Notes on the use of high purity corundum furnace tubes
Source: Henan NOBODY Material Technology Co., Ltd Read: 7253 Time: 2018-07-19 05:49:16
Notes on the use of high purity corundum furnace tubes
In order to improve the service life of high purity corundum furnace tube and reduce the loss caused by damage caused by improper use, the following suggestions are put forward for users' reference:
1. The maximum use temperature of high purity corundum furnace tube should not exceed 1700℃, and the long-term use temperature should be below 1650℃.
2. The high temperature area of high purity corundum furnace tube should avoid mixing impurities, especially metal debris and non-metallic mineral raw materials containing K2O, Na2O, CaO, SiO2, etc., otherwise it is easy to form low temperature eutectic substance and damage corundum tube.
3, high purity corundum furnace tube should try to avoid sharp rise and drop temperature, especially try to avoid the corundum tube directly into the high temperature furnace. When cooling, it should be cooled naturally after the temperature drops to 300 degrees, and the rate of rise and fall is controlled to about 5 degrees Celsius. It can not be cooled by air or cooling water indirectly.
4. If the process or equipment allows, corundum tube should be installed vertically as far as possible to reduce high temperature creep deformation. Try to avoid vibration under high temperature or heating. When installing or using, minimize the support of high temperature heating area or contact with other objects.
5. In order to reduce the cracking of high purity corundum furnace tube, local quenching and heating of high purity corundum furnace tube should be avoided, especially the hot corundum tube should be avoided directly on the firebrick or refractory fiber blanket under normal temperature, otherwise it is easy to burst. At the same time, the sintered material with high temperature and large heat storage should not move on the contact wall of the corundum furnace tube. If it needs to move, the temperature gradient should be controlled within 200℃.
6. In the process of use, if protective gas needs to be passed into the furnace tube, please pay attention to not too fast cold air flow, and it is appropriate to keep 10 bubbles at the outlet per minute; At the same time, the intake gas should be controlled to avoid too little intake gas when cooling, resulting in water suction into the furnace tube, causing the furnace tube burst;
7. In order to avoid rupture of high purity corundum furnace tube due to large temperature gradient changes, it is recommended that the tube plug (or reflection screen) in the furnace tube should not overlap with the position of thermal insulation cotton (or thermal insulation support) outside the tube. According to experience, pushing or pulling the tube plug will improve the service life of the corundum tube accordingly.
8. High purity corundum furnace tube is a brittle and rigid material. For different use conditions and process methods, the service life of corundum tube is not the same, which is greatly affected by the use temperature, rising and cooling rate, atmosphere, sintering volatilization and environmental temperature. Hope users can combine their own process characteristics, summed up a set of operating standards most suitable for use conditions.