When using silicon molybdenum rods, the following main points should be noted:
Furnace drying: Newly built or long-term unused furnaces must be dried before use, with a drying temperature generally between 100-200 ° C. Large furnaces require a longer drying time and ventilation should be taken into account.
Starting voltage: When the silicon molybdenum rod is first used, the resistance will increase sharply with the temperature. The starting current should be 25% -30% of the normal operating voltage, not exceeding 300A. After 15 minutes, use the normal operating voltage. 34
Check fixtures and wires: During use, it is necessary to regularly check whether the fixtures are clamped and whether the wires are loose to prevent component damage or other safety hazards.
Avoid frequent start-up and cooling: The continuous service life of silicon molybdenum rods is longer than the intermittent service life. Repeated heating and cooling of the electric furnace will cause frequent expansion and contraction of the silicon molybdenum rods, and some of the silicon dioxide protective film will fall off. It should not be used frequently below 800 ℃.
Regeneration of protective film: After use in a hydrogen atmosphere, the silicon dioxide protective film on the surface of the silicon molybdenum rod should be regenerated by heating at 1500 ℃ for one hour.
Avoid low-temperature oxidation: Silicon molybdenum rods should not be used for a long time in the temperature range of 400-700 ℃, as they are prone to low-temperature oxidation and damage within this temperature range.
The distance between the electric heating element and the furnace wall: The electric heating element should maintain a distance of 25-30mm from the furnace bottom brick and furnace wall to prevent overheating.
Atmosphere of use: Silicon molybdenum rods are suitable for oxidizing atmospheres, with an upper limit of 1650 ℃. They should not exceed 1350 ℃ when used in reducing atmospheres because the protective layer is easily damaged.
In special circumstances, if a silicon molybdenum rod needs to be used in a hydrogen atmosphere, it should be heated at 1500 ℃ for one hour after use to regenerate the silicon dioxide protective film on the surface of the silicon molybdenum rod. In addition, silicon molybdenum rods are brittle at high temperatures and should not be moved around the electric furnace.
