Use of unfired periclase-carbon refractories in parts of linings of 350-ton steel-teeming ladles

Workers of the Azovstal’Company have established the causes of the decrease in the endurance of slag-line areas of linings of 350-ton steel-teeming ladles. In 1995–1996 they conducted industrial tests and introduced a process for lining the slag areas of 350-ton teeming ladles with unfired periclase-carbon refractories. The mean service life of a lining of a 350-ton teeming ladle with a slag line made of periclase-carbon refractories amounts to 23 heats on the average without hot repairs of the slag line during the campaign. The wear of the periclase-carbon lining in the slag line is 3.6–4.3 mm per heat. The specific consumption of refractories and materials for a lining has been decreased by 0.6–0.8 kg per ton of converter steel. Such an operating capacity for the periclase-carbon refractories in slag lines is provided by the composition and structure of the refractories, which possess a high heat resistance and resist the effect of the molten metal and slag. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 37–39, February, 1998.     

Service of refractory concretes in the lining of steel-teeming ladles

Conclusions An investigation of the temperature and slag regimes of concrete linings has shown that one half of the lining's thickness, the one on the metal melt side, is subjected to severe cyclical changes in temperature, whereas the other half operates under steady thermal conditions throughout the furnace campaign.It has been established that cooling of the lining with water sharply reduces the temperature of the contact layer of the lining, i. e., it leads to thermal shock with accompanying crack formation.The durability of the lining is largely determined by the correspondence of the chemical nature of the lining material with the chemical composition of the slags. Under the influence of converter slag with a basicity of 3,1–4.5, the rate of transfer of SiO₂ from the acid lining to the slag increases by 2–3 times in comparison that observed for slag with a basicity of 2.5–3.35. This in tarn leads to more intense decrease in the basicity of the ladle slag, enhancing its fluidity and causing intense wear of the lining in the lower sector of the ladle.The results of industrial tests showed that the most agressive effect on an acid lining is exerted by fluid slags with a basicity of 2.1–2.7. Slags of lower basicity are more viscous and closer in chemical composition to that of the lining. Slags of higher basicity have a higher viscosity and their penetrative power is therefore less.Translated from Ogneupory, No. 7, pp. 28–33, July, 1979.     

不锈钢冶炼用铁水包Al2O3-SiC-C内衬砖的性能与侵蚀机理

铁水包内衬材料长期服役于间隔周期较长的高、低温交替环境,极易发生剥落与侵蚀损毁。为了探索影响铁水包内衬材料使用寿命的主要因素,对市面上四种铁水包Al₂O₃-SiC-C内衬砖的化学成分、物相组成、物理性能和微观结构进行了分析,并以高炉渣为侵蚀介质,重点研究了不锈钢冶炼用铁水包Al₂O₃-SiC-C内衬砖的侵蚀机理。结果表明:铁水包Al₂O₃-SiC-C内衬砖中Al₂O₃含量越高,高温下制品的液相量越低,越有利于提高耐火砖的高温力学性能;随着含碳量的增加,铁水包Al₂O₃-SiC-C内衬砖的抗渣性得到明显改善,但抗氧化性及高温抗折强度呈下降趋势;高炉渣中CaO、MgO向耐火砖中渗透,与耐火砖中的Al₂O₃、SiO₂发生反应形成高熔点的镁铝尖晶石及低熔点的钙长石等,生成的低熔相会加剧耐火砖的侵蚀。     

加废钢条件下铁水包的异常侵蚀与用材问题探讨

对铁水包的异常侵蚀进行了调研,对铁水包用砖的性能、组成与结构进行分析.结果表明:1)铁水包包壁采用的铝碳化硅碳砖与包底用铝碳化硅碳砖不同,含较多的叶蜡石,Al2O3含量只有36.32％(w);体积密度、显气孔率、耐压强度均低于行业标准的要求;其抗氧化性差,使用过程中氧化形成多孔层,造成砖衬结构疏松,引起断砖、局部磨损及...     

