80 t单嘴真空精炼炉冶金功能的生产实验分析

对80t单嘴真空精炼炉的冶金功能进行了生产实验分析,结果表明,单嘴精炼炉具有脱氢、脱氮、脱碳、脱氧、脱硫、化学升温、去除钢中夹杂物和合金成分调整等冶金功能。利用80t单嘴精炼炉精炼钢水,实验合结钢中氢含量可达(0.9～1.2) ×10^-6、氧含量(9～12) ×10^-6,超低碳钢中碳含量为(10～20) ×10^-6、氮含量(29～37) ×10^-6、钢水中硫含量为(10～30) ×10^-6;单嘴精炼炉具有较好的化学升温效果、去除夹杂物效果同RH精炼炉相当;采用单嘴精炼炉进行20炉超低碳钢合金成分调整结果表明,合金收得率高,硅、锰、铝的收得率分别为93%～96%、93%～95%、64%～67%。     

单嘴浸渍管RH和弓形浸渍管RH的应用效果

敬业钢铁有限公司现场试验了单嘴浸渍管结构RH炉和弓形浸渍管结构RH炉真空精炼超低碳钢的应用效果,记录两种RH炉提升气体流量和真空度的变化,多次取样检测钢液中w([C])和w([Mn]),分析对比两种RH炉的脱碳效果和混匀时间。结果显示,在真空处理6 min内,两种RH炉的真空度都可降至100 Pa以下,10 min后稳定在50 Pa左右;在真空处理20 min内,前者钢中w([C])基本脱至0.001 0%~0.001 5%,而后者钢中w([C])可以脱至0.000 5%左右,后者的脱碳速率也明显快于前者;前者和后者的混匀时间分别在3和1 min左右。结果表明,后者的冶炼效果明显优于前者,弓形浸渍管比单嘴浸渍管更适用于小吨位RH真空精炼炉。     

80t单嘴真空精炼装置脱碳工艺试验研究

单嘴真空精炼装置是一种新型的炉外精炼设备。采用80t单嘴真空精炼装置进行了127炉脱碳工业试验,试验结果表明,单嘴真空精炼装置可以获得较好的脱碳效果,试验最低碳质量分数为10×10^-6。主要介绍了单嘴精炼装置的试验情况,分析了钢包底吹气体流量、钢包内渣层厚度、钢包自由空间高度、脱碳时间、钢水温度及成分对脱碳效果的影响...     

80t多功能单嘴真空精炼炉脱硫冶金特性

为了开发多功能单嘴真空精炼炉的脱硫工艺,在80tRH基础上改造的80t多功能单嘴真空精炼炉进行了37炉次的冶炼超低碳超低硫钢种的脱硫试验。试验结果表明：多功能单嘴真空精炼炉具有较好的脱硫效果,最高脱硫率可达到81．2％,钢液中最低w（S）可降低至10×10^-6。研究了脱硫操作过程中脱硫剂、脱氧剂加入量及钢包渣厚对80...     

单嘴精炼炉真空处理过程气泡行为及冶金效果研究

根据相似理论,以钢厂80 t单嘴精炼炉1:4的水模型模拟了单嘴精炼炉内气泡行为,分析了吹气流量(2～10 L/min)、吹气塞直径(15～30 mm)对气泡行为、混匀时间的影响。水模拟结果表明,随吹气流量增加,混匀时间减少,但吹气流量≥6 L/min,混匀时间没有显著变化;在相同吹气量下,吹气塞直径增加,混匀时间减少。实验研究基础上,在80 t单嘴精炼炉上进行了超低碳钢的生产试验,结果表明单嘴精炼炉在18 min脱碳时间内,钢中碳含量可降到10×10^-6;脱硫剂消耗4 kg/t的情况下,成品钢中S含量为(20～30)×10^-6,脱硫率平均达49%;吹氩强度平均为4 L/(t·min),是相同吨位RH的25%。     

炉外精炼新技术(二)钢铁冶炼新技术讲座之十

二、炉外精炼设备的选型及配置条件1选型原则1.1以钢种为中心,正确选择精炼设备CAS-OB是最简单的非真空精炼设备,多适用于普碳钢、低合金钢等以化学成分交货的钢种。LF有很强的清洗精炼和加热功能,适宜冶炼低氧钢、低硫钢和高合金钢。VD脱碳能力弱(受钢包净高度的限制),具备一定的钢渣精炼功能,适宜生产重轨、轴承、齿轮等气体含量和夹杂物要求严格的优质钢种。RH脱碳能力强,适宜大量生产超低碳钢、IF钢(低N无间隙钢)。VOD、AOD等门用于生产不锈钢。此外,经常采用不同功能的精炼炉组合使用,如CAS-RH LF-RH LF-VD AOD-VOD。1…     

