Foundry crucibles

Foundry crucible's Introduce:

Silicon carbide crucibles and graphite crucibles are commonly used high temperature resistant vessels in industrial metal smelting and casting. Compared with graphite crucibles, silicon carbide crucibles are larger and have a longer life. In this article we will explore the advantages of silicon carbide crucibles and the importance of the preheating process.

Advantages of silicon carbide crucible:
1. Thermal conductivity: Using high thermal conductivity materials with dense structure and low porosity, the heat conduction speed is fast.
2. Long service life: Compared with ordinary clay graphite crucibles of the same material, the service life is extended by 2-5 times.
3. High density: Advanced isostatic pressing technology is used to ensure that the material density is uniform and defect-free.
4. High strength: using high-pressure molding, excellent high-temperature strength, high-pressure resistance, and scientific product shaping.
5. Corrosion resistance: Advanced material formula effectively resists the physical and chemical effects of molten substances.
6. Low slag adhesion: The minimal amount of slag adhesion on the inner wall significantly reduces heat resistance and the possibility of crucible expansion.
7. High temperature resistance: suitable for use in the temperature range of 400-1700℃.
8. Low pollution: The material design takes into account the relationship and process characteristics of smelting metals to minimize or eliminate harmful impurities.
9. Metal anti-corrosion: Contains special elements to effectively inhibit metal oxidation.
10. Energy saving and environmental protection: Fast heat conduction can save a lot of fuel and reduce waste pollution. Induction heating can significantly reduce reactive power loss.
11. High oxidation resistance: Advanced antioxidant mechanism provides excellent protection for the graphite in the crucible.

Preheating process:
Many people do not preheat new silicon carbide crucibles, which can easily cause the crucible to break. Therefore, the crucible must be preheated before use. The preheating process includes drying the crucible. The new crucible can be placed near the oil furnace for 4-5 hours before use. Additionally, the charcoal can be burned in the crucible for approximately 4 hours to dry it out. The preheating time and temperature changes of the new crucible are as follows:
- 0℃-200℃: oil slow heating for 4 hours, electric slow heating for 1 hour
- 200℃-300℃: energize and heat slowly for 4 hours
- 300℃-800℃: slow heating for 4 hours
- 300℃-400℃: heat slowly for 4 hours, then heat quickly and keep at 400℃ for 2 hours
After the furnace is shut down, the preheating time for restarting the furnace is as follows:
- 0℃-300℃: slow heating for 1 hour
- 300℃-600℃: slow heating for 4 hours
- 600℃ and above: rapid heating to a certain level.

in conclusion:
When using silicon carbide crucibles, it is critical to follow operating procedures to maximize their value and economics. Preheating the crucible is an important step in the metal smelting and casting process to ensure its durability and performance.