Abstract: In order to improve the thermal shock resistance of corundum castables for snorkels of RH furnaces,SiO₂ fume was added with different additions (0,0.1%,0.2%,0.3%,and 0.4%,by mass).The actual working condition was simulated,thermal shock was conducted by preheating and then dipping into steel melt,and the influence of the SiO₂ fume addition on the thermal shock resistance of the castables was investigated by XRD,SEM,and FactSage 8.0.The results show that:(1)the SiO₂ fume addition can improve the thermal shock resistance of the corundum castables for RH snorkels;with the SiO₂ fume addition increasing,the modulus of rupture retention ratio of the specimen under steel dipping thermal shock increases first and then decreases,reaching the maximum (60%) with 0.2% SiO₂ fume addition;(2)the mechanism that SiO₂ fume improves the thermal shock resistance of corundum castables for RH snorkels is as follows:after adding SiO₂ fume,the high temperature liquid phases such as nepheline and melilite formed in the matrix can buffer the thermal stress of the specimens caused by thermal shock under the steel dipping condition.

Key words: corundum castables, thermal shock resistance, silica fume, high temperature liquid phase

摘要： 为了提高RH炉浸渍管用刚玉浇注料的抗热震性,在其中加入不同量的SiO₂微粉(质量分数分别为0、0.1%、0.2%、0.3%、0.4%)。模拟实际工况,采用先预热后蘸钢的方法对试样进行热冲击,并利用XRD、SEM、FactSage 8.0等手段分析了SiO₂微粉添加量对浇注料抗热震性的影响。结果表明:1)加入SiO₂微粉可以改善RH炉浸渍管用刚玉基浇注料的抗热震性;随着SiO₂微粉加入量的增加,试样在蘸钢热震条件下的抗折强度保持率呈先增大后减小的变化趋势,SiO₂微粉加入量为0.2%(w)时抗折强度保持率达到最大值60%。2)SiO₂微粉提高RH炉浸渍管用刚玉基浇注料抗热震性的机制为:加入SiO₂微粉后,基质中生成的以霞石、黄长石为主的高温液相,缓冲了试样在蘸钢热震条件下的热应力。

关键词: 刚玉浇注料, 抗热震性, SiO₂微粉, 高温液相