯自由能的模型参数,并依此计算了不同温度及氧分压下SiO2-FeOx-MgO、CaO-SiO2-FeOx和CaO-SiO2-FeOx-MgO体系液相区和高铁区域的相关系.计算结果表明温度及氧分压对上述3个氧化物体系的液相区及高FeOx区域的相平衡关系具有较大影响     

从钼氨浸渣中提取钼的研究

采用XRD对钼氨浸渣的物相进行了分析,结果表明钼氨浸渣中存在钼酸钙及少量低价钼。碳酸钠浸出钼酸钙的热力学研究表明,当温度高于86℃时,浸出反应能自发进行,且温度越高,浸出反应越容易进行。在高温条件下采用碳酸钠浸出钼氨浸渣的优化工艺参数为:碳酸钠浓度70g/L、温度190℃、时间1.5h、液固比7∶1。在此条件下,钼浸出率达91.44%,残渣钼含量降至1.91%,且钼氨浸渣中的钼酸钙全部被浸出。浸出过程动力学研究结果表明,在高温条件下碳酸钠浸出钼氨浸渣反应的表观活化能为10.38kJ/mol,浸出过程受固膜扩散控制。     

钛渣电铝热还原一步合成Ti-Al-xFe-ySi多元合金热力学分析

从理论上分析了钛渣铝热还原制备Ti-Al-xFe-ySi多元合金的可行性,计算并分析了钛渣中金属氧化物与铝还原过程中可能的化学反应,讨论了钛渣中氧化物还原反应顺序的优先程度。结果表明,钛渣铝热还原制备钛铝基多元合金是可行的。从热力学分析了制备的合金中可能出现的二元合金相,主要为Ti5Si3、TiAl3和TiFe,其中Ti5Si3最易生成,研究结果较好地满足了热力学分析结果,制备的合金主要物相为Al2.68Mn0.32Ti和Al3Ti0.75Fe0.25,还有少量的TiFe和Ti3SiC2相。     

M42高速钢电渣重熔及锻造退火后碳化物的析出

 通过X射线衍射分析、光学显微镜和透射式电子显微镜观察以及相关热力学计算,对比研究了M42高速钢电渣锭及锻后退火两种状态所析出碳化物的类型、尺寸、分布及析出条件。得出M42高速钢电渣锭中的碳化物主要为Mo2C亚稳态碳化物和少量Cr7C3碳化物,Mo2C碳化物尺寸较大,主要呈层片状、纤维状和棒状沿晶界析出。锻造退火后的M42高速钢中碳化物类型主要为Cr7C3,VC和Fe2Mo4C,平均尺寸小于10 μm且分布均匀,形态以方形、不规则球形和小颗粒为主。M42高速钢电渣锭中的Mo2C在锻造过程中可以分解为Fe2Mo4C和VC。根据冶金热力学计算得出,Mo2C和VC在固液两相区析出,析出温度分别为1 229 和1 222 ℃;Cr7C3在固相中析出,析出温度为842 ℃。     

CaO-SiO2-FeOx及CaO-SiO2-P2O5-FeOx渣系热力学性质的研究

CaO-SiO2-FeOx三元渣系和CaO-SiO2-P2O5-FeOx四元渣系是转炉脱磷用渣的主要子渣系,研究这两种渣系的热力学性质可为脱磷渣的高效利用提供理论依据。利于相图软件FactSage分别绘制了这两种渣系的相图,并分析了温度和氧分压对体系相平衡关系和液相线的影响规律。分析结果表明:升高温度会使这两种渣系的液相区扩大,初晶相稳定区域显著减小;降低氧分压会导致尖晶石固溶体相的初晶区消失,磷石英(SiO2)、伪硅灰石(CaSiO3)、α’-Ca2SiO4固溶体相减小。     

