Precautions for using high-purity corundum furnace tubes

In order to improve the service life of high-purity corundum furnace tubes and reduce losses caused by improper use, the following suggestions are proposed for user reference:
1. The maximum operating temperature of high-purity corundum furnace tubes should not exceed 1700 ℃, and the long-term operating temperature should be below 1650 ℃.
2. When using high-purity corundum furnace tubes, impurities should be avoided from entering the high-temperature zone, especially metal debris and non-metallic mineral raw materials containing K2O, Na2O, CaO, SiO2, etc., otherwise it is easy to form low-temperature eutectic substances and cause damage to the corundum tube.
3. When using high-purity corundum furnace tubes, it is advisable to avoid sharp temperature fluctuations, especially by directly inserting the corundum tube into a high-temperature furnace. The temperature shall be reduced to 300 ℃ and then Free cooling. The temperature rise and fall rate shall be controlled to about 5 ℃. Air cooling or cooling water shall not be used for indirect cooling.
4. If the process or equipment allows, the corundum tube should be installed vertically as much as possible to reduce high-temperature creep deformation. Try to avoid vibration under high temperatures or heating conditions. When installing or using, try to minimize the support of high-temperature heating areas or contact with other objects.
5. To reduce the cracking of high-purity corundum furnace tubes, local sudden cooling and heating should be avoided, especially for hot corundum tubes, which should not be directly placed on refractory bricks or refractory fiber blankets at room temperature, otherwise they are prone to cracking. At the same time, it is also necessary to avoid sintering materials with high temperature and large heat storage from moving against the wall inside the corundum furnace tube. If movement is necessary, it is best to control the temperature gradient during movement within 200 ℃.
6. During use, if protective gas needs to be introduced into the furnace tube, please be careful not to have too fast a cold air flow, and it is advisable to maintain 10 bubbles at the outlet every minute; At the same time, the intake volume should be controlled to avoid too little intake during cooling, which can cause water to fall into the furnace tube and cause the furnace tube to burst;
7. To avoid the fracture of high-purity corundum furnace tubes due to large temperature gradient changes, it is recommended that the position of the tube plug (or reflection screen) inside the furnace tube should not overlap with the position of the insulation cotton (or insulation support) outside the tube. Based on usage experience, pushing or pulling the tube plug inward or outward will correspondingly improve the service life of the corundum tube.
8. High purity corundum furnace tubes are brittle and hard materials. For different usage conditions and process methods, the service life of corundum tubes varies, and they are greatly affected by usage temperature, temperature rise and fall rate, atmosphere, volatilization of sintered materials, and environmental temperature. We hope that users can summarize a set of operation specifications that are most suitable for their own process characteristics.

The above content is organized by Superb heater Company, super heater. Mainly professional production: industrial heating elements, temperature measuring elements, production equipment, accessories, and raw materials such as tubular heaters, tubular heaters, belt heaters, ceramic heaters, silicone rubber heaters, thermocouples, etc.

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