Chinese Standards on Refractories Purging Plugs and Well Blocks for Refining Ladle

1 Scope This standard specifies the classification,technical requirements,test methods,inspection rules,marking,packing,transportation,storage and quality certificate of purging plugs and well blocks for refining ladle. This standard is applicable to the directional slit purging plugs and well blocks for refining ladle.     

用后钢包透气砖显微结构分析

对60 t LF VD精炼钢包用刚玉-尖晶石透气砖和45 t LF精炼钢包用铬刚玉-尖晶石透气砖用后残砖进行了显微结构分析。结果表明:LF精炼工艺用透气砖狭缝及裂纹有明显的渣侵蚀和渗透,LF VD精炼工艺用透气砖狭缝和裂纹有钢液渗透。在周期性操作过程中,狭缝口部的扩大和热震造成的裂纹会使钢液或渣液的渗透侵蚀作用加剧并导致剥落现象的发生。透气砖狭缝堵塞直接影响吹通率和使用寿命,所以,要优化狭缝尺寸,提高材料的抗热震性。     

电熔镁砂加入量对钢包用铝镁质透气砖性能的影响

为了实现钢包用透气砖的无铬化,以板状刚玉(6～3、3～1、≤1mm)为骨料,板状刚玉细粉(≤0.044mm)、α-Al2O3微粉(≤5μm,d50=2.01μm)、镁铝尖晶石细粉(≤0.044mm)、电熔镁砂细粉(≤0.044mm)为基质,以纯铝酸盐水泥为结合剂,将骨料和基质的质量比固定为70:30,通过研究电熔镁砂细粉加入量(其质量分数1％、2％、3％、4％、5％)对铝镁质透气砖性能的影响,研制了铝镁质透气砖,与铬刚玉质透气砖的性能进行了对比.结果表明:加入质量分数2％的电熔镁砂细粉,试样的力学性能提高,抗热震性增强;进一步增大电熔镁砂细粉的加入量,由于原位镁铝尖晶石的生成量过多,微裂纹发展成为破坏性裂纹,试样的强度急剧降低,体积密度下降,试样的加热永久线变化增大,抗热震性先增强后减小,高温抗折强度下降.通过铬刚玉质透气砖和铝镁质透气砖性能及现场试用情况的对比,认为铝镁质透气砖可代替铬刚玉质透气砖使用,实现透气砖的无铬化.     

供气元件在炼钢工艺中的应用

对炼钢生产的整个过程中使用的供气元件进行了全面介绍。由于使用条件不同 ,各工艺使用的供气元件的种类、结构、材质等也呈现不同的特点 :目前转炉底吹用透气砖多为镁炭质高压成型分段组合式透气砖 ,以满足高寿命要求 ;电炉底吹系统存在直接搅拌与间接搅拌两种形式 ;供气元件在钢包中的应用最广泛 ,为铬刚玉质和刚玉 -尖晶石质及非氧化物结合刚玉质狭缝型或芯板组装式透气砖。此外 ,供气元件在中间包、鱼雷罐车及连铸水口上的应用也日趋广泛 ,并将随着钢铁工业技术的进步得到更广泛的应用     

狭缝对透气砖热应力影响的模拟研究

对透气砖吹氩时热应力模拟计算,探索狭缝对透气砖热应力影响,寻求合理的狭缝布置提高透气砖使用寿命.首先,在保持固定的狭缝尺寸与位置的前提下建立径向与切向两种狭缝布置形式钢包透气砖物理模型,然后设置合适的边界条件,计算在吹氩时两种模型整体应力及轴向不同位置路径热应力分布.研究发现:两种狭缝形式的透气砖在工作面附近都有明显应力梯度;狭缝径向布置与切向布置时轴中心区域在相同路径上应力最大值比较,前者是后者的3到6倍;切向狭缝截面中心呈现较低应力,狭缝至截面边缘的区域应力较高,而狭缝径向布置时截面上狭缝之间的位置呈现出一个应力较高的环形区域.     

