钢液对连铸用含碳耐火材料的侵蚀作用研究

采用中频炉的实验室模拟试验(试验条件:钢液温度1600℃,浸入时间30min,气氛分别为空气和真空)和通过对用后耐火材料的显微结构分析,研究了钢液对3种连铸用含碳耐火材料(Al2O3-C、MgO-C和ZrO2-C)的侵蚀作用。结果表明,脱碳层的形成及钢液中夹杂物与脱碳层中耐火氧化物的反应是材料蚀损的主要原因。因此,在含碳耐火材料接触钢液的表面形成致密耐火层,能有效抑制钢液对连铸用含碳耐火材料的侵蚀。     

Development of Refractories for Continuous Casting

The paper introduces refractories for continuous casting,especially,refractories for continuous casting for clean steel in baosteel.Developing direction of refractoies for continuous casting has been pointed out to satisfy the new metallurgical operating practice.     

Structure and Material Design of High Performance Functional Refractories for High-speed Continuous Casting

Functional refractories,including submerged entry nozzle ( SEN) ,ladle shroud and monolithic stopper, are the key refractories for continuous casting. Driven by the demand of high-speed continuous casting,traditional functional refractories fail to meet the needs of long span life,and high performance functional refractories for continuous casting are increasingly required. Through structure and material design,the performance of functional refractories is significantly improved. In this paper,some research advances on functional refractories for continuous casting were mentioned. Through numerical modeling and hot simulation,the service life of non-preheating ladle shroud was increased from 8 h to more than 12 h. Through the water modeling,the flow patterns in the mold were significantly improved and through hot simulation and material design,the service life and reliability of SEN were also significantly improved.     

High Chrome Containing Refractories for Coal Slurry Gasifier

Water, oxygen and coal are converted into CO, H2, methane in the coal slurry gasifier. Under the condition of high temperature and high pressure, high chromecontaining refractories are used as hot face lining. The collapse of refractories from corrosion and spalling is mainly attributed to liquid deslagging. Refractories for coal slurry gasifier, destruction mechanism and solutions are analyzed.     

镁钙耐火材料与钢水作用的热力学研究

通过扫描电镜能谱分析,研究了镁钙耐火材料与ARO16钢的作用,通过热力学数据,结合试验结果,进行了热力学研究,结果表明:含游离CaO的镁钙耐火材料在1600℃下与ARO16钢发生作用,在耐火材料表面形成反应层,推测有CaS、3CaO·Al2O3、CaO·Al2O3、CaO·2Al2O3、CaO·6Al2O3、3CaO·SiO2、2CaO·SiO2、3CaO·2SiO2、MnO、FeO等物质生成.     

含碳耐火材料的耐蚀性评价方法

介绍了采用回转侵蚀法，对以MgO—C砖、从Al2O3—C砖为主的含碳耐火材料的耐蚀性进行试验时。通过在试样内面组装钢管作为保护板。在从常温升到试验温度期间，将外部气体与试样之间加以物理遮断。能够抑制碳在升温过程中的氧化。从而确立了高精度评价含碳耐火材料抗炉渣侵蚀性的方法。     

板坯连铸电磁制动下结晶器内金属流场的研究

以水银为实验工质,通过物理模拟实验研究电磁制动下,板坯结晶器内钢水流动规律. 实验通过超声多普勒测速仪获取不同电磁制动方式[单条型电磁制动(EMBr-Ruler)和流动控制结晶器(FC Mold)]、水口浸入深度和结晶器宽度下的液流特征. 结果表明,在EMBr-Ruler或FC Mold II电磁制动下,结晶器窄壁处形成"液流通道",不利于结晶器内快速形成向下的活塞流. 水口出口距下区磁场越近或被磁场所覆盖,则通道效应减弱; 结晶器宽度增大,亦可降低该通道内液流的冲击效果. FC Mold II下,液面流速和湍流度比EMBr-Ruler时低[液面水平流速最大值分别为0.155 (Case 1)和0.134 m/s (Case 2)],且加大水口浸入深度,可降低液流撞击结晶器窄壁的水平流速[其最大值0.071 (Case 2)和0.068 m/s (Case 3)]. 结晶器宽度的变化不改变水口浸入深度对结晶器流场的影响规律.     

