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。     

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.     

活性石灰回转窑内衬复合砖的研制与应用

针对活性石灰回转窑在运行中存在内衬砖使用寿命短、隔热效果不好导致炉壳过热的问题,开展了回转窑内衬耐火材料的研究。通过破损调查和配方试验,研制了耐高温工作层与保温层一体成型的复合结构预制砖,使回转窑内衬的使用寿命提高到2年以上,降低炉壳表面温度50℃以上。     

钢包内衬用MgO-CaO-C砖的开发与应用

采用抗水化处理后的镁钙砂为原料 ,研制了MgO -CaO -C砖 ,并对使用MgO -CaO -C砖过程中钢液中夹杂数量和氧含量的变化情况进行了分析。结果表明 :MgO -CaO -C砖在钢包包壁非渣线部位使用 ,能减少钢中氧含量和夹杂物数量 ,降低夹杂粒径 ,改变夹杂粒度分布 ,提高钢水质量。     

Innovative Lining of Unburnt Al_2O_3-MgO Brick for 300t Steel Ladle in Baosteel

The manufacture of clean steel needs high performance carbon-free bricks for ladle lining.Based on long term application experiences of the prefab Al₂O₃-MgO blocks,unburnt Al₂O₃-MgO brick has been developed by pressing a mix of alumina,spinel and magnesia as major raw materials and Al₂O₃-MgO gel powder as binder.In addition to low open porosity and high strength,the unburnt Al₂O₃-MgO brick shows superior corrosion resistance and thermal shock resistance to the prefab block.Field trials in a 300t steel ladle have indicated the residual lining of unburnt Al₂O₃-MgO bricks showed smooth surface without large spalling and seldom steel infiltration,consequently longer service life than the prefab blocks.The reliable,unburnt Al₂O₃-MgO bricks have more advantages of high efficiency,energy-saving and eco-friendly production.It will be one of the best options for ladle lining in the manufacture of high-purity steel.     

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.     

Performance of a ceramic frit anti-oxidation coating on a MgO-C refractory brick

In steel production, ladles must be preheated to minimize the heat loss of the steel melt, prevent thermal shock of refractory bricks (MgO-C), and to maximize the lining life of ladle. Partial oxidation of MgO-C bricks begins in the graphite bond during the preheating. Oxidation of graphite bond also causes a decrease in performance of the bricks because of an increase in the brick porosity. In this article, coating on a MgO-C brick surface by a ceramic film to protect against carbon oxidation was studied. Coated and un-coated bricks were heated at 1200 °C, cooled to room temperature, then the brick properties investigated. The oxidization resistance properties of brick with coating were much better than those without coating, which should lead to longer refractory service life.     

低碳MgO-C耐火材料结构和性能优化的研究进展

MgO-C耐火材料作为钢铁冶炼用关键基础材料,被广泛用作转炉衬砖、电弧炉炉壁和钢包渣线用砖。寻求制备高性能低碳MgO-C耐火材料的新方法对耐火材料及冶金行业的发展至关重要,本文从纳米碳源的引入、骨料表面的改性和镁基骨料的引入、酚醛树脂的改性、抗氧化剂的引入及陶瓷相的原位形成角度出发,综述了改善低碳MgO-C耐火材料结构和性能的研究进展,以期为进一步推动低碳MgO-C耐火材料的发展提供参考,并对MgO-C耐火材料未来的研究方向进行了展望。     

Tests of olivinite-based ladle refractory brick

A lining of burned forsterite—chromite brick, with the olivinite mined at the Khabozerovskoe deposit as the base, was tested in the 385-ton steel-teerning ladle of the converter plant at the Severstal' Works. The brick was made by the method developed at the St. Petersburg Institute of Refractories. The characteristics of the brick are given. The ladle lining was tested on a wide range of converter steel grades. At the end of the service period, the lining was examined and the nature of its wear was identified. The experimental lining withstood 23 heats. It is thought promising to use refractory brick of the forsterite composition in large-tonnage steel-teeming ladles.     

Production technology for ladle brick using semiacid clays

Conclusions A technology was developed for making ladle brick from Ch1PK semiacid clays mined in the Chasov Yar area.The biggest difference between semiacid ladle brick and firebrick is the after-expansion at service temperatures of 1500–1600° C which reaches about 3% and which densifies the structure of the ladle.The life of semiacid brick in 250-ton steel ladles on average is 11% higher than ordinary ladle brick.The production of ladle brick from semiacid raw materials is economic. The lower cost of the product is a result of using cheaper raw materials and firing the clay into chamotte and products at lower temperatures.Translated from Ogneupory, No. 5, pp. 3–7, May 1967.     