热浸镀5%Al-Zn合金钢板金属间化合物的形成及其对涂层显微结构的影响

该项研究系由我国台湾省台南市的一大学的材料工程系完成。研究了热浸镀5％Al一Zn钢板时，镇液温度（在金属间化合物形成区间的温度）的变化，对涂层显微组织的影响情况。研究表明，当浸镀液温度高于18OC，钢板浸镀lmin时，所得的镀层外表面粗糙。将镀液温度降至‘16OC，但延长浸镀时间至5n。in以上时，镀层外表面亦很粗糙。电子显微镜检测结果表明，粗糙的外表是由于涂层中相应生成了铁～锡金属间化合物。c18oC以上温度浸镇时，涂层晶粒长大快，这与此时金属间化合物快速形成密切相关，金属间化合物层的厚度可达整个涂层厚的7O％。热浸…     

MgO对镍转炉溅渣护炉炉渣性能的影响

炼镍转炉溅渣护炉过程渣中MgO含量明显增加,为了研究溅渣体系合理渣型和提高溅渣效果,利用热力学计算和热态试验结合的方法分析了MgO对不同Fe2O3含量炉渣的液相比例、低熔点区比例、熔化温度和粘度等的影响。结果表明:ω(Fe2O3)=3.45%～13.69%时,随着MgO含量增加,炉渣高熔点铁镁橄榄石相比例增加,液相比例(CT)和低熔点区(P<1250)比例下降,熔化温度和粘度上升;ω(Fe2O3)>13.69%时,磁铁矿比例大大增加,熔化温度大幅上升,炉渣粘度略有下降。5.0%的MgO使C1200较大,C1250较小,熔化温度达1369℃,炉渣的粘结性和抗熔损性良好,5%MgO-FeO-Fe2O3-SiO2为溅渣合理渣型。     

Fe-Al系金属间化合物多孔材料的制备及孔结构表征

以Fe、Al元素粉末为原料,采用分段无压反应合成工艺制备Fe-Al系金属间化合物多孔材料,并对其孔结构进行表征.通过改变Fe-Al元素的配比,研究Al含量对Fe-Al金属间化合物多孔材料透气度和最大孔径以及孔隙度的影响.结果表明,Al含量对Fe-Al金属间化合物多孔材料孔隙度的影响显著.在Al含量(质量分数)20%～45%的范围内,Fe-Al金属间化合物多孔材料的孔隙度与Al含量之间遵循严格的直线增加规律;Al含量对Fe-Al金属间化合物多孔材料最大孔径和透气度的影响与对孔隙度的影响相似.本实验条件下Fe-Al系金属间化合物多孔材料中透气度(k),开孔隙度(θ)和最大孔径(dm)之间的定量关系式为:K=0.2538dm2θ.     

Thermodynamic modeling of the interaction of high-level element and oxygen in iron-based melt

The main reactions of calcium, cerium, lanthanum, silicon, and complex alloys with the active additive Ca–Si, Ca–Al, Ce–Si, La–Si, Ce–La, or Ce–Ca–Al are subjected to thermal analysis. On the basis of binary and ternary fusibility diagrams, the thermodynamic data are refined for the main reactions between complex alloys with rare-earth elements and the oxygen present in the liquid metal. Solubility surfaces are plotted for components of the Fe–Si–Ce–O, Fe–Si–La–O, Fe–Ce–La–O, and Fe–Ca–Al–Ce–O systems. From those diagrams, optimal compositions of complex alloys with rare-earth elements in terms of nonmetallic-inclusion formation are established by plotting the consumption of the active components. For each group of steels, the quantitative elementary composition of the active components used for reduction and modification of the nonmetallic inclusions must be calculated. The chemical and phase composition of the nonmetallic inclusions may be very complex even in the final stages of the reduction of oxides. A method is developed for taking account of the polyvalency of cerium in reduction processes. The thermodynamic data and diagrams obtained help provide a better understanding of the complex heterogeneous processes within multicomponent systems that contain liquid metals. In combination with experimental data for the solubility surfaces of the components and the consumption diagrams, it is possible to track the transitions from the nonequilibrium state of the metallurgical system to the equilibrium state. In other words, the degree of refining of the metal and the equilibrium composition of the nonmetallic inclusions may be determined.     

