What are the precautions for the use of high temperature sintering furnaces?
Oct 18,2024
The mold is generally owned by the user, so the mold material basically selects high-purity graphite, the internal pressure limit is 40MPa, and it is safer below 30MPa. It is recommended to calculate the area of the upper and lower punches of the mold before applying pressure, and then convert it into pressure.
1. The formula is as follows:
Allowable pressure in the system (ton) = up or down stamping area 30MPa
If the blind pressure is not calculated in advance, graphite products such as molds, blocks, heating bodies, and insulation screens may be damaged.
2. Thermocouple is tungsten rhenium type, brittle after use, can not contact. In case of damage, replace it in time.
3. In winter, we should pay attention to the heat preservation of the circulating water of the high temperature sintering furnace. Otherwise, it is easy to break the water pipe.
4. The furnace body should be kept in vacuum after use. The insulation layer in the stove is easy to get damp. If you save the vacuum, the next vacuum will be faster.
5. Because the equipment is complex, there must be equipment use regulations, including professional use, professional responsibility, pre-use training for novices, post-use inspection, operation and use records, etc.
6. High temperature sintering can also be used as a vacuum sintering furnace. When used as a vacuum sintering furnace, please pay attention to placing the heat preservation screen cover on the back cover of the crucible in the furnace, and then cover the small lid in the middle. Otherwise it is easy to burn the electric furnace.
7. Before operation, clean the window glass, clean the inner wall of the furnace, observe the water pressure, observe whether the graphite in the furnace is damaged, whether the instrument is normal after electricity, and test whether the hydraulic system is working normally.
8. In the useful thermocouple heating process, the temperature deviation from the infrared (such as large temperature difference) should be used to observe whether the infrared is aligned.
After the high temperature sintering furnace is used for one year, the instrument should be sent to the measurement department for calibration.
10. During operation, hands should be used to contact the furnace cover, furnace body, furnace bottom, electrode, upper and lower pressure head and other parts to prevent excessive water temperature damage.
The high-temperature sintering furnace adopts graphite heating and circulating operation type, with graphite as the thermal element, which is suitable for sintering metal materials and inorganic non-metallic materials in vacuum or protective atmosphere. Can also be used for the calcination and purification of optical materials:
1. Kiln reducing atmosphere
Different combustion atmospheres will change the price of iron oxide in the clay, and eventually burn up to produce products of various colors. The intrinsic factor of the burning that gives the brick a red shape is ferric oxide. Another factor that can determine the apparent color is the combustion atmosphere at the firing stage. Low temperature ferric oxide is stable brown. If the calcination temperature (such as 1000) is unchanged, the content of ferric oxide is unchanged, and the high temperature ferric oxide will lose its stability at low temperature and improve its activity. At this time, the calcination atmosphere in the kiln is a reducing atmosphere, and the triferric oxide will be restored to form triferric oxide or iron oxide, so that the appearance of the product becomes cyan or cyan.
2. Oxidation atmosphere of kiln
An oxidizing atmosphere contains an excess of oxygen of 2% to 5%. The gaseous medium is considered neutral if the excess air is carried out in the range of 1.5 to 2% not exceeding the theoretical requirement for combustion. In a strongly oxidizing atmosphere, the amount of excess oxygen exceeds 10% of the theoretical requirement.
For products baked under oxidizing atmosphere, the brick pile on the kiln car has uniform color up and down, fresh sound, fine texture, saving internal combustion and small amount of black heart. Therefore, the internal combustion brick to promote positive pressure, with micro static pressure or positive pressure can be.
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