板坯连铸中电磁制动方式对结晶器中钢液流场的影响

以水银模拟钢水,研究了板坯连铸电磁制动过程中不同拉速下,不同电磁制动方式[单条型电磁制动(EMBr-Ruler)和流动控制结晶器(FC Mold)]对结晶器内钢水流动的影响规律. 实验表明,(1) FC Mold可有效抑制结晶器内液面流及其波动行为(拉速0.52 m/min时最大液面流速和湍流度分别为无电磁制动时的1/5和1/6); (2)两种电磁制动方式均会压缩水口出流的扩张空间,结晶器窄壁附近向下液流的竖直流速剧增[拉速0.41 m/min时最大竖直流速由0.030 m/s(无电磁制动)增至0.066 (EMBr-Ruler)和0.057 m/s (FC Mold)],不利于快速形成活塞流;(3)高拉速(如2.0 m/min)时FC Mold电磁制动可获得较好的流场形态(液面最大流速为0.028 m/s),中拉速(如1.3 m/min)时EMBr-Ruler电磁制动所得流态较好,而低拉速(如1.0 m/min)时2种电磁制动方式均未获得预想的效果,甚至会恶化结晶器内原有的流态.     

连铸用功能耐火材料的发展

新的冶炼技术和连铸新工艺的发展使连铸用功能耐火材料面临前所未有的挑战。研制开发多功能、高性能和长寿命的连铸用耐火材料是今后主要的研究课题。本文讨论了影响浸入式水口、长水口及整体塞棒使用寿命的主要因素 ,并阐述了改善性能、延长使用寿命的措施     

Recent Progress of Carbon Nanotubes Reinforced MgO-C and Al_2O_3-C Refractories

Carbon nanotubes （CNTs） have been extensively studied over the last two decades since they possess excellent properties.CNTs have been considered as new promising reinforcements for carbon containing refractories （CCRs）.Current research progress of the CNT-reinforced MgO-C and Al2O3-C refractories was summarized in this mini-review,and the CNT-reinforced CCRs possess remarkable mechanical properties and superior thermal shock resistance compared to CCRs without CNTs.     

Effect of Alkalies and of a Reducing Atmosphere on the Corrosion of Refractories by Molten Aluminum

The corrosion of aluminosilicate refractories by molten aluminum, such as in melting and holding furnaces, generally leads to the formation of an alumina deposit on the refractory. In the presence of alkalies and under a reducing atmosphere the extent of corrosion is increased. This could be related to the transformation of the alumina to sodium aluminate, whose formation kinetics are increased under a reducing atmosphere, promoting the formation of aluminum nitride. In melting and holding furnaces, the alkalies could originate from the presence of a cryothic bath in the metal charge and/or from the refractories. In the latter case, it was shown that aluminum nonwetting refractory castables containing aluminum fluoride as the nonwetting agent could lead to severe corrosion in the above applications if their alkali content is such that it promotes the formation of β-alumina.     

Damage Mechanism and Countermeasures of Carbon Bonded Refractories for Continuous Casting

The long nozzle,stopper,and submerged entry nozzle play an important role in continuous casting. They are of the similar composition and are mainly damaged by liquid steel thermal shock which leads to immediate cracks or fracture in their combined area because of the thermal mechanical properties mismatch,or damaged by corrosion on their interface. The failure mechanisms are the thermal shock damage and continuous reaction corrosion. High efficiency and long life of the long nozzle,stopper,and submerged entry nozzle can be realized by optimizing the thermal mechanical properties,the key erosion step,and the combination match.     