宝钢300t钢包粘渣的原因及对策

介绍了宝钢３００ ｔ 钢包在使用中粘渣的情况，分析了钢包粘渣的原因。特别针对近来钢包超重非常严重的状况，在调查研究的基础上提出了一些措施，但从长远来看，要解决此问题必须根据宝钢的使用条件深入研究渣和耐火材料的反应机理，使耐火材料更好地适应炼钢生产的要求。     

Mixtures of a base composition: Consumable lining of tundish ladles of continuous casting machines

Work on creating a refractory mixture of a base composition for consumable linings of tundish ladles of continuous casting machines is described. Various binders for mixtures deposited on the working lining of the tundish ladle by guniting have been tested. The endurance of a consumable lining based on periclase with an elevated content of CaO was 5 heats on a CCM of an electric steelmaking shop.Translated from Ogneupory, No. 4, pp. 28 – 30, April, 1996.     

Increasing the endurance of the converter lining

A brief review of the expertise in increasing the endurance of the lining for converters gained at the West Siberia Iron and Steel Works (WSISW) is given. Within three years after the WSISW oxygen converter shop has been put in service, the lining endurance could be improved to 728 heats (1.8 times the design endurance). A flame gunning technology has been developed, which made it possible to achieve an endurance of 1300 heats (at a maximum of 2500 heats). A technology for repairing the converter lining by applying a slag coating (scull) in the stream of an inert gas has been developed. The combined effect of these two technologies made it possible, in 2003, to achieve an average endurance of 2476 heats (at a maximum of 4500 heats).Translated from Novye Ogneupory, No. 6, June, 2004, pp. 7–10.     

Testing ladle brick made by various factories

Conclusions The resistance of linings in steel-casting ladles depends on the working conditions and the construction of the lining, the quality of the brick laying during repairs of the working layer, and the resistance of the ladle brick. The greatest effect on the wear of the lining in ladles is exerted by the following working conditions: chemical composition of the slag, temperature of the metal being cast, the dwell time of metal and slag in the ladle during one casting, the height of the slag layer in the ladle, the thickness of the lining in each belt of the structure. The quality of the structure in the ladles is mainly determined by the size of the joints, the care with which they are filled with mortar, uniformity of drying and warming-up of the ladles before filling them with metal.The resistance of the ladle brick depends mainly on the apparent porosity and nature of the pores and the concentration of fluxes and mullite in the brick.The highest resistance in service was shown by Zaporozh'e ladle brick made from Polozhe kaolin and having the lowest apparent porosity. The concentration of iron oxides in the brick was moderate, and on average equalled 1.39%.In terms of falling resistance the ladle brick of the remaining concerns can be placed in the following order: Chasov-Yar, Semiluks, Bogdanovich, Magnitogorsk, and Borovich.In order to increase the resistance of steel casting ladle linings it is necessary to increase the resistance of the ladle brick by reducing the apparent porosity, using raw materials with low concentrations of fluxes and improving the firing in order to obtain the maximum conditions of the ladle, reducing to a minimum the quantity of slag and reducing the casting time; to use a more rational thickness for laying the ladles over the courses, taking into account better use of their capacity.Translated from Ogneupory, No.5, pp. 27–32, May, 1970.     

A Technology for Production of Composite Refractory Materials for the Lining of Steel Ladles

Results of the testing of new refractory materials for the lining of steel ladles are reported. Refractories based on coarsely crystalline periclase (98% MgO) for the slag zone with an endurance of 55 – 60 heats and wear rate of 2.3 mm/heat were tested. For the bottom lining of the steel ladle, alumina-periclase-carbon refractories using fused or sintered alumomagnesian spinels are developed. Performance characteristics of the newly developed refractory materials are discussed.__________Translated from Novye Ogneupory, No. 1, pp. 6 – 9, January, 2005.     

