结晶器保护渣对连铸坯增碳的影响

本文研究了超低碳钢水通过连铸结晶器,铸坯含碳量增加的现象。讨论了含碳保护渣对超低碳钢铸坯增碳的影响,降低保护渣中碳含量,有利于减少铸坯增碳。     

超低碳钢连铸结晶器保护渣的研究动向

本文叙述了连铸超低碳钢时,结晶器保护渣对铸坯渗碳、增碳的作用机理,提出了减少、避免铸坯渗碳、增碳的途径。     

宝钢超低碳钢保护渣的开发

介绍了宝钢超低碳钢用保护渣的开发情况,指出降低保护渣中游离碳含量可有效防止超低碳钢增碳。从保护渣的使用性能,连铸工艺参数和减少铸坯增碳的效果三方面评价了开发的超低碳钢用保护渣,该类保护渣对ω（C）小于20×10^-6以下的超低碳钢类产品的生产有重要的意义。     

连铸结晶器保护渣对超低碳钢增碳的影响

分析了连铸结晶器保护渣引起超低碳钢铸坯增碳的原因。强调指出，除了富集碳层外，含有碳的熔渣层也是引起铸坯增碳不可忽视的原因。并阐述了铸坯增碳的机理，提出了防止铸坯增碳的措施     

超低碳钢连铸保护渣的发展

分析了在连铸过程中超低碳钢铸坯表面渗碳和结晶器内钢液增碳的原因,总结了国内外在抑制超低碳钢增碳方面所做的研究工作,对于研究和开发超低碳钢连铸保护渣具有一定的指导意义。     

超低碳钢连铸结晶用保护渣的超细复合处理

利用机械化学原理对连铸结晶器用保护渣进行超细复合处理,在保护渣微颗粒表面上生成微量碳化硅熔点材料,可有效地延缓保护渣熔化速度,大幅度减少保护渣中外加碳含量,避免超低碳钢铸坯增碳。     

超低碳钢连铸结晶器用保护渣的超细复合处理

利用机械化学原理对连铸结晶器用保护渣进行超细复合处理,在保护渣微颗粒表面上生成微量碳化硅高熔点材料,可有效地延缓保护渣熔化速度,大幅度减少保护渣中外加碳含量,避免超低碳钢铸坯增碳.     

应用6σ法控制超低碳钢连铸过程增碳

应用6σ法对影响连铸过程的增碳因素进行分析,使用单因子方差分析法考察了钢包砖衬、开浇渣种类、中间包涂料批次、中包渣批次、保护渣种类等因素对超低碳钢增碳量的影响.结果表明,钢包砖衬、开浇渣种类、保护渣种类是影响超低碳钢增碳的主要因素.根据研究结果,在生产中采取了使用无碳砖衬钢包、无碳开浇渣、低碳结晶器保护渣等措施,铸坯增碳量显著降低,超低碳钢连铸工序增碳量小于3×10-6.     

结晶器保护渣对超低碳钢增碳的影响

论述了连续铸造超低碳钢结晶器保护渣的特性和铸坯增碳机理,提出了选择保护渣的原则,并介绍了防止铸坯增碳的方法和经验。对降低超低碳钢在连续铸造过程中的增碳量具有一定的意义。     

连铸结晶器保护渣对超低碳风增碳的增加

分析了连续结晶器保护渣引起民超低碳钢铸坯增的原因。强调指出，除了富集碳层餐，含有碳的熔渣层也是引起铸坯增碳不可忽视的原因，并阐述了铸坯增碳的机理提出了防止铸坯增碳的措施。     

攀钢连铸坯角横裂缺陷产生的原因与对策

对攀钢Q235G钢连铸坯出现的角横裂缺陷进行了调查分析，在此基础上确定了连铸保护渣是引起角横裂的主要原因。并对保护渣的配方进行了改进，通过试验，研制出了适合攀钢普碳包晶钢用的连铸保护渣，有效地控制了Q235G钢连铸坯角的横裂缺陷。     

Mould Powder Development for Continuous Casting of Steel

Mould powders significantly determine the stability of the continuous casting process of steel at all casting speeds. The main functions of mould powders are to provide strand lubrication and to control the mould heat transfer in the horizontal direction between the steel shell and the copper mould. The composition, properties and operational performance of mould powders were investigated in detail with a focus on high-speed thin slab casting and conventional slab casting. Various advanced characterisation methods were applied, completed with experiments at laboratory scale and full-scale plant trials. It was found that melting of mould powder at the meniscus and crystallisation of the slag film are key processes during continuous casting. Both powder melting and slag crystallisation are primarily based on the composition of the mould powder and the mould slag. Additionally, the operational parameters during continuous casting will affect these processes as well. Results of the work are used for a further and more fundamental understanding of the mould powder functions and to guide mould powder design for various steel grades.     

降低超低碳钢结晶器液位波动及降级坯实践

针对鞍钢股份有限公司鲅鱼圈钢铁分公司生产超低碳钢时出现的结晶器液位波动和铸坯降级原因进行了分析,通过采取钢水顶渣改质、拉速调整、优化保护浇铸氩气流量、合理选择更换浸入式水口的时机及增加中间包钢水装入量等措施后,结晶器液位波动由14.38%降低到了7.44%,O5板比例由45.68%提高到58.23%。     

Research of Mold Powder for Ultra-Low Carbon Steel

It is well known,the physical properties andchemical composition of mold powder are ofimportance to achieve optimum operatingperformance and satisfactory final product quality.Mold powder has to serve some majorfunctions suchas thermal insulation,reoxidation protection,inclusion absorption,lubrication,and uniform heattransfer. The carbon addition has been an essentialcomponent in mold powder. Free carbon controlsthe powder melting by providing an inert betweenthe solid particles and/ or flux p…     

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.     

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.     

Carbon Pickup in Continuous Casting Processes

The quality of the as‐cast strand is influenced by a recarburization reaction since mould powder contains carbon particles necessary for a controlled melting behaviour. Intensive testing reveals a carbon pickup in the surface of the as‐cast strand depending on content and type of the carbon in the mould powder. Using the combination of laboratory trials and numerical simulations the effect of carbon pickup from mould powder to the strand shell was investigated. Laboratory experiments show that the recarburization of the liquid steel through the mould powder can be explained by Marangoni convection. This can happen in the slag rim when the carbon is entrapped by the solidifying steel and starts to diffuse inwards the strand.     

唐钢超低碳IF钢生产实践及洁净度控制

介绍了唐钢铁水预处理→BOF→RH→薄板坯连铸连轧工艺冶炼超低碳IF钢的生产实践,重点讨论了钢中主要成分和钢水洁净度的控制措施及效果。