提高熔铸耐火材料制品冒口补缩效率途径的探讨

通过分析熔铸耐火材料制品冒口的补缩原理和冒口的设计,认为浇铸冒口是浇铸工艺的重要组成部分,为提高熔铸耐火材料制品冒口补缩效率提出:合理加高冒口,提高冒口内熔液的补缩压力;采用加热冒口,延长冒口的凝固时间;实行二次补浇铸,增加冒口热能;控制制品铸件保温工艺,增长冒口补缩距离。     

Roles and Progress of Refractories for Clean Steel Technology

This paper presents a general survey of roles and progress of fundamental and functional refractories applied in secondary steelmaking, tundish and mold metallurgy along with the evolution of clean steel technology,focusing on refractories that are to create clean environments, benefit cleanliness and productive efficiency for the clean steal production, in particular, reducing the total oxygen content and inclusion defects in steel. All that arguments have revealed in abundant that the interaction between ...     

导电耐火材料及其常温电阻率测试仪的研制

简要介绍了直流电弧炉用导电耐火材料的理化性能及导电机理 ,根据其导电特性研制了导电耐火材料用常温电阻率测试仪 ,介绍了电阻率测试仪的结构及特点     

薄板坯连铸结晶器内钢液流动与传热及凝固耦合的数值模拟

针对断面为135 mm×1200 mm的薄板坯连铸结晶器,建立了4孔浸入式水口下薄板坯连铸结晶器内钢液流动、传热和凝固耦合的三维数学模型,引入F数评价薄板坯连铸结晶器内液面波动情况,分析结晶器内钢液流动、温度分布及凝固坯壳厚度的变化情况. 结果表明,用F数评价薄板坯连铸结晶器内液面波动可行,拉速由1.44 m/min增加到1.80 m/min时,钢液液面波动的F数由1.05增加到2.55,凝固壳厚度(dshell)与凝固时间(t)满足关系式dshell=18.92t1/2?1.05,模拟结果与文献实验结果基本一致.     

Effect of Zircon Addition on Properties of Low Carbon Al2O3-C Refractories

Using tabular alumina as aggregate,tabular alumina fines, reactive alumina ultra-fines, aluminum powders,silicon powders,carbon black,flake graphite,B4C and zircon fines as matrix,low carbon Al2O3- C refractories were prepared. Influences of zircon powders additions( 0,3%,5% and 7%,in mass,the same hereinafter) on properties,phase composition and microstructure were investigated. The results show that the ZrO2- nitride can be in-situ formed through carbothermal reduction and nitridation in Al2O3- C refractories.With the increase of zircon powder,the oxidation resistance of the Al2O3- C refractories improves obviously,the oxidized layer thickness decreases from 7. 94 mm without zircon to 2. 71 mm with 5% zircon. HMOR at 1 400 ℃of the Al2O3- C refractories reaches the maximum 14. 9MPa when zircon addition is 5%. With the increase of zircon powder,the apparent porosity and bulk density change a little,CMOR and CCS increase.     

板坯连铸结晶器内液面波动数值模拟

以某厂190mm×1700mm连铸结晶器为研究对象,采用商业软件Fluent,应用VOF模型对结晶器内钢/渣界面波动进行数值模拟,主要研究拉速、浸入式水口倾角及水口插入深度等工艺参数对结晶器内自由表面液面波动的影响,并用水模实验进行了验证.结果表明,随着拉速的增大,浸入式水口倾角向下减小及水口插入深度的减小,液面波动明显增大,靠近窄面附近的波动较为显著,液渣层覆盖不均匀.当插入深度在140~180mm之间变化时,钢/渣界面波动幅度不大.     

Selection of Refractories for the Funnel of Metering Nozzles Intended for the Continuous Casting of Steel

Refractories and Industrial Ceramics - We present a literature survey on the operation of tundishes and the possibility of continuous casting of steels in the “open start” mode. On the...