浸入式水口燃烧式烘烤预热温度场研究

浸入式水口在浇钢以前必须进行充分预热 ,利用燃烧的煤气烘烤水口是常用的预热烘烤方式。本工作运用有限元技术对浸入式水口燃烧式烘烤预热的瞬态传热过程进行了研究 ,得到了水口烘烤预热后的温度场分布和水口的升温曲线。研究结果表明 ,在燃烧式预热烘烤方式下 ,水口沿轴线方向的温度变化梯度较大 ,水口颈部预热后的温度较低 ,是导致水口颈部频繁断裂和较易出现竹节样裂纹的主要原因。欲提高水口颈部的预热温度 ,必须改进水口的预热烘烤方式     

利用气体喷射引流技术强化浸入式水口的预热效果

为了提高现有抽风式预热烘烤方式下浸入式水口的预热效果 ,利用气体喷射引流原理 ,在靠近烘烤箱的抽风机吸气管道上增设一压缩空气管 ,构成简单喷射器 ,通过压缩空气的喷射引流来增加抽风流量 ,强化升温效果。研究表明 ,采用压缩空气引流后 ,可使抽风式烘烤装置的抽风流量由原来的 0 .2m3·s- 1提高到 0 .36m3·s- 1,水口的预热升温曲线更趋合理。采用压缩空气引流强化抽风预热烘烤 90min时 ,水口颈部外壁的温度提高 1 4 .8% ,比现有结构提高约 1 0 0℃ ,效果十分明显     

薄板坯连铸浸入式水口结构数值模拟

使用有限元计算方法开展薄板坯连铸浸入式水口流场的研究 ,分别对水口不同浸入深度的流场分布、水口出口不同角度的流场分布进行计算。结果发现 :水口的浸入深度在 30 0mm时较为合理 ;水口的出口角度以R1 5、60°、45°为宜     

塞棒和浸入式水口在预热期间的性能

介绍了浇铸前对塞棒和浸入式水口进行预热试验以及获得的试验结果。这两种制品的预热是影响耐火制品使用寿命的主要因素，而且会将塞棒和浸入式水口的热震降至最低，从而提高耐火材料的寿命。     

MOGUL型浸入式水口

为防止钢水在浸入式水口中的再次氧化，研制开发了一种新型的被称之为MOGUL的内衬结构，并用水模型进行了模拟试验。通过流速分布、流型特性等分析，指出新型浸入式水口(SEN)能有效抑制水口和结晶器内发生的钢水偏流现象，改善了钢水质量。     

隔热结构浸入式水口的传热模拟

1.前言 为了确认具有隔热结构的浸入式水口(见图1)的隔热效果,采用有限元法对操作中的水口温度分布变化情况进行了分析,并在已实用化的隔热层中充填陶瓷纤维和空心球。但是,有关隔热特性多不明确。因此,在本研究中根据模型试验及其结果进行数值分析,并将两水口的隔热效果进行了比较。2.操作中的分析     

Improving the erosion resistance of the submerged entry nozzle by applying an external electric field

In order to improve the erosion resistance of the submerged entry nozzle (SEN) in a continuous casting process, an electric field was applied between the SEN and the carbonaceous mold flux. In view of the extensive application of carbonaceous mold flux in the high-quality steel production process, the erosion behavior under carbonaceous mold flux was explored under the application of different electric fields, in terms of amplitude. The extracted results show that the erosion process between the carbonaceous mold flux and the SEN can be changed obviously by applying an external electric field. In addition, the increase of the carbon content in mold flux will promote the manifestation of erosion resistance effects. Under the control of the negative electric field, the decarburization, dissolution, adhesion, and reaction between the SEN and mold flux will be either suppressed or eliminated. Accordingly, the SEN material remains intact without any erosion and damage after the experiment. The application of electric field is anticipated to solve the problem of serious erosion in the SEN on the continuous casting process.     

Applied electric field on the reaction between submerged entry nozzle and alloy in the steel

In this study, the reactivity between nozzle and submerged entry nozzle and alloy elements in the steel (Al and Ce) under different electric field conditions was investigated. The results show that the decarburization of the nozzle is an important factor affecting the clogging behavior and steel quality. The external electric field directly affects and changes the decarburization, clogging, and reaction behavior between the nozzle and alloy in the steel. If the chemical reaction force between alloys and the nozzle is greater than the applied electric field force in actuality, the clogging will also occur on the submerged entry nozzle. In the future, this new method of controlling and changing the interfacial electric fields can be used to solve the problem of decarburization and clogging of the submerged entry nozzle.     

