Abstract: Calcium hexaaluminate (CA₆) castables have broad application prospects in extreme working conditions of high-temperature industries due to their excellent mechanical properties,corrosion resistance,and low thermal conductivity.CA₆ castables with different pore-forming methods (particle packing,foaming method,and adding alumina hollow spheres) were placed in a steel rolling reheating furnace and operated for 10 months.The changes in bulk density,apparent porosity,strength,and microstructure were focused on for comparative analysis.The results show that after 10 months of service in the steel rolling reheating furnace,the bulk density of the CA₆ castables with different pore-forming methods has no obvious difference compared with that of castables after holding at 1 300 ℃ for 3 h in a test box furnace;the apparent porosity of all castables increases,among which the particle packing pore-forming specimen increases the most;the cold crushing strength of all castables increases,and the largest increase is in the group adding alumina hollow spheres (from 99.5 MPa to 137.3 MPa);the average pore size of the castables tends to increase,and the pore size distribution of the castable adding alumina hollow spheres changes the least.

Key words: CA₆ castables, durability, mechanical properties, microstructure

摘要： 六铝酸钙(CA₆)浇注料因其兼具优良的力学性能、抗侵蚀性和较低的热导率在高温工业的极端工况环境下有着广泛的应用前景。将不同造孔方式(颗粒堆积、发泡法和添加氧化铝空心球)的CA₆浇注料置于轧钢加热炉内随炉运行10个月,重点对比分析了其体积密度、显气孔率、强度和显微结构的变化。结果表明:不同造孔方式的CA₆浇注料在轧钢加热炉内服役10个月后,与在试验箱式炉内1 300 ℃保温3 h相比,其体积密度无明显差异,显气孔率均增大,其中增加最多的为颗粒堆积造孔试样;常温耐压强度均增加,其中增大幅度最大的为添加氧化铝空心球组(由99.5 MPa变为137 MPa);浇注料的平均孔径均有增大趋势,其中添加氧化铝空心球浇注料的孔径分布变化最小。

关键词: 六铝酸钙浇注料, 耐久性, 力学性能, 显微结构