狭缝式透气砖的研制与应用

采用高性能铬刚玉质浇注料 ,通过合理的狭缝设计 ,研制了狭缝式透气砖。该砖具有吹成率高、寿命长、安全可靠等优点 ,适用于大型精炼钢包     

Effects of cement content on the microstructural evolution and mechanical properties of cement-bonded corundum castables

The cement-bonded corundum castables are often subjected to great temperature gradient in the service process of purging plugs for refining ladle. The mechanical properties of such castables are of particular interest in the serviceability and the safety of purging plug, which are significantly influenced by the microstructures including the amount, size and morphology of materials. The reported cement contents in compounds of purging plugs are generally low or ultralow, which inevitably limits the adjustable range of the mechanical properties enhancement by regulating their microstructures. In the present research, a serial of comprehensive experiments have been carried out, including the high cement contents (10–15 wt%), so as to further understand the role of cement content on the microstructural evolution and mechanical properties of castables. It is found that the phase compositions and microstructure can be optimized through adjusting the cement content in corundum castables. When the cement content is below 10 wt%, the hexagonal flake CA₆ grains are platelet-shaped both in the matrix and at the border of the aggregates, their amount and size increase and distributions are more uniformly with cement content. When the cement content is above 10 wt%, small amount of granular crystals CA₂ are detected in matrix, and CA₆ crystals transform to equiaxial morphologies after cement content of 10 wt%. This research also provides quantitative relationship between the mechanical properties of the castables and the cement content. Castables with cement content of 10 wt% contain most hexagonal flake CA₆ crystals, so that they have the highest CMOR and HMOR after heating at 1600 °C. However, CMOR decreases after cement content of 10 wt% due to the porosity and volumetric expansion from the formation of in-situ CA₆ and CA₂.     

Alumina-spinel castable for steel ladles: An overview

Alumina-spinel castable has excellent refractory properties, including high volume and thermal stability, good hot strength, and excellent resistance against corrosion, erosion, and thermal spalling. Excellent refractory properties have made it a preferred lining for steel ladles, reducing the erosion and corrosion of molten metal and slag and improving the ladle life and efficiency for decades. These castables are also significant for the replacement of chrome-bearing refractories that cause several health hazards. The current review paper covers preformed and in situ spinel containing alumina castables. It focuses on the importance of these castables in the sidewall and bottom portion of the steel ladle in detail, the effect of spinel and MgO content, and the factors affecting castable properties. The review also covers the final properties of castable and the application areas of alumina-spinel castable in steel ladle, purging plugs, and RH-degasser.     

CaCO3微粉对刚玉质弥散型透气砖性能的影响

弥散型透气砖因具有供气可靠性好、安全性高和精炼效果好等优点得到较多应用,然而其自身多孔结构导致的强度低和使用寿命短等缺陷限制了它的应用。为优化刚玉质弥散型透气砖的使用性能,本文以电熔白刚玉颗粒及细粉、α-Al₂O₃微粉、Cr₂O₃微粉等为主要原料,固定颗粒与细粉的质量比为85∶15,分别用质量分数为0%、1%、2%、3%的CaCO₃等量替代电熔白刚玉细粉,探索CaCO₃微粉的引入对弥散砖性能的影响。结果表明:随CaCO₃微粉加入量增加(0%~2%),弥散砖材料常温强度和高温强度增加,由于CaCO₃分解生成的CaO与基质中的Al₂O₃反应生成六铝酸钙,其相互穿插连接增加了基质间的结合程度,从而提高了材料的强度。     

精炼条件对狭缝式透气砖使用效果的影响

对狭缝式透气砖在大型精炼钢包中的损毁原因进行了分析,热应力和强大的冲刷磨损作用是两个主要因素.对狭缝式透气砖使用中影响其透气性能的各种因素加以分析后认为,除了透气砖本身狭缝的尺寸、钢水温度、钢水种类外,操作过程和使用中受保护的程度也是影响透气性能的重要因素.     

精炼钢包刚玉基耐火材料冲蚀的有限元分析

本文根据精炼钢包耐火材料的使用工艺条件,采用Johnson-cook模型,通过与实验值的对比,利用有限元模拟方法计算了刚玉基耐火材料在高温服役条件下的冲蚀率,研究了冲蚀角、冲蚀物速度、冲蚀物粒径和材料气孔率与冲蚀率之间的关系.结合耦合固液传热的精炼钢包钢液流场,对钢包精炼过程的冲蚀情况进行了分析和探讨.结果表明:采用Johnson-cook模型模拟高温条件下耐火材料以塑性切削为主的冲蚀,模型正确、参数合理;冲蚀角在15°～30°小角度范围内,冲蚀率较大,随后随着冲蚀角的增大而下降;冲蚀率与冲蚀物速度、冲蚀物尺寸、气孔率均呈现指数变化关系;精炼钢包刚玉基耐火材料主要是承受小角度切削冲蚀,服役过程中形成高熔点致密界面层能有效改善其抗冲蚀损毁.     

