Carburizers play an important role in carbon replenishment during steelmaking and casting. There are many types of recarburizers: petroleum coke recarburizers, graphite recarburizers, graphitized petroleum coke recarburizers and coal-based recarburizers. Among them, the most common influence on the absorption rate is the coal-based carburant. Under normal circumstances, the absorption rate is about 50%-60%. The best recarburizer is a graphitized petroleum coke recarburizer, generally above C98.5, below S0.05, and below N300PPM, with an absorption rate above 90%. It is the best recarburizer in ductile iron.
For castings, cast iron, cast steel, and castings all have requirements for carbon, so carburizers, as the name implies, increase the carbon content in molten iron. For example, the commonly used furnace materials for smelting include pig iron, scrap steel, and recycled materials. Pig iron has high carbon content, but the purchase price is higher than scrap steel. Therefore, increasing the amount of scrap steel, reducing the amount of pig iron, and adding recarburizers can reduce the cost of castings to a certain extent.
During the smelting process, due to improper ingredients or charging and excessive decarburization, sometimes the carbon content in the steel does not meet the requirements of the peak period. At this time, carbon should be added to the molten steel.
Commonly used recarburizers include recarburizer pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder. When the converter smelts medium and high carbon steel grades, petroleum coke with fewer impurities is used as a recarburizer. Top-blown converter steelmaking recarburizer requires high fixed carbon, low content of ash, volatile matter, sulfur, phosphorus, nitrogen and other impurities, and dry, clean, and moderate particle size.