Silicon Carbide Heating Element Use Precautions
So what should you pay attention to when using silicon carbide rods?
1. The length of the cold end of the silicon carbon rod should be equal to the thickness of the furnace wall plus the length of the cold end extending out of the furnace wall. Generally, the cold end portion has a length of 50 to 150 mm to cool the cold end portion and the connecting fixture.
2. The inner diameter of the furnace through which the silicon carbon rod is inserted should be 1.4 to 1.6 times the outer diameter of the cold end portion. If the furnace hole is too small or the filler in the hole is too tight, the high temperature will hinder the silicon carbon rod from freely expanding and contracting. Baton. When installed, the silicon carbon 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 should be greater than or equal to 3 times the diameter of the heat generating portion. The center distance between the silicon carbon rod and the silicon carbon rod should be not less than 4 times the diameter of the heat generating portion.
4. The cold end of the silicon carbon rod is connected to the main circuit with aluminum crucible or aluminum foil. The clamp at the cold end must be clamped.
5. The new furnace or the electric furnace not used for a long time should be oven before use, and the old rod or other heat source oven should be used.
6. The silicon carbon rod should be protected from moisture when it is stored. Since the aluminum layer of the cold end portion is easily decomposed and peeled off after being wetted, the contact resistance between the cold end portion and the fixture is increased, and the silicon carbon rod is easily broken after being energized.
7. Silicon carbide rods should be damped before use. Silicon carbon rods with the same or close resistance are connected together.
8. A pressure regulating device is provided for the silicon carbon rod. The initial voltage of the power transmission is half of its normal working voltage, and the voltage is gradually increased after a certain period of time. Thus, the silicon carbon rod does not break due to a sharp temperature rise.
9. The silicon carbon rod has a long service life and a short service life.
10. When using silicon carbide rods, choose a reasonable surface load density and operating temperature. The use temperature should be no more than 1650 ° C; use in harmful gas environment to prevent the silicon carbon rod from chemical reaction with harmful gases.
11. When replacing the silicon carbon rod, the silicon carbon rod should be selected to be close to the resistance of the silicon carbon rod running in the furnace. If necessary, replace the whole silicon carbon rod, which is beneficial to improve the service life of the silicon carbon rod. The silicon carbon rod, if the resistance value is appropriate, can also be used in the middle and later stages of the electric furnace operation.
12, to prevent the silicon carbon rod from splashing molten metal, splashing molten metal is likely to cause broken bars.