Abstract:

To improve the sintering quality of Al₂O₃-C tubes for continuous temperature sensors of molten steel,firstly,the temperatures in different positions in the furnace during sintering were measured,and the variations of the temperature field were analyzed;then,the thermal stress model of the Al₂O₃-C tube head during sintering was established;according to the calculated thermal stress nephogram and the stress,the temperature,the strain curve corresponding to the maximum thermal stress position,the most vulnerably damaged positions were determined and the damage reasons were analyzed;finally,the firing schedule was optimized based on the analysis of the damage reasons and then applied in on site production.The results show that: the actual furnace temperatures in not consistent with the set temperatures;the upper temperatures are higher than the lower temperatures,and the temperatures below the exhaust ports are higher than those at other parts;the three maximum stress positions predicted by the stress model are consistent with the damage positions in the actual sintering;the heating rate in the range of 300-600 ℃ is reduced from 3.3 ℃·min^-1 to 2 ℃·min^-1,which decreases the failure rate from 8/1 000 to 1/10 000.

Key words: determination of temperature field, alumina-carbon tube, sintering process, thermal stress

摘要：

为了提高钢水连续测温传感器Al₂O₃-C管的烧制质量,首先对烧制过程中炉内温度场进行测量,分析炉内温度场的变化规律;然后建立烧制过程中Al₂O₃-C管头部的热应力模型,根据热应力云图和最大热应力位置的应力、温度、应变曲线,确定最易发生损坏的位置,并分析其发生损坏的原因;最后根据分析得到的损坏发生的原因改进烧制过程的温度制度,并用于实际生产。研究表明:炉内的实际温度与设定温度不一致,上部温度高于下部的,排气口下方的温度高于其他位置的;根据应力模型确定的3个应力最大位置与实际烧制过程中的损坏位置一致;将300~600 ℃的升温速率由3.3 ℃·min^-1降低至2 ℃·min^-1后,烧制损坏率由改进前的千分之八减小到万分之一。

关键词: 温度场测量, Al₂O₃-C管, 烧制过程, 热应力