In the smelting process, due to improper proportioning or charging, excessive decarburization and other reasons, sometimes the carbon content in the steel can not meet the requirements of the top period, so it is necessary to add carbon to the molten steel. There are many materials that can be used as carburizers for cast iron, such as artificial graphite, calcined petroleum coke, natural graphite, coke, anthracite and mixtures made of these materials.
Attention must be paid to the following aspects in the use of carburizing agent for casting, otherwise its absorptivity will be affected.
1.Effect of particle size of carburizer: the process of carburizer includes dissolution diffusion process and oxidation loss process. The dissolution diffusion rate and oxidation loss rate of different particle sizes of carburizers are different.
2.Effect of carburizing agent for casting: under certain temperature and same chemical composition, the saturated concentration of carbon in molten iron is certain. At a certain saturation, the more the carburizer is added, the longer the dissolution diffusion time is, the greater the corresponding loss is, and the lower the absorption rate is.
3.Effect of temperature on the absorptivity of carburizing agent for casting: when the equilibrium temperature is higher, the absorptivity of carburizing agent decreases; when the carburizing temperature is lower than the equilibrium temperature, the saturated solubility of carbon decreases, the dissolution and diffusion rate of carbon decreases, so the yield is also low. When the carburizing temperature is at the equilibrium temperature, the absorption rate of carburizing agent is the highest.
4.The effect of stirring hot metal on the absorption rate of carburizer: the appropriate stirring time of hot metal should ensure the complete dissolution of carburizer.
These factors are the most important factors affecting the use effect and absorption rate of carburetor
