1. Artificial graphite: among the carburizers, the best quality is artificial graphite.
Artificial graphite is calcined petroleum coke, added with asphalt as binder, and then added with other auxiliary materials. After high-temperature graphitization at 2500-3000 ℃, the ash content, sulfur content and gas content are greatly reduced. Artificial graphite is expensive, so the general carburizing agent is made by using the cutting particles used in the manufacture of electrodes or by grinding the waste electrodes. In addition, the tail material of negative electrode material is also a good source of carburizing agent. The most important indicator of artificial graphite is that the sulfur content is very low, between 0.01-0.07.
2. Petroleum coke: calcined petroleum coke is a widely used carburizing agent. The raw petroleum coke is calcined at 1200-1350 ℃ to become calcined petroleum coke that can be used as a carburizing agent. The sulfur content of calcined petroleum coke is between 0.02-3%, and the calcined petroleum coke that can be used as a carburizing agent is between 0.02-0.5%.
3. Natural graphite
Natural graphite is divided into flake graphite and microcrystalline graphite. Microcrystalline graphite has high ash content and is generally not used as a carburizing agent for cast iron; Flake graphite is generally medium carbon flake graphite used as carburizing agent.
4. Coke and anthracite
When making iron in cupola, coke is used to increase carbon at the bottom, so the use of carburizing agent in cupola is rare. In the process of electric furnace steelmaking, coke or anthracite is used as a carburizing agent, and anthracite is more commonly used as a carburizing agent. Because of their high ash and volatile content, they are rarely used as carburizing agents in induction furnace melting of cast iron.