Factors affecting the absorption rate of carbon enhancers

The author of carburizer is highly efficient in the casting industry. In the process of electric furnace smelting, it can reduce the use of cast iron and effectively lower the production cost of castings by adding carburizers to scrap steel furnace materials. However, when using carburizers, there are five factors that affect the absorption rate, and carburizers must be kept in mind by casting personnel!
Yichen Carbon Additive Manufacturer
1. The influence of carbon additive particle size. The carbonization process using carburizer includes dissolution diffusion process and oxidation loss process. The dissolution diffusion rate and oxidation loss rate of carburizers vary depending on their size. The absorption rate of carburizer depends on the combined effect of its dissolution and diffusion rate and oxidation loss rate: in general, carburizer particles are small, dissolution rate is fast, and loss rate is high; The carbon additive has a large particle size, slow dissolution rate, and low loss rate. The selection of carbon additive size is related to the diameter and capacity of the heating furnace. Generally speaking, the diameter and capacity of the heating furnace, as well as the size of the carbon additive, should be larger; On the contrary, the size of the carbonization agent will be smaller. The grain size of crystalline graphite melted in an electric furnace below 1 ton is 0.5-2.5 mm. The grain size of crystalline graphite melted in 1T~3T electric furnaces is 2.5~5mm. The grain size of crystalline graphite melted in 3T-10T electric furnaces is 5.0-20mm. The grain size of the coated crystalline graphite is 0.5-1mm.
Carbonizer manufacturer
2. The influence of the amount of carbon additive added. At a certain temperature and the same chemical composition, the saturation concentration of carbon in an iron solution is constant. Limiting the dissolution of carbon in cast iron (% [C]=1.3+0.0257 T-0.31% (Si) 0.33 [P]% 0.45+0.028 (% S) (Mn%)) at a certain degree of saturation of the iron temperature (T), the more carburizer is added, the longer the time required for dissolution and diffusion, the greater the corresponding loss, and the lower the absorption rate.
3. The effect of temperature on the absorption rate of carburizer. From the perspective of kinetics and thermodynamics, the oxidation of iron solution is related to the equilibrium temperature of C-Si-O system, that is, O in iron solution will react with C and Si. The equilibrium temperature varies with changes in the target carbon and silicon content. When the iron solution is above the equilibrium temperature, carbon preferentially oxidizes, and C and O generate CO and CO2. Therefore, the carbon oxidation loss in the iron solution increases. Therefore, when the equilibrium temperature is higher than the equilibrium temperature, the absorption rate of the carbon enhancer decreases. When the carbon increment temperature is lower than the equilibrium temperature, the saturation solubility of carbon decreases, and the dissolution and diffusion rate of carbon decreases, resulting in a decrease in yield. At equilibrium temperature, the absorption rate of carburizer is high.
4. The effect of stirring of molten iron on the absorption rate of carburizer. Stirring is beneficial for the dissolution and diffusion of carbon, avoiding the carbonization agent from floating on the iron surface due to combustion. Long stirring time and high absorption rate before complete dissolution of the carbon additive. Stirring can also reduce carbonization and insulation time, shorten production cycles, and avoid burning of alloy elements in iron solutions. However, excessive stirring time not only has a significant impact on the service life of the furnace, but also increases the loss of carbon in the iron solution when stirring in solutions with carbonization agents. Therefore, the appropriate stirring time for the iron solution should ensure the complete dissolution of the carbonization agent.5. The influence of chemical composition of molten iron on the absorption rate of carburizer. When the initial carbon content of the iron solution is high, under a certain dissolution limit, the absorption rate of the carbon enhancer is slow, the absorption amount is small, the combustion loss is large, and the absorption rate of the carbon enhancer is low. When the initial carbon content of molten iron is low, the situation is exactly the opposite. In addition, silicon and sulfur in the iron solution can hinder the absorption of carbon and reduce the absorption rate of the carbon enhancer. Manganese helps with carbon absorption and increases the absorption rate of carbon enhancers. In terms of the degree of influence, silicon has a greater impact, followed by manganese, while carbon and sulfur have a smaller impact. Therefore, in the actual production process, manganese should be added first, followed by carbon and then silicon.