Under normal circumstances, in the smelting process, due to ingredients, improper charging, excessive decarbonization and other reasons, the carbon content of steel does not meet the expected requirements, then it is necessary to add carbon to the liquid steel. There are many kinds of commonly used carburizer, such as carburized pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder. In converter smelting, high carbon steel, the use of petroleum coke containing few impurities as carburizer. The requirement of recarburizer for top blown converter steelmaking is high fixed carbon, low ash, volatile matter, sulfur, phosphorus, nitrogen and other impurities, and dry, clean, moderate particle size.
There are many kinds of raw materials of carburizer, the production process is also different, there are wood carbon, coal carbon, coke, graphite, etc., which are classified under a variety of small types. Carburizing agent generally refers to the carburizing agent after graphitization. Under high temperature conditions, the arrangement of carbon atoms is the microscopic form of graphite, so it is called graphitization. The absorptivity of recarburizer depends on the combination of dissolution diffusion rate and oxidation loss rate of recarburizer. In general, the carburizer particles are small, dissolution speed is fast, loss speed is large; Carburizer particle size, slow dissolution rate, small loss rate. The choice of the size of the carburizer is related to the diameter and capacity of the furnace. In general, the diameter and capacity of the furnace, the size of the carburizer is larger; On the contrary, the particle size of the carburizer is smaller.
Using recarburizer in induction furnace, the need to hit the net first furnace slag, plus carburant, by raising the temperature of molten iron, or artificial electromagnetic stirring to dissolve carbon absorption, recovery rate is around 90%, if the low-temperature carbonization process, the melt furnace charge only part of the molten iron liquid under the condition of low temperature, all recarburizer one-time in liquid iron, At the same time, it is pressed into liquid iron with solid charge so as not to expose the surface of liquid iron.
