After years of practical experience, our factory summed up the following points:
(1) The length of the cold end of the silicon carbide rod shall be equal to the thickness of the furnace wall plus the length of the cold end extending out of the furnace wall. Generally, the extension length of cold end is 50-150 mm, so as to cool the cold end and connecting fixture.
(2) The inner diameter of the furnace through the silicon carbide rod shall be 1.4-1.6 times of the outer diameter of the cold end. If the furnace hole is too small or the filler in the hole is too tightly plugged, the free expansion of the silicon carbide rod will be hindered and the rod will be broken at high temperature. During installation, the silicon carbide rod should be able to rotate 360 degrees freely.
(3) The distance between the silicon carbide rod and the object to be heated and the furnace wall shall be greater than or equal to 3 times of the diameter of the heating part. The center distance between the silicon carbide rod and the silicon carbide rod shall not be less than 4 times of the diameter of the heating part.
(4) The cold end of the silicon carbide rod is connected with the main circuit by aluminum braid or aluminum foil. Clamp the cold end tightly.
(5) The new furnace or the electric furnace which has not been used for a long time shall be dried before use, and the old rod or other heat source shall be used for drying.
(6) The continuous service life of the silicon carbide rod is long, and the intermittent service life is short.
(7) The reasonable surface load density and temperature should be selected when using the silicon carbide rod. The use temperature shall not be more than 1650 ℃; in the use of harmful gas environment, it is necessary to prevent the chemical reaction between silicon carbide rod and harmful gas.
(8) Prevent the molten metal splashing on the silicon carbide rod, which is easy to break the rod.