钢包透气砖的发展及其典型复合结构的损毁分析

Development of purging plugs for ladles and damaging mechanisms of typical composite structures

简要回顾了钢包透气砖材质更替和结构演变历程,列举了单一结构透气砖的性能缺陷。根据主要气道结构类型,将复合结构透气砖划分为弥散型、芯板型和陶瓷管型三大类,分析了各类复合透气砖的结构特征、性能特点和冶金功效。通过剖析服役后下线残砖,揭示了复合透气砖的典型损毁机制:钢液钢渣渗入弥散透气砖后堵塞贯通气孔,渗钢层被高压冲刷或氧枪烧蚀是弥散型复合透气砖的首要损毁机制;钢渣中CaO渗入刚玉-莫来石质芯板的基质中,与莫来石反应生成低熔点相,在氧枪冲蚀下逐渐蚀损,加速了芯板型复合透气砖的损毁;浇注本体的抗热震性差,频繁热冲击时砖体横向断裂,或者直通管渗钢,导致底吹失效或流量减小,是陶瓷管型复合透气砖的主要损毁机制。

The material replacement and the structure evolution of purging plugs for ladles were briefly reviewed,and the deficiencies of single structure plugs were listed.According to the main gas passage types,composited purging plugs were divided into three categories:dispersive,core-plate and ceramic-tube.Their structural characteristics,service performance and metallurgical efficiency were compared.By analyzing the used purging plugs,the typical damage mechanisms of composited purging plugs were revealed.(1)The chief damage mechanism of dispersive composited purging plugs is that liquid steel slag penetrates and blocks the through pores,then the penetration layer is eroded by the high-pressure argon or ablated by the oxygen lance.(2)CaO from steel slag infiltrates the matrix of corundum-mullite core plate,then reacts with mullite to form low melting point phases.The eroded core plate damage is accelerated under oxygen cleaning.(3)Due to the poor thermal shock resistance of the body material,transverse fracture of the plug occurs under frequent thermal shock,or the steel infiltrates the straight tube,resulting in the failure of bottom blowing or the flow reduction,which are the key damage mechanism of ceramic-tube purging plugs.