Abstract:

The zirconia metering nozzle samples heat-treated at 1 300 ℃,1 410 ℃,and 1 540 ℃ for 5 h were analyzed by XRD and SEM to investigate the phase composition and microstructure for studying the effect of the temperature gradient on the damage mechanism of zirconia metering nozzles.The results show that when the samples heat treated at 1 300 ℃,1 410 ℃,and 1 540 ℃ for 5 h are water quenched,the c-ZrO₂ and m-ZrO₂ contents as well as the grain size change significantly.With the increasing heat treatment temperature,the c-ZrO₂ content increases,the m-ZrO₂ content reduces,and the grain size increases,which means that the temperature gradient during continuous casting of metering nozzles will affect the phase composition and the microstructure.In combination of the steel slag corrosion,the damage of metering nozzles will be accelerated,thereby reducing the performance and the service life.

Key words: temperature gradient, phase composition, microstructure, damage mechanism

摘要：

通过XRD和SEM对1 300、1 410和1 540 ℃保温5 h热处理后氧化锆质定径水口的相组成和显微结构进行表征,研究温度梯度对水口损毁的影响。结果表明:定径水口原样分别在1 300、1 410和1 540 ℃保温5 h后水淬冷却,试样中的c-ZrO₂、m-ZrO₂相含量和晶粒尺寸均发生了显著变化。随着热处理温度的提高,c-ZrO₂相含量增加,m-ZrO₂相含量减少,晶粒尺寸增大,说明连铸过程中定径水口产生的温度梯度会对其相组成和显微结构产生影响,并通过与钢渣侵蚀的协同作用,诱导定径水口损毁加速,从而降低其性能和使用寿命。

关键词: 温度梯度, 相组成, 显微结构, 损毁机制