Abstract: To improve the service life of uncooled corundum-based slide rail materials for steel rolling heating furnaces,TiN_x-Al₂O₃ materials were prepared with white corundum as the main raw material,and non-stoichiometric TiN_x(x=0.3,0.4,and 0.5) as the binder by spark plasma sintering at 1 350,1 400,1 450,1 500,and 1 550 ℃ for 15 h.The effects of the TiN_x additions (15%,20%,25%,30%,and 35%,by volume) on the relative density,cold compressive strength,wear resistance,refractoriness under load,thermal shock resistance,iron sensitivity,and corrosion resistance against iron oxide slag of the materials were investigated,and the results were compared with those of SiC-Al₂O₃ composites.The results show that:(1)when the heat treatment temperature is 1 450 ℃,the relative density initially increases and then stabilizes as the TiN_x addition increases;(2)when the TiN_x addition is 30%,with the increasing heat treatment temperature,the relative density,cold compressive strength,and wear loss initially increase and then stabilize,the refractoriness under load keeps at 1 800-1 900 ℃,while the number of thermal shock resistance cycles generally shows a declining trend;(3)under simulated working conditions of a steel rolling heating furnace (1 300 ℃,unsealed),the mass of the samples initially increases and then stabilizes with the prolongation of the holding time,and the iron oxide slag penetration depth is between 0.02 and 0.04 mm;(4)comprehensively considering,the samples with 30% TiN_0.4 heat treated at 1 450 ℃ exhibits superior mechanical properties and thermal stability compared to silicon carbide-corundum composites.

Key words: corundum, TiN_x, slag penetration depth, refractoriness under load, thermal shock resistance

摘要： 为了提高轧钢加热炉用无冷却刚玉基滑轨材料的使用寿命,以白刚玉为主要原料,引入非化学计量比化合物TiN_x(x=0.3、0.4、0.5)作结合剂,利用放电等离子烧结,在1 350、1 400、1 450、1 500、1 550 ℃保温 15 min 热处理制备TiN_x-Al₂O₃材料。研究TiN_x的添加量(体积分数分别为15%、20%、25%、30%、35%)对该材料的相对密度、常温耐压强度、耐磨性、荷重软化温度、抗热震性、与铁的敏感性、抗氧化铁渣侵蚀性的影响,并与 SiC-Al₂O₃ 复合材料作对比。结果表明:1)当热处理温度为1 450 ℃时,随着TiN_x添加量的增加,试样相对密度先增加后趋于稳定;2)当TiN_x添加体积分数为30%时,随着热处理温度的升高,试样的相对密度、常温耐压强度、磨损量均先升高后趋于稳定,荷重软化温度稳定在1 800~1 900 ℃,抗热震性次数大体上呈下降趋势;3)模拟轧钢加热炉的工作环境,即保持1 300 ℃且不密封,试样质量随保温时间的延长先增加后趋于稳定,试样的抗氧化铁渣蚀深度保持在0.02~0.04 mm;4)综合考虑,当TiN_0.4添加体积分数为30%,热处理温度为 1 450 ℃时,试样具有较高的力学性能和热稳定性,优于碳化硅-刚玉复合材料的。

关键词: 刚玉, TiN_x, 渣蚀深度, 荷重软化温度, 抗热震性