微膨胀高铝砖的生产与应用

采用优质高铝矾土和莫来石合成料为主要原料,添加蓝晶石、红柱石、硅线石(简称三石)和叶蜡石等作膨胀剂,使用软质黏土作结合剂,再外加适量添加剂,经适宜温度焙烧制成高铝砖,并成功应用于冶炼低碳钢、不锈钢等钢包内村。该砖在高温区使用时产生微膨胀,使钢包内衬具有良好的整体性,从而提高抗侵蚀性。     

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.     

Design of Composite Ladle Shroud for Improving Thermal Shock Resistance

A ladle shroud is one of the functional refractories for continuous casting,which undergoes severe thermal shock by molten steel when used without pre-heating.The composite ladle shroud with an insulating liner presents excellent thermal shock resistance.Finite element simulation is an effective method to explore the maximum thermal stress for predicting the thermal shock resistance of ladle shrouds.In this paper,the influence of the lining materials and the structure of ladle shrouds on the thermal stress distribution is systematically researched.The working mechanism of the lining material on the body material is also presented.Lining materials with low thermal expansion,elastic modulus and thermal conductivity are helpful to improve the thermal shock resistance and an optimum lining thickness is suggested.The lining material can both serve as thermal resistance for the body material to buffer the thermal stress,and apply a strain load to the body material by the thermal strain to increase the stress.     

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。     

炉外精炼钢包渣线用MgO-C砖

精炼钢包渣线受到真空搅拌的强烈冲刷，炉渣的严重侵蚀和周期性热循环损伤，使用条件十分苛刻。采用优质MgO-C砖，使用效果良好。分析了影响精炼钢包使用的因素。     

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...     

铝镁尖晶石炭砖在盛钢桶上的应用

以铝镁尖晶石炭砖取代铝镁不烧砖在首钢第三炼钢厂９０ｔ盛钢桶上应用时效果良好．其侵蚀速率低，工作面反应层与变质层很薄，有较好的抗热震性能，尤其对抵抗碱性熔渣的侵蚀和渗透明显优于铝镁不烧砖。试验结果表明铝镁尖晶石炭砖的使用寿命比原用铝镁不烧砖提高一倍以上。     

Manufacture and testing of tar-bonded dolomite-magnesite brick

Conclusion The use of calcined dolomite powder without supplementary grinding, preprocessed with fused coal-tar pitch, for making unfired goods with a tar bond makes it possible to produce refractories with a high resistance to hydration and with other satisfactory properties.The testing of dolomite-magnesite brick with a tar bond in the lining of a ladle, imitating a converter with oxygen blow, showed that it had a high wear resistance; the wear intensity is no different from that of periclasespinel brick.Tarred dolomite-magnesite goods with metal cladding showing certain advantages in service over unclad products, need to be tested in large quantities, especially in the charging side and in the throat of the lining of the converter.To obtain data more reliably reflecting the life of dolomite-magnesite brick with a tar bond in converters working with oxygen, the authors should carry out repeat tests of these refractories in conditions excluding the long intermelting downtime-Editors.     

Increasing the life of steel ladle linings at the Cherepovets Metallurgical Factory

Conclusions A 4-stage lining was developed and introduced at the Cherepovets Metallurgical Factory for 300 ton steel ladles.As a result of introducing this lining and improving the quality of the brick the life of the ladle increased by 31% compared with that achieved in 1968.To ensure uniform resistance in the 4-stage lining over the height of the structure tests were made with a lining using semisilica brick based on Latnensk clay and Ovruch pyrophyllites in the upper and central belts of the structure. The use of the semisilica brick in place of the KShU-37 brick manufactured by the Borovich Refractories Combine increases the resistance of the lining in the ladles, and reduces the refractories consumption per ton of steel.Translated from Ogneupory, No. 4, pp. 22–25, April, 1971.     

Making ladle products using North Onezhsk bauxites

Conclusions It was found that the North-Onezhsk bauxites are promising raw materials for the production of highly resistant ladle bricks.We developed and mastered a technology in the BKO conditions for making ladle brick using these bauxites containing up to 6% iron oxides.In the lining of the steel ladles made with the use of bauxite chamotte, the bricks wear out 30–40% less than with ordinary ladle brick produced by BKO and the Chasov Yarsk Combine.Translated from Ogneupory, No. 8, pp. 4–9, August, 1980.