连铸结晶器保护渣自动给料机的开发与应用

连铸机浇铸时结晶器加保护渣的自动化是连铸自动化生产中不可缺少的一项.本文综合评述了国内首台自行研制并应用于实践的连铸结晶器保护渣自动给料机的结构原理、应用情况及其经济效益.     

自动加渣机运动机制研究

本文通过对加渣管摆动与小车线性运动关系的分析，获得减小渣管摆动与小车行走配合误差的最佳方法。利用这一方法设计自动加渣机，可以提高自动加渣机本身结构的紧凑性，使其在有限的空间内能够正常工作，保证加渣机始终处于稳定的工作状态，确保了结晶器中的保护渣流量恒定，提高了连铸坯的表面质量。     

自动加渣机器人在八钢板坯连铸的应用实践

文章介绍了八钢二炼钢板坯连铸引入了结晶器保护渣机器人加渣系统,阐述了自动加渣系统工作原理及设备设施。投入自动加渣机器人后,加渣实现了"均匀覆盖,液渣层稳定"、漏钢预报报警次数降低、铸坯表面质量提高、改善现场作业环境、降低职工劳动强度等应用效果。针对自动加渣机器人投用后遇到的典型问题提出了解决方法,自动加渣机器人为进一步实现连铸无人化浇铸奠定了基础。     

连铸结晶器保护渣生产及应用技术的发展

本文介绍了连铸结晶器保护渣生产及应用技术的发展现状，其中包括：结晶器保护渣的最佳选择；结晶器保护渣的性能选择；结晶器保护渣的成分和类型选择；结晶器保护渣中炭的选择。同时概述了结晶器保护渣的应用情况，并提出几点建议。     

高速连铸用保护渣

概述了高速连铸的特点及其对结晶器保护渣的要求，给出了高速连铸用结晶器保护渣的理化性能及所应具有的成分；总结了高拉速结晶器用保护渣的研究现状。     

双喷头移动式加渣机设计

针对钢厂炼钢过程中需人工加渣、保护渣添加频繁且加渣不均匀的问题,研制了一种自动加渣机.自动加渣机主要包括PLC控制系统、料仓、软管、空气放大器、螺旋送料器和伺服直线导轨加料机构.双喷头的设计可实现加渣口全覆盖,并减少填料频率.经过运行试验,保护渣从料仓下落至螺旋送料器内,再通过螺旋推送和吹渣装置输送到结晶器中,实现均匀...     

宽厚板坯连铸自动加渣机的应用实践

介绍了鞍钢股份有限公司鲅鱼圈钢铁分公司宽厚板坯连铸机结晶器自动加渣系统的工作原理、设备组成、系统技术特点及控制功能。实践表明,自动加渣方式下的保护渣铺展及熔化状态、液渣层厚度及结晶器传热速度控制的稳定性均优于人工推渣方式,浇注各钢种的平均罐数漏钢报警率和铸坯表面纵裂及凹陷发生率均明显降低。     

结晶器保护渣性能和使用工艺

对结晶器保护渣的性能作了描述；对结晶器保护渣的性能与工艺条件、钢种的优化匹配进行了探讨。     

结晶器保护渣粘度的测量

在过去几十年里,连铸是铸钢过程中的主要生产工艺流程。在此工艺过程中,结晶器保护渣在结晶器和坯壳之间起到润滑作用,保证连铸过程顺利地进行,同时保证铸坯质量。结晶器保护渣粘度是确定最佳浇铸条件的关键参数。为了确定结晶器保护渣的粘度参数,早期进行了几个试验研究,工业用渣以及合成渣的成分接近于工业用结晶器保护渣。然而,随着新钢种的不断更新,需要更多的洁净钢生产工艺操作,在生产中使用的结晶器保护渣,一般观察到Al2O3含量大约为2％-4％,由于这个原因,本文对瑞典钢厂使用的结晶器保护渣粘度开始进行试验性地研究,并且同时研究了氧化铝的溶解对其产生的影响,讨论了本研究中测量结晶器保护渣粘度的工业涵义。通过旋转圆筒式方法测量了连铸生产工艺中使用的结晶器保护渣粘度。本研究采用了7种工业用结晶器保护渣,对应的7种不同化学成分,也研究了结晶器保护渣中Al2O3含量的影响。甚至加入相对较小数量的Al2O3,也会对保护渣粘度产生较大的影响,测量温度范围从1373K到1673K。     

薄板坯高速连铸用结晶器保护渣

１前言欧州板坯连铸机自采用中间包至结晶器浸入式浇注技术迄今已３０多年了。起初，采用灰状结晶器保护渣和合成粉状保护渣；１９７６年，通过吹干法而开发了粒状结晶器保护渣。由于粒状保护渣均匀、流动性好、没有粉尘，所以有助于提高产品质量，改善铸机操作和环境条件...     

连铸结晶器振动技术的发展及应用

连铸结晶器振动装置的发展是随着人们对连铸工艺技术认识的不断深入而不断发展的过程.由于对振动曲线提出的不同要求,从而应运出不同形式的振动装置.重点介绍了京唐公司连铸液压振动的特点及应用.     

新临钢2#方坯连铸机结晶器的改造

结晶器能否正常使用,关系到铸机的产量,通过介绍结晶器结构的改造,对两种结构不同的结晶器在冷却效果、寿命、加工制作和经济效益进行了对比分析.     

