Precautions for the Application of Graphite Rods in High Temperature Furnaces

Graphite rods have good high-temperature strength, and their strength gradually increases with the increase of temperature, which will exceed all oxides and metals, so they are often used in high-temperature furnaces. Next, the graphite electrode factory to talk to you about the graphite rod in the high-temperature furnace application matters needing attention.　　

1. The greater the amount of current applied to the graphite rod, the higher the surface temperature of the graphite rod. It is recommended to use the smallest possible surface load density (power). Please note that the value recorded at the cold end of the graphite rod is the current and voltage at 1000°C in the air, which is inconsistent with practical applications. Under normal conditions, the surface power of graphite rods is obtained from the relationship between the furnace temperature and the surface temperature of the graphite rods. It is recommended to use the surface power (W/cm2) of the value of 1/2-1/3 of the ultimate density of the graphite rods.　　

2. Graphite rods can be connected in parallel as much as possible. If the resistance values of the graphite rods are different, the load of the graphite rods with high resistance will be concentrated when connected in series, which will cause a certain graphite rod resistance to be added rapidly and its life will be shortened.　　

3. After the graphite rod is heated in the air, a dense silicon oxide film is formed on the surface, forming an anti-oxidation maintenance film, which has the effect of extending life. In recent years, various coatings have been developed to avoid cracking of graphite rods and used in furnaces with various gases.　　

4. The temperature distribution characteristics of graphite rods. The reflection specification at the time of the new shipment is that the useful fever length is within Δ60℃. Of course, the temperature distribution will increase with its aging, and eventually reach 200℃. The detailed temperature distribution changes are also different due to differences in the furnace atmosphere and operating conditions.　

5. When continuing to use graphite rods, I hope to add resistance slowly to maintain a long life.　　

6. The life of the graphite rod will be shorter as the operating temperature is higher. Therefore, after the furnace temperature exceeds 1400°C, the oxidation rate will accelerate and the life will be shortened. Please be careful not to make the surface temperature of the graphite rod too high during use.

Graphite is widely used in the electrical industry as electrodes, brushes, carbon rods, carbon tubes, positive electrodes of mercury rectifiers, graphite washers, telephone parts, coatings for television picture tubes, etc. In addition, when electrolyzing magnesium, aluminum, and sodium, the anode of the electrolytic cell also uses graphite rods. The resistance furnace that produces emery also uses graphite rods as the furnace head conductive material.