LF炉外精炼自动化冶炼研究与应用

针对唐钢一钢轧厂150 t LF炉外精炼自动化冶炼可行性展开研究,对LF炉外精炼炉冶炼过程中温度、成分、钢渣等变化参数进行统计分析,优化二级冶炼模型,结合LF炉外精炼炉实际冶炼过程步骤,制定出完整的LF炉外精炼自动化冶炼程序并在实际生产中进行了应用,实现LF炉外精炼温度、成分自动化冶炼。     

单嘴精炼炉真空处理过程钢液流动行为模拟研究

根据相似理论,以国内某厂80t单嘴精炼炉1:4的水模型模拟了单嘴精炼炉吹气流量、吹气位置等工艺参数对混匀时间的影响.在水模型研究的基础上,通过数学模型仿真计算分析了不同吹气流量、吹气位置对单嘴精炼炉内流场的影响,数值计算结果与试验结果吻合较好.研究结果表明:吹气流量为6L/min、吹气位置γ/R为0.5范围内有利于缩短...     

莱钢130t RH冶炼超低碳钢工艺实践

根据RH真空脱碳机理,分析了提升气体流量、RH精炼炉进站碳氧质量分数、炉渣改质、吹氧制度对RH精炼炉真空脱碳速率的影响,确定了超低碳钢的冶炼操作工艺。     

RH精炼过程计算机控制系统的发展

随着ＲＨ真空精炼设备和工艺技术的不断进步,ＲＨ真空精炼设备已在众多炉外精炼中起到不可替代的重要作用,适用于大量生产优质超低碳钢。实践证明,在ＲＨ处理过程中,采用计算机自动控制系统,对稳定提高钢质量,高效、低耗生产具有重要意义。对此,结合上ＲＨ真空精炼过程计算机自动控制系统的发展,对ＲＨ过程计算机控制系统的构成、特点和控制模型的功能等进行了综合评述。通过开发武钢１ＲＨＫＴＢ精炼过程控制模型的实践,提     

Mathematical Simulation of Flow Field for Molten Steel in an 80–ton Single Snorkel Vacuum Refining Furnace

The three–dimensional flow field of molten steel in an 80–ton single snorkel vacuum refining furnace has been mathematically simulated to attain the optimal configuration and operation parameters, such as the bottom blowing Ar flow rate, the eccentric position of bottom blowing Ar port at ladle bottom, the single snorkel inner diameter, and the single snorkel immersion depth into molten steel. The mathematical simulation results show that a stable flow field of molten steel can be achieved in 70–second; meanwhile, the maximal circulation intensity of molten steel in the 80–ton single snorkel vacuum refining furnace can be found on a cross–section with y as 0 mm based on the middle of ladle bottom as circular point of the Cartesian space coordinate under the condition of injecting Ar gas on x coordinate considering the asymmetry of flow field for molten steel in the single snorkel vacuum refining furnace. The recommended parameters of the 80–ton single snorkel vacuum refining furnace with ideal circulation intensity as 970.1 kg/s are the bottom blowing Ar flow rate as 450–500 Nl/min, the eccentric position of bottom blowing Ar port as 250 mm, the single snorkel inner diameter as 1000 mm, and the single snorkel immersion depth as 500 mm.     

Mathematical Modelling of Molten Steel Flow Process in a Whole RH Degasser during the Vacuum Circulation Refining Process: Application of the Model and Results

A three‐dimensional mathematical model for the molten steel flow during the RH refining process has been applied to the circulatory flow processes in both a practical RH degasser and its water model unit. The model was presented earlier [1] and one of its characteristics is that ladle, snorkels and vacuum vessel are regarded as a whole. Using this model, the fluid flow field and the gas holdups of liquid phases and others have been computed respectively for a 90 t RH degasser and its water model unit with a 1/5 linear scale. The results show that the mathematical model can properly describe the flow pattern of molten steel during the refining process in an RH degasser. Except in the area close to the liquid's free surface and in the zone between the two snorkels in the ladle, a strong mixing of the molten steel occurs, especially in the vacuum vessel. However, there is a boundary layer between the descending liquid stream from the down‐snorkel and its surrounding liquid, which is a typical liquid‐liquid two‐phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is ascending mostly near the up‐snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and molten steel in the up‐snorkel is closer to an annular flow. The calculated circulation rates for the water model unit at different lifting gas rates are in good agreement with experimentally determined values.     

