连铸结晶器保护渣的应用试验

进行了３种连铸结晶器保护渣的大生产对比应用及批量试验，结果表明，与原用ＬＪ－１保护渣比使用ＧＦ－２渣浇铸能降低铸机拉漏率，提高铸坯一级品率７％－１５％，增加对钢水中Ａｌ２Ｏ３夹杂的吸收，减轻浸入式石英水口的侵蚀，并且保护渣单耗明显降低，铸坯成材率有所提高。     

高拉速结晶器保护渣的工业试验

高拉速结晶器保护渣的工业性试验是在鞍钢第三炼钢厂大型板坯连铸机上进行的。试验结果表明,AGL—2保护渣基本上满足了连铸机浇铸普通碳素钢的要求;使用AGL—2保护渣所浇铸的板坯质量是良好的,表面清理率在0.2%以下,板坯质量合格率达99.5%以上;内部夹杂物含量与使用进口渣时基本相同。     

连铸结晶器保护渣的应用试验

本试验测试了三种连铸结晶器保护渣的主要理化性能，生产对比应用及批量试验结果表明：使用ＧＦ－２渣浇铸，与原用ＬＪ－１渣比较能降低铸机拉漏率；提高铸坯一级品率７％－１５％；增加对钢水中Ａｌ２Ｏ３夹杂的吸收，减轻浸入式石英水口的侵蚀；降低保护渣单耗，提高铸坯成材率。目前ＧＦ－２渣已在一炼钢厂推广应用，获得了显著的经济效益。     

结晶器保护渣对浸入式水口蚀损的影响

为了阐明浸入式水口在保护渣线周围使用的ＺｒＯ２－石墨质耐火材料的蚀损机理，进行了多种保护渣在感应电炉内的侵蚀试验，结果表明，随着保护渣粘度的降低或「Ｆ－」含量的增高，ＺｒＯ２－石墨质耐火材料蚀损严重，ＺｒＯ２－石墨质耐火材料的 倾向可以用构成保护渣化学发的阴－阳离子引力Ｉ计算的碱度值Ｂｉ解释，通过对试验后试样显微结构的观察，发现保护渣中低粘性组分侵入砖组织，使ＺｒＯ２颗粒细碎化，促进ＺｒＯ２－石墨     

连铸结晶器用保护渣

1 同结晶器保护法有关的表面缺陷纵向表面裂纹一碳含量在0.08%～0.14%范围内的钢种特别容易出现纵裂纹.碳的影响归结于当δ铁素体在弯月面附近转变成奥氏体时产生相对较大的热收缩.它引起了凝固壳中的折皱.所以由此引起的结晶器/凝固壳缝隙不均匀,造成了局部热点.这些点集中了导致纵裂的拉伸应力.已证明由热撕裂形成的裂纹接近弯月面附近的凝固界面,这里的延性相当低.当凝固壳脱离(结晶器壁)时,其表面延性进一步逐渐降低.如果拉伸应力足够大,表层内裂纹随后可以扩展到上部冷却表面.     

保护渣对Cs137结晶器钢水液面检测的影响

宝钢圆／方坯连铸生产中,保护渣对Ｃｓ１３７结昌器钢水液面检测精度有很大影响,严重时会导致铸坯表面质量出现问题甚至漏钢。通过现场试验,定量分析了保护渣对Ｃｓ１３７钢水液面检测精度及钢水液面波动的影响,并提出了初步的解决方案。     

连续铸钢结晶器用保护渣

1 熔融组织和熔化速度 结晶器保护渣的熔化,特别是其熔化速度对保护渣性能有很大影响。结晶器保护渣的熔化决定着保护渣保证形成熔池稳定深度的能力,要求该熔池可以保证向结晶器—铸坯间隙提供适量连续的熔融保护渣。     

连铸结晶器保护渣的熔化

１保护渣熔化过程和机理保护渣在钢水面上形成了所谓粉渣层－烧结层－液渣层的三层结构。保护渣熔化过程为：（１）试样中有机物氧化（脱水和汽化）；（２）碳质料的燃烧损失，时间较长，说明了渣粒烧结和熔化过程的延缓程度，与渣内所含碳粒类型和数量有关；（３）熔化突...     

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。     

高速连铸用结晶器保护渣

概述了高速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原成分;总结顾高拉速结晶器用保护渣的研究现状。     

连铸中碳钢用CK—2保护渣的研制

中碳钢亦称裂纹敏感性钢,在加铸过程中容易产生铸坯表面纵裂纹等缺陷,使用性能合适的保护渣可以改善结晶器内初始坯壳的传热条件,控制表面裂纹的产生,介绍了研制武钢三炼钢厂中碳钢用保护渣的过程及裂纹控制效果,分析了保护渣使用过程的性能变化和渣膜微观结构。     