Ongoing Technology and Developing Trend of Ar-blowing Purging Plug

An introduction of the ongoing technology of ar-gon-blowing purging plugs in China was presented in this work.Gel powders were used as starting materials to enhance the high temperature mechanical properties of the purging plugs.Composite purging plug adopting ex-trusion formed gas-purging bar and slit had its surface structural design improved,which enhanced the resist-ances to thermal shock and molten steel penetration,prolonging the service life.In addition,the safety Was greatly improved by upgrading the framework and pro-duction process,enhancing the resistance to breakout.It is indicated that the developing trend is to produce pur-ging plugs of longer service life and better gas purging rate with different starting materials and structure de-signs to meet the requirements of various metallurgical processes.     

钢液脱氧工艺的发展状况分析

介绍了各种钢液脱氧工艺的发展过程及氢气、天然气脱氧和固体电解质脱氧等新型脱氧工艺的研究现状.采用氧化物冶金技术,控制钢中氧化物夹杂物的类型、尺寸和分布,以提高钢的焊接等性能已成为现行脱氧工艺研究热点:随着炉外精炼工艺的发展,钢包精炼中的扩散脱氧已成为生产低氧钢的一个重要途径.新型脱氧工艺中,脱氧产物不污染钢液的脱氧方法将成为未来的发展方向.     

洁净钢炉外精炼与连铸用耐火材料及其发展

简述了洁净钢炉外精炼与连铸用耐火材料的现状及发展方向,主要介绍了精炼钢包系统、RH精炼系统、中间包系统用耐火材料的材质选择及技术进步,同时强调了耐火材料的管理及创新在洁净钢生产中的作用。     

再生镁碳砖和铝镁碳砖在精炼钢包上的应用

介绍了采用64%～88%质量分数的用后钢包再生料制造的再生镁碳砖和再生铝镁碳砖的性能以及在精炼钢包上的应用情况。使用结果表明,根据使用条件和再生料的特点,把镁碳砖的制造技术和使用条件结合起来设计制造的再生镁碳砖,其使用效果显著好于原镁碳砖:在300 t精炼钢包渣线上的使用寿命提高15%,在50 t LF-VD炉渣线上的使用寿命提高50%以上。     

60t精炼钢包滑动水口的开发与应用

介绍了烧成铝炭滑板的生产工艺及其和ＹＨＫ－Ⅱ型滑动机构在６０ｔ精炼钢包上的应用。实践证明,精炼钢包采用铝炭滑板及ＹＨＫ－Ⅱ型滑动机构,能够大幅度降低事故率     

Production of porous ceramic plugs for blowing steel with gases through the ladle bottom

Conclusions We developed a technology for the production of porous plugs on the basis of fused magnesite and electrofused corundum. Through the plugs, it is possible to blow the metal 15–20 min after pouring the metal in the ladle. The life of the plugs is 4–5 blows.It is desirable to organize the production of porous plugs in one of the refractory plants.Translated from Ogneupory, No.1, pp.11–15, January, 1967.     

钢包用轻重质复合保温砖的研究与开发

精炼钢包永久衬用轻重质复合保温砖的重质部分相当于高铝砖，轻质部分相当于粘土质隔热砖。实际使用表明，采用轻重质复合保温砖作钢包永久衬，节能效果明显．可以获得显著的社会经济效益。     

改质剂对LATS精炼钢包渣粘度的影响

为减少LATS合金化精炼钢包浸渍罩粘渣,研究了LATS精炼前后钢包渣粘度的变化,并分别用CaO+CaF2, CaO+B2O3及Li2O作为钢包渣的改质剂来降低渣粘度. 采用旋转柱体法的粘度测试结果表明,LATS合金化精炼钢包渣的粘度高及LATS处理后渣的粘度进一步升高是造成浸渍罩粘渣的主要原因之一. 实验所用3种改质剂均能有效降低钢包渣的粘度. 在1500℃无改质剂时LATS处理后钢包渣粘度为6 Pa×s,当加入10% CaO+CaF2后渣粘度低于3 Pa×s,而加入10% CaO+B2O3或加入4% Li2O都可使渣粘度低于2 Pa×s.