In the smelting process of iron and steel products, due to the long smelting time, holding time, overheating time and other factors, the melting loss of carbon element in molten iron increases, resulting in the reduction of carbon content in molten iron, resulting in the carbon content in molten iron can not reach the expected theoretical value.
In order to make up for the carbon content in the steel melting process, the carbon containing substances added are called carburizers.
There are many kinds of raw materials for carburizer, and the production process is also different, including wood carbon, coal carbon, coke, graphite and so on, and there are many small types under various classifications. High quality carburizing agent generally refers to the carburizing agent after graphitization. Under the condition of high temperature, the arrangement of carbon atoms presents the micro morphology of graphite, so it is called graphitization.
Graphitization can reduce the content of impurities, increase the content of carbon and reduce the content of sulfur. When carburizing agent is used in casting, the amount of scrap can be increased greatly, the amount of pig iron can be reduced or pig iron can not be used.
In the charging mode of EAF smelting, the carburizing agent should be put in together with the scrap and other charges, and the small dosage can be added on the surface of hot metal. However, it is necessary to avoid mass feeding into the molten iron to prevent excessive oxidation, resulting in less obvious carburization effect and insufficient carbon content in the casting. The amount of carburizer is determined according to the proportion and carbon content of other raw materials.
Different types of cast iron, according to the need to choose different types of carburizing agent. The characteristics of carburizing agent itself is to select pure graphitized material containing carbon to reduce the excessive impurities in pig iron. Proper selection of carburizing agent can reduce the production cost of castings.