氩氧精炼工艺是铁合金精炼技术的发展方向

由于精品钢及机械制造业高性能构件生产的需求,对低杂质精炼铁合金的需求逐年增加。为缩短工艺流程,降低能耗,减少渣量及硅铬合金中间产品及含有六价铬废弃物的产生,通过以氧代电,开发出一种新型精炼铁合金生产工艺和装备,生产低杂质的精品合金,降低冶炼综合能耗,减少精炼工艺的排渣量,杜绝生产环节中产生危险废弃物,实现工艺过程渣、尘循环利用,提高了产品质量,降低了生产成本,满足了精品钢及高性能构件生产的需求。     

Study on Control Technology of Slag Composition for Low-Sulfur and Low-Oxygen Steel

In order to reduce the content of oxygen and sulfur in steel, and produce low-sulfur and low-oxygen steel, study on slag has been carried out. Refining slag system of CaO-SiO2-Al2O3 is put forward with the consideration of slag amount from converter, oxidizability of slag and activity of oxygen in molten steel. On this basis, refining slagging system for low-sulfur and low-oxygen steel has been developed combined with the modification of slag from converter and composition control of refining slag in LF treatment process. The results show that oxygen content is not more than 15×10-6, as well as sulfur content is as low as 0.005% in tube blank steel. And it achieves the production of low-sulfur and low-oxygen steel.     

超低碳钢LF-RH双联精炼工艺的开发

介绍了唐山国丰钢铁有限公司第一炼钢厂RH投产后超低碳钢的生产工艺开发情况。通过对不同的精炼工艺路线进行对比,使用优化的LF-RH精炼工艺,实现对钢水巾C、N等元素的稳定控制,满足多炉连浇的生产组织需要。     

Development of RH refining technology at Baosteel

With the strong demand for the development of automobile sheets, tin plates, household appliances, silicon steel, pipeline steel and other products as well as for the quality improvement of steel products, remarkable progress has been made in RH refining technology and equipment design since Baosteel began production more than 20 years ago. The vacuum degassing ratio of Baosteel has jumped from 35% in the initial stage when Baosteel began production, to the current ratio of approximately 60%, and will soon reach 75% in the near future. The independent innovations in RH refming technology in Baosteel, such as RH equipment optimization, vacuum decarburization, inclusion control, deoxidation, desulfurization, rhythm adjustment between primary steelmaking and continuous casting, the high efficiency of the RH refining process, and other aspects of RH technology, have all effectively met the requirements of developing new steel products, quality improvement and logistical control. Complete sets of RH equipment and refining technology have been successfully exported to the domestic steel plants. In the future, Baosteel will make further efforts to improve efficiency, stabilize production and quality, and realize special line production, so that the RH degasser will play a greater role in Baosteel.     

Mathematical modelling of molten steel flow in a whole degasser during RH refining process

Abstract

A three-dimensional mathematical model for molten steel flow in a whole degasser during the RH (Ruhrstahl–Heraeus) refining process is proposed. The model has been developed considering the physical characteristics of the process, particularly the behaviour of gas–liquid two phase flow in the up snorkel and the momentum exchange between the two phases. The fluid flow fields and gas holdups of liquid phases, among other parameters, in a 90 t RH degasser and a water model unit of one-fifth linear scale have been computed using this mathematical model. The results show that the flow pattern of molten steel in a whole RH degasser can be well represented by the mathematical model. Apart from the area close to the free surface and the zone between the two snorkels in the ladle, the molten steel in an RH degasser, especially in the vacuum vessel, is reasonably fully mixed during the refining process. However, there is a boundary layer between the descending liquid stream from the down snorkel and the surrounding liquid, which is typical liquid–liquid two phase flow, and the molten steel in the ladle is not perfectly mixed. The blown lifting gas ascends mostly near the up snorkel wall, which is more obvious under the conditions of an actual RH degasser, and the flow pattern of bubbles and molten steel in the up snorkel is closer to annular flow. Calculated circulation rates for the water model unit at various lifting gas rates are in good agreement with values determined by means of water modelling experiments.