Simulation of flow in a continuous galvanizing bath: Part II. Transient aluminum distribution resulting from ingot addition

The coupled phenomena of momentum, heat, and mass transfer were simulated in order to predict and to better understand the generation and movement of intermetallic dross particles within certain regions of a typical galvanizing bath. Solutions for the temperature and aluminum concentration can be correlated with the solubility limits of aluminum (Al) and iron (Fe) to determine the amount of precipitated aluminum in the form of Fe₂Al₅ top dross. Software developed by the Industrial Materials Institute of the National Research Council of Canada (IMI-NRC), including k-ε turbulence modeling for heat and mass transfer, was adapted for the simulation of a sequence of operating parameters. Each case was modeled over a period of 1 hour, taking into account an ingot-melting period followed by a nonmelting period. The presence of an ingot significantly changes the temperature distribution and also results in important variations in the local aluminum concentration, since the makeup ingot has a higher aluminum concentration. The simulation showed that during the ingot melting, the total aluminum concentration is higher at the ingot side of the bath than at the strip exit side. The region below the ingot presents the highest aluminum concentration, whereas lower aluminum concentrations were found in the region above the sink roll, between the strip and the free surface. It was shown that precipitates form near the ingot surface because this region is surrounded by a solution at 420 °C, which is lower than the average bath temperature of 460 °C. When no ingot is present, the total aluminum concentration becomes much more uniform and decreases with time at a constant rate, depending on the coating thickness. This information is of major significance in the prediction of the formation of dross particles, which can cause defects on the coated product.     

等离子喷涂制备铁基复合陶瓷涂层的研究

以铝粉和氧化铁粉作原料,采用等离子反应合成技术制备出了金属颗粒增韧的FeAl2O4-Al2O3-Fe复合陶瓷涂层。研究分析了复合涂层的组织及其性能。结果表明：等离子反应合成得到了以层状基体相FeAl2O4与硬质相Al2O3为骨架,球状Fe相弥散分布于基体相上的复合涂层。复合涂层的断裂韧性和结合强度明显优于普通Al2O3涂层,特别是复合涂层的具有较高的耐磨性能。     

宝钢1550CGL锌锅运行状态的测试与分析

对宝钢1550mm冷轧厂热镀锌机组(CGL)生产的热镀锌(GI)及合金化热镀锌(GA)钢板,测定了两种产品稳定期间锌锅中锌、铁、铝的输入和输出的物质平衡状态下,在锌锅中各个垂直和水平方向上的温度和成分分布,并用金相和物理测试手段对锌渣的种类、分布和大小进行了分析,从而直观地描述了宝钢1550mm冷轧厂锌锅正常生产时的运行状态,有利于理解锌锅的冶金行为并优化控制锌锅的物质平衡.     

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.     

Reaction of FeO-V2O5 System at High Temperature

 FeO and V2O5 are two main components of the obtained vanadium steel slag, and the reaction of FeO-V2O5 system determines the physical property of the slag. Through thermodynamic calculation and experimental study, it can be found that within the ranges of steel-making temperature, V2O5 is reduced to VO2. As FeO exists in FeO-V2O5 system, VO2 will be reduced to V2O3 further while FeO is oxidized to Fe2O3. In this multi-system, as the content of FeO and temperature increase, the system will have products in turn such as V3O5, V3O4, FeVO4, Fe2VO4 and Fe3O4. The products are mainly V3O5 and Fe2O3 when the content of FeO is 0.58 mol and the temperature is 1100 K, and as the temperature increases, Fe2O3 starts to react with V2O5 and then generates FeVO4; FeVO4 disappears while the content of FeO and the temperature increase at the same time, and then Fe2VO4 is generated by the reaction of FeO, Fe2O3 and V2O3. Iron oxides are also generated such as Fe3O4 and so on.     

低温烧结制备超细晶FeAl合金及性能的研究

Fe、Al混合粉末经高能球磨后,在560～620℃进行低温烧结。结果表明,低温烧结温度对合金组织有明显的影响,经过12h球磨,在620℃烧结4h,可以得到超细晶FeAl金属间化合物。SEM、AFM和XRD的分析结果表明,晶粒均匀,呈等轴状,大小约为30nm左右。超细晶FeAl金属间化合物的显微硬度较低,断裂为韧窝断口,呈现塑性变形特征。