结晶器保护渣渣膜的研究

采用光学显微镜和扫描电镜对工业用结晶器保护渣渣膜进行了观测，结果表明，渣膜厚度约０．７～１ｍｍ基本结构有三层，两层结晶层，中间为玻璃层，某些情况下也呈玻璃与结晶交替排列的多层结构，厚度方向上Ｃａ的分布略有差别，一般中心偏高，但同时也发现局部有ＣａＳ富集或微气孔现象。     

马氏体不锈钢板坯连铸保护渣研制与应用

 由于钢种特点,连铸马氏体不锈钢板坯容易产生裂纹缺陷,影响生产节奏和修磨效率;同时,由于采用通用型保护渣,也无法针对马氏体不锈钢板坯质量问题做出进一步改进。因此,尝试马氏体不锈钢板坯连铸保护渣的国产化研制和使用,通过保护渣碱度、CaF等的不同范围与保护渣结晶、黏度性能的关系研究,确定采用高碱度、低黏度、高结晶性的保护渣设计原则,并由此得出了适应马氏体不锈钢板坯连铸的保护渣设计方案。实际使用过程中,板坯纵裂率下降幅度达到30%,证明了马氏体不锈钢连铸板坯保护渣设计和研制的合理性和可行性。     

耐候钢异型坯连铸结晶器保护渣性能优化研究

由于异型坯形状复杂,在浇注耐候钢的过程中,铸坯表面质量较差,并经常发生粘结漏钢事故。通过实验室研究和工业性试验相结合的方法,根据异型坯连铸耐候钢的特点,分析了耐候钢异型坯表面质量差和浇注过程中发生粘结性漏钢的原因,提出了异型坯连铸耐候钢保护渣优化设计思路,重点研究了协调保护渣润滑和传热性能的影响因素。根据研究结果配制的异型坯连铸耐候钢专用保护渣,大生产应用结果表明,连浇炉数达到10炉以上,未发生粘结漏钢事故,耐候钢异型坯表面质量也有了明显提高。     

Mould Powder Requirements for High‐speed Casting

Mould powders play an important role in the stability of the continuous casting process of steel. The main functions of mould slag (i.e. molten powder) are to provide sufficient lubrication and to control the heat transfer between the developing steel shell and the mould. Sufficient lubrication requires an undisturbed melting of mould powders and uniform infiltration of mould slag. Based on the casting practice in IJmuiden, it is found that these demands become even more important for the applied high casting speeds in thin slab casting at 5 to 6 m/min. At Corus RD&T, mould powders were characterised by X‐ray diffraction and subsequent fully quantitative Rietveld analysis. Additionally, the melting of mould powders has been studied in‐situ using high‐temperature X‐ray diffraction, to gain crucial knowledge about melting relations. Slag rims obtained from the thin slab caster mould were characterised using extended microscopic techniques in order to describe the mechanisms of rim formation and growth. Finally, slag films obtained after casting were characterised. As a result, not only the melting process of mould powder, but also the mechanism of formation and growth of slag rims is much better understood. This knowledge will be applied to define the demands on the composition and properties of mould powder for even higher casting speeds.     

武钢三炼钢连铸低碳钢用结晶器保护渣的研制

介绍用于武钢三炼钢厂板坯连铸低碳钢器保护渣的研制过程，包括实验室保护渣配方的确定，保护渣造粒，以及现场试验。叙述了保护渣使用情况，应用效果，分析了保护渣使用前后的性能变化。     

The Influence of Carbonaceous Material on the Melting Behaviour of Mould Powder

The melting behaviour of mould powder during continuous casting is an important consideration with respect to caster performance, production rate and steel quality. In this experimental study the effect of different carbonaceous materials on the melting characteristics of mould powders was evaluated. Using X‐ray diffraction, different types of carbon were quantitatively characterized in terms of their internal structure and reactivity experiments were conducted to investigate potential relationships between the structural morphology of carbons and their reactivity. High temperature microscopy and drip test experiments were then used to investigate the melting behaviour of mould powders containing different carbonaceous materials. From the results obtained, correlations were established between the structural factors, chemical reactivity and melting behaviour.     

Numerical Study on Mould Powder Entrapment Caused by Vortexing in a Continuous Casting Process

Unsteady three‐dimensional turbulent flow phenomena are seen to have a major impact on steel quality in the continuous casting process. Usually steel mould powder is placed on top of the mould in order to use it as a lubricant between the solidifying steel and the mould and to prevent heat losses from the molten steel. It is well known that mould powder entrapment into the molten steel lowers the quality of the final steel products significantly. This can be caused by a vortexing flow at the interface between mould powder and molten steel near the submerged entry nozzle (SEN). The paper describes a study which was performed to analyse if commercial Computational Fluid Dynamics (CFD) software is capable of predicting the transient build‐up of vertical structures in the casting mould. Two‐phase‐flow phenomena have been modelled by using the Volume Of Fluid (VOF) method. The influence of different turbulence models, mesh densities and initial as well as boundary conditions on the resulting flow field was investigated. Due to the size and complexity of the problems the simulations partially had to be performed in parallel mode on a Linux‐cluster computing environment.