国内模具钢的市场前景及生产现状

本文简要介绍了我国模具工业及模具钢的市场概况，分析了我国近几年的模具钢的生产现状及市场前景，探讨了发展我国模具钢的发展思路及策略。     

Challenge to control mould heat transfer during thin slab casting

Abstract

At the thin slab caster of Tata Steel, IJmuiden, mild cooling mould powders were introduced with the aim to control the mould heat transfer during casting. These mild cooling mould powders are characterised by specific values of basicity, solidification point and chemical composition. Application of these mould powders resulted in a redistribution of mould heat transfer during casting, i.e. a reduced and more stable mould heat transfer in the critical upper part of the mould and an increased mould heat transfer in the lower part of the mould. The average mould heat transfer and hence the shell thickness at mould exit are comparable to the standard powder. The application of mild cooling mould powders also resulted in improved solidification behaviour of the steel shell. A thinner chill zone with smaller thickness variations was observed. Furthermore, it was found that the mould taper required optimisation to match the changes in shrinkage behaviour to ensure uniform solidification. The use of mild cooling powders was observed to give an increase in mould friction. Mould thermal monitoring indicated that the solid slag films fractured (sheeting) in the upper part of the mould. However, no operational problems were reported, which indicate that the first 200 mm under the steel meniscus is essential for initial solidification and for the formation of a homogeneous steel shell. All these findings can be understood by considering the crystallisation properties of the mould slag, which include the cooling rate. Mild cooling has been shown to provide uniform heat transfer and adequate lubrication for high speed thin slab casting.     

F-free mould powders for low carbon steel slab casting – technological parameters and industrial trials

The choice of the mould powder for slab casting is a difficult task because mould powders have many important functions during the continuous casting of steel. CaF₂ is a key ingredient in conventional mould slags since it reduces the viscosity, the liquidus temperature and the break temperature. Fluorine in mould powders is undesirable from the environmental and health points of view due to the following reasons: (i) evolves easily from slags, producing health-injurious gaseous substances, such as hydrofluoric acid; (ii) creates problems for storage and utilisation of solid waste and (iii) causes machinery corrosion. Aim of the present work is to describe the development of a new F-free mould powder for low carbon steel slab casting replacing CaF₂ with B₂O₃. Laboratory tests and industrial trials were performed considering the technological parameters viscosity, break temperature and crystallisation tendency. From laboratory tests it was concluded that important technological parameters are similar when comparing the F-bearing mould powder (reference) and the new F-free B-bearing mould powder for low carbon steel slab casting: viscosity at 1300°C, break temperature, and crystallisation tendency. It was observed during industrial trials that a significant decrease of the submerged entry nozzle erosion was observed. The results were similar when comparing the F-bearing and the F-free performance: slag pool thickness measurements, melting behaviour, Al₂O₃ absorption, mould powder consumption and slabs superficial quality.     

Liquid steel flow in continuous casting machine: modelling and measurement

Abstract

Single phase (liquid steel) and two-phase (liquid steel and argon bubbles) three-dimensional computational fluid dynamic and heat transfer models were developed for the continuous casting machines of ArcelorMittal. The computational domains include tundishes, slide gates, submerged entry nozzles and moulds. The effects of buoyancy, tundish design, tundish practices, nozzle design and caster practices on flow structure were investigated. Mathematical modelling is discussed in detail. In addition, submeniscus velocity measurements in the slab caster mould are performed with the method of torque measurement. A consumable probe is inserted into the liquid steel meniscus from the top of the mould through mould powder and slag layer. The liquid steel flow applies a drag force to the probe, which then generates a torque. This torque value is measured and then converted back to velocity. The concept and challenges of the technique are discussed, and the effects of casting parameters on mould flow structure are investigated. Product quality in relation to real time meniscus velocity measurements is also discussed.     

板坯连铸机结晶器国产化改造

为了提高邯钢三炼钢板坯的产量和质量,邯钢对板坯连铸机结晶器进行了国产化改造。改造的内容有结晶器铜板材质、厚度、镀层、水槽,水冷梁把合螺栓、喷淋水系统、倒锥度、角缝、水槽密封、过滤网的设计改造等。通过改造,达到了预期的目标,一次拉钢量达到了8.3万吨,结晶器经过简单调整后,铜板镀层一次拉钢量已达到12万吨,产品质量显著提高,满足了生产工艺使用要求。     

板坯结晶器密封方式可靠性的研究

对连铸结晶器水冷系统的各种密封方式进行分析比较 ,提出了密封件的可靠对接方式以及合理密封结构 ,十分有效地解决了结晶器的渗漏难题 ,为结晶器制造企业提供了设计改进、制造工艺方面的经验     

Understanding mould powders for high-speed casting

The development and application of mould powder for high-speed continuous casting of steel is described. For thin slab casting, the main requirements are proper powder melting, undisturbed slag infiltration, adequate strand lubrication and the control of mould heat transfer. For increased casting speeds i.e. up to 8?m/min, slag infiltration and in particular the control of mould heat transfer via crystallisation of the slag film becomes even more important. It was found that a low powder consumption and hence a thin slag film is no restriction for an undisturbed thin slab casting process. Given a stable casting process and machine condition, the mould powder properties are not as critical as widely assumed.