Precautions for using graphite rods in high temperature furnaces

What should be paid attention to when graphite rods are used in high-temperature furnaces? The following is a summary of the details:
1. Protective film
After the graphite rod is heated in the air, a high-density silicon dioxide film will be formed on the surface, which will become an anti-oxidation protective film, so as to achieve the effect of prolonging the service life. As the furnace temperature rises and falls, the protective film on the surface of the rod will crack, which reduces the effect of maintenance and accelerates the resistance of the rod to increase.
1) For new rods, the industrial kiln design scheme and application output power can be considered at a relatively low working voltage;
2) With the change of time, the resistance of the rod gradually increases. In order to better meet the design of the industrial furnace and the output power of the application, we need to increase the operating voltage accordingly.
2. Control temperature
When the temperature of high-purity graphite carbon rod exceeds 1400℃ in the furnace, the air oxidation speed will be accelerated and the service life will be shortened. Therefore, everyone should pay attention to controlling the temperature and not allowing its surface temperature to be too high.
3. Slow down and add a resistor
In order to better maintain its service life, we should slowly add resistors when using graphite rods continuously.
4. Series connection
1) Due to the contradictory resistance value of high-purity graphite carbon rods, the load of graphite rods with high resistors is concentrated when they are connected in series, so that a certain graphite rod resistor will be added rapidly, resulting in a reduction in service life.
2) It is necessary to increase the resistance value of the matching group, that is, the resistance value of the same group of rods is as close as possible. The higher the temperature control, the smaller the error of the specified resistance value should be.
5. The total flow of electricity
The greater the amount of current added to the graphite rod, the higher its surface temperature. I suggest using the smallest surface load density (output power) as possible. Under normal circumstances, the output power of the graphite rod surface is obtained from the relationship between its surface temperature and the temperature in the furnace.
6. Characteristics of temperature distribution
The specific temperature distribution of high-purity graphite carbon rods is also different due to the contradiction between the atmosphere in the furnace and the conditions of use.
For newly produced products, the effective fever range is within Δ60°C, which is considered a pass, and the temperature spread will increase as it ages, and may eventually reach 200°C.