If there is liquid in the annealing furnace in the usual test, it needs a process of liquid evaporation (it can be gasified without heating under high vacuum). It can gasify this part of liquid by pulling vacuum for a long time, so as to achieve high vacuum (equal stability), If the target pressure is not reached for a long time, you can directly measure the limit vacuum of horizontal microcrystalline vacuum annealing furnace (not connected to other systems). If it is intact, it is the sealing performance of the system. Attention should be paid to the use of vacuum tube in annealing furnace

1. After the furnace is used for the first time or not for a long time, it should be baked at 120 ℃ for 1 hour, and baked at 300 ℃ for 2 hours to avoid furnace cracking. The furnace temperature should not exceed the rated temperature as far as possible, so as not to damage the heating elements and furnace lining. It is forbidden to directly pour various liquids and dissolved metals into the furnace to keep the furnace clean.

2. After the furnace has been used for a period of time, if the vacuum degree decreases, the temperature resistant silicone rubber ring between the stainless steel flange plates can be replaced, or the stainless steel flange plates can be re installed, or the vacuum system can be replaced and repaired, so as to improve the overall vacuum degree of the system.

3. When the cold furnace is used, because the furnace is cold and needs to absorb a lot of heat, the heating rate of the low temperature section is not easy to be too fast, and the difference of the heating rate of each temperature section is not easy to be too big. When setting the heating rate, the physical and chemical properties of the sintered materials should be fully considered, so as to avoid the phenomenon of spraying and polluting the furnace tube.

4. If a quartz tube is used in the furnace, when the temperature is higher than 1000 ℃, the high temperature part of the quartz tube will appear opaque phenomenon, which is called devitrification (also called crystallization). It is an inherent defect of continuous melting quartz tube, which is a normal phenomenon.

5. Regularly check whether the electrical connection part of the temperature control system is in good contact, and pay special attention to whether the connection points of the heating elements are tight.