Wear of the periclase-lime lining of steel teeming ladles in ladle desulfurization of steel

Conclusions Wear of a periclase-lime steel teeming ladle refractory lining is a complex physicochemical process in which it is practically impossible to distinguish a predominant elementary direction of action of the molten slag and metal.Replacement of liquid synthetic slags with solid slag-forming mixtures in ladle desulfurization of steel does not have a significant influence on wear of the lining working layer.An increase in the amplitude and number of thermal cycles significantly increases formation of cracks in the refractory lining and, consequently, accelerates its wear. An increase in temperature gradient within the refractory layer significantly increases crack formation.The presence of high-temperature contact of the periclase-lime lining working layer with strong deoxidizers accelerates its wear.Reduction of the magnesium and calcium of the refractories by the carbon of the binder under ladle service conditions may occur only with escape of gaseous CO through the reinforcing layer and the joints of the refractory lining in special gas escape holes in the ladle shell.Translated from Ogneupory, No. 3, pp. 33–36, March, 1993.     

Post-mortem analysis of MgO–Al2O3–C bricks containing bauxite used in steel ladle walls

A serious problem with integrated masonry linings ladle was that the ladle wall bricks were difficult to be partially replaced. Thus, the service life of the ladle was determined by the properties of ladle wall bricks. In this study, the new generation of MgO–Al₂O₃–C bricks with bauxite aggregates was tested in a ladle lining of an integrated steel ladle for 103 cycles, and the corroded microstructure of the used brick was investigated. A multilayered structure of bauxite aggregates could be observed in the used brick, which inhibited the slag penetration along the boundary of the magnesia aggregates and reduced the degree of the aggregates fall off from the used bricks. Besides, during the process of slag penetration, bauxite aggregates could melt into the slag, which increased the viscosity of the slag and weakened the penetration ability of the slag. The MgO–Al₂O₃–C bricks with bauxite addition could improve the service life of the ladle to a certain extent.     

含炭耐火材料表面防氧化涂料的试制

对炭复合耐火材料表面氧化过程及防氧化涂料的性能进行了试验。同时探讨了涂料的防氧化机理。实践表明，这种防氧化涂料，可在铝镁炭包村与渣线部位镁炭砖及铝炭浸入式水口和整体塞棒上使用，表面不氧化，提高了使用寿命。     

The Use of a Multiple-Purpose Lining of the Casting Ladle in an Integrated Steel-Processing Unit at the Oskol'skii Electrical Iron and Steel Works

A report is given on the production of periclase-carbon refractories using advanced technologies and raw periclase of different quality grade at the Semilukskii Refractory Plant Joint-Stock Company (SRP JSC). Refractories available from the SRP JSC were used at the Oskol'skii Electrical Iron and Steel Works JSC (OEISW JSC) to fabricate the multiple-purpose lining for casting ladles exploited in vacuum furnaces and integrated steel-processing units. The endurance of the lining for the walls and the slag zone of the casting ladle reaches 69 heats.     

AOD炉渣对MgO-C砖的侵蚀机理研究

不锈钢生产主要采用氩氧精炼(AOD)炉冶炼工艺,本文探究AOD炉渣对钢包内衬用MgO-C砖的侵蚀机理,为提高钢包内衬用MgO-C砖的使用性能和服役寿命提供理论支撑。结合FactSage6.2软件、X射线衍射(XRD)、场发射扫描电子显微镜(SEM)和能量色散光谱(EDS)等测试手段分析炉渣侵蚀后MgO-C砖的物相变化、显微结构和化学成分变化。结果表明,随着侵蚀反应的进行,方镁石逐渐被熔蚀,且逐步出现Ca₃MgSi₂O₈等低熔点物相,以及MgAl₂O₄等高熔点物相。AOD炉渣通过基质部分侵蚀渗透MgO-C砖,并与方镁石反应生成Ca₃MgSi₂O₈等低熔点物相,熔蚀方镁石;同时,方镁石边界处生成MgAl₂O₄,阻碍AOD炉渣对MgO-C砖的侵蚀渗透。     

