When the service temperature of high temperature resistance silicon carbide rod is above 600 ℃ or above 800 ℃, the resistance is less affected. When testing the resistance of silicon carbide rod, it is best to measure the resistance at 1000. At this time, the resistivity of silicon carbide rod is 0.10 ohm · cm, but the resistance value has a large range due to the influence of adding process. When floating, the surface load density of berthing surface 3 must be burned. 00 surface negative density refers to the electrical power borne by the surface of the heating part of the silicon carbide rod per unit area, expressed in w / cm. Under the same furnace temperature, if the surface load density is large, the silicon carbide rod can be used less, but the service life of temperature regulation fan Tianrong is short. On the contrary, more silicon carbide rods are used, the service life is long, and the temperature adjustment range is large. Therefore, the surface load honey of silicon carbide rods is inversely proportional to the service life. The power borne by the body surface is related to the structure of dense furnace, furnace temperature, heat transfer mode and atmosphere in the furnace. Various silicon carbide rods specify the parameters of surface load density at the corresponding furnace temperature. Surface load density of silicon carbide rod