There are many kinds of raw materials and production processes of carburizing agents, including wood carbon, coal carbon, coke, graphite, etc., among which there are many small types under various classifications. High quality carburizing agent generally refers to the carburizing agent after graphitization. Under high temperature conditions, the arrangement of carbon atoms is in the micro form of graphite, so it is called graphitization.
Graphitization can reduce the content of impurities in the carburizing agent, increase the carbon content of the carburizing agent and reduce the sulfur content. The use of carburizing agent in casting can greatly increase the amount of scrap steel and reduce the amount of pig iron or no pig iron.
For the feeding mode of electric furnace smelting, the carburizing agent shall be put into the furnace together with scrap and other furnace materials, and the small dose can be added on the surface of molten iron. However, it is necessary to avoid feeding into molten iron in large quantities, so as to prevent the situation that the carburizing effect is not obvious and the carbon content of castings is not enough due to excessive oxidation. The addition amount of carburizing agent shall be determined according to the proportion and carbon content of other raw materials.
For different types of cast iron, different types of carburizing agent shall be selected according to needs. The characteristic of carburizing agent itself is to select pure carbon containing graphitized materials to reduce excessive impurities in pig iron. The proper selection of carburizing agent can reduce the production cost of castings.
Now let's introduce the characteristics of good carburizing agent:
(1) Moderate particle size, large porosity and fast absorption rate.
(2) Pure chemical composition, high carbon, low sulfur, less harmful components and high absorption rate.
(3) The graphite crystal structure of the product is good, which improves the nucleation ability of raw molten iron. Increase the number of graphite balls in nodular cast iron during inoculation and increase graphite crystal nucleus in electric furnace molten iron. Fine and uniform distribution of fossil ink in castings.
(4) Good performance and stability.