Multifunctional Refractory-lined Vessel: Ladle Aggregate

A ladle primarily is a container used to transport molten steel from the steelmaking unit to the casting facility.The essential requirements are heat resistant,insulative and strong enough to hold molten steel up to 300 t,with a structure of multilayered refractory lining in a steel shell vessel.When a ladle is assembled with three-phase graphite electrodes,a ladle furnace forms,starting steel refining process with/without the vacuum tank degasser and RH circulating degasser,in order to meet the growing demand on high purity and higher quality steel.The working lining is under aggressive conditions that comprise the chemical reaction with molten steel,the severe corrosion of liquid slag,the disaggregation through oxidation,and the strong stress due to the impacting of the melts and gases and the effects of thermomechanical behaviors.Magnesiacarbon brick is one of the major materials,being indispensable for the slagline of a ladle furnace.Alumina-magnesiacarbon brick has played an important role to substantially increase the service life in the metal zone,from the early lining materials of high alumina and doloma bricks.The permanent lining must assume sufficient responsibility to allow finishing the process of the engaged charge in case of a failure in the working lining.The insulation layer must be as thin as possible in order to maximize the ladle’s capacity,and reduce the shell temperature for saving energy.In this issue,several integrant refractories are reviewed or investigated in order to compile a lining overview,and to contribute a prolonged service life under aggressive working conditions of the ladle furnace.     

钢包粘渣与包衬耐火材料

阐明了钢包粘渣与包衬耐火材料存在一定的关系 ,抗渣渗透性差、容易出现开裂的包衬耐火材料容易粘渣。为防止钢包粘渣 ,适于采用抗侵蚀性和抗渣渗透性优良的尖晶石砖、铝尖晶石 (或铝镁 )浇注料、低密度浇注料以及抗剥落性好的刚玉 -锆英石浇注料作包衬耐火材料     

Characteristics and cementitious properties of ladle slag fines from steel production

Ladle slag is a by-product from further refining molten steel after coming out of a basic oxygen furnace (BOF) or an electric arc furnace (EAF). Air-cooled ladle slag has a very large portion of fine particles due to the conversion of β-C₂S to γ-C₂S during the cooling process. X-ray diffraction (XRD) analysis of three ladle slag fine samples passing 100, 200 and 325 mesh indicates that the major mineral in ladle slag fines is γ-C₂S, which does not show cementitious property in water. Experimental results have indicated that ladle slag fines show significant cementitious property in the presence of an alkaline activator. The finer the ladle slag is, the better the cementitious property of the slag is.     

铝镁尖晶石炭钢包砖的研制

在高铝质材料基质中加入MgO粉,并添加适量的碳素材料及抗氧化剂,研制出了铝镁尖晶石炭钢包砖。该铝镁尖晶石炭砖质量稳定,在太钢第二炼钢厂70t钢包上使用两年多来,包龄基本上稳定在75次左右,并且使用过程中侵蚀均匀,与打结包相比,挂渣少,无剥落。     

300t精炼钢包温度场和应力场的有限元分析

在目前所用材质体系和砌筑结构的基础上,对精炼过程中的300 t精炼钢包剪切应力场、温度场和热应力场以及膨胀缝的最大接触应力进行了有限元研究.结果表明:在LF精炼过程中,渣线处的内衬砖最容易受冲刷和热应力的作用而损毁,需在保证良好抗渣性能的同时采用热膨胀系数低、抗冲刷性好的耐火内衬砖;膨胀缝的最大接触应力与膨胀缝的大小呈线性反比关系,以保持在0.8～1.8 mm之间为宜.     

RH真空处理过程中钢中氧含量预测模型

针对３００ｔ钢包ＲＨ真空处理低碳铝镇静钢的多次试验数据，建立了ＲＨ处理过程中钢中氧含量的定量预测模型，得到了钢中氧含量的预测公式模型综合考虑了纯脱气时间、真空室吹氩流量、钢水环流量、钢包渣中ＦｅＯ＋ＭｎＯ含量、钢包内衬材质等因素的影响，并对改进ＲＨ操作进行了讨论