Slag corrosion between the mold flux and the submerged entry nozzle controlled by an external electric field

The corrosion mechanisms that occurred between the slag-line and mold flux under the applied external electric field are studied. The results show that the slag-line can be effectively protected when the slag-line is connected to the negative electrode, and the graphite as an auxiliary electrode is connected at positive potential. Under the applied negative electric field, a thick protective adhesion layer is formed on the surface of the slag-line due to the electrochemical reactions. Additionally, the slag-line material is further reacted with surface of the formed protective layer and generates another interface reaction layer. Under the effect of double protective layers, the slag-line can be perfectly devoid of corrosion attack under the negative electric field. The performance of the slag-line and the production time of the whole continuous casting can be improved. The external electric field is expected to be a new technical approach to alleviate corrosion of the SEN.     

ZrO2-CaO-C-SiO2浸入式水口用后显微结构分析

以锆酸钙和石墨为主材料,添加熔融石英、硅灰石、锆英石制成新型ZrO2-CaO-C-SiO2质浸入式水口,将其在鞍钢某连铸机上正常浇铸铝镇静钢6炉后,取钢液面下的水口残样,借助EDAX、SEM等手段对其显微结构进行了分析。结果表明:新型ZrO2-CaO-C-SiO2质浸入式水口在浇铸高铝镇静钢时抗Al2O3附着性能好,从钢液反应层到试样内部依次为致密层、过渡层、原砖层,其中致密层的性质决定着浸入式水口的使用性能。     

尖晶石质浸入式水口内衬的研究

以77%的电熔尖晶石(粒度≤1mm和≤0.074mm)、20%的α-Al2O3(≤2μm)和3%的电熔镁砂(≤0.074mm)为原料,分别在1000℃、1200℃、1500℃保温3h的条件下,研究了SiO2微粉外加量(分别为0、0.5%、1.0%、1.5%)对尖晶石材料烧结性能的影响,并在1450℃的还原性气氛下进行了尖晶石内衬材料与铝碳本体材料的复合试验。研究结果表明:在不过多增加尖晶石材料高温液相量的情况下,SiO2微粉的外加量为1.0%较为适宜;在尖晶石试样中同时添加1%SiO2微粉和3%电熔镁砂细粉能很好地降低其烧结温度,而且其热膨胀率与铝碳材料的热膨胀率较为接近,而尖晶石材料与铝碳材料的复合试验结果也表明,内衬和本体材料结合完好,且无裂纹出现。     

Interface reaction between alloys and submerged entry nozzle controlled by an electric current pulse

To solve the limitations of clogging and erosion of the submerged entry nozzle (SEN) for the production of high-quality special steel, the chemical reactivity between different alloys and the SEN and the interface reaction between alloys and the SEN controlled by an electric current pulse (ECP) were examined in this study. Results revealed that the chemical reactivity between different alloys and the SEN is different. For example, the reactivity between rare-earth metal and the SEN was strong, while that between Al and the SEN was extremely weak. At the same time, some differences between the clogging and interface reaction by ECP control were observed. Typically, at the positive electrode of the SEN, when a stable and dense clogging layer is formed, the internal SEN was effectively protected. However, at the negative electrode of the SEN, the decarburization rate of the SEN was accelerated by ECP, probably leading to a vicious circle of accelerated clogging and erosion of the SEN. Therefore, in the future, issues of clogging, erosion, infiltration, and decarbonization between active alloys and the SEN in the casting process may be solved and regulated by using the positive electric field of ECP. Meanwhile, the gain effect of ECP also helped to promote the homogenization of molten steel.     

防堵塞浸入式水口的使用

叙述了防堵塞浸入式水口的使用情况,对用后残砖分析表明以CaZrO3-C材料制作的浸入式水口,在浇注08Al钢时,有较好的使用效果,可实现多炉连浇。防堵塞效果主要取决于钢液中析出的Al2O3与防堵塞料的反应产物和钢水温度。