How to improve the absorption rate of carburizer?

Jul 24, 2020 / 979 views
How to improve the absorption rate of recarburizer ?

The quality of the carburizer is the key to the smelting of gray iron with more waste steel in the electric furnace.In order to avoid pores and other defects, improve the absorption rate of recarburizer , do the following can achieve twice the result with half the effort.

1. The size of recarburizer affects the absorption rate
The recarburizer process using carburizing agent includes dissolution and diffusion process and oxidation loss process.The dissolution diffusion rate and oxidation loss rate are different with the size of carburizer.The absorption rate of carburizer depends on the comprehensive effect of the dissolution and diffusion rate of carburizer and oxidation loss rate: in general, the carburizer particles are small, dissolution rate is fast, loss rate is large;The carburizer has large particle size, slow dissolution rate and small loss rate.The choice of the size of carburizer is related to the diameter and capacity of furnace.In general, the diameter and capacity of the furnace, the size of the carburizer to be larger;On the contrary, the size of carbonizing agent to be smaller.The grain size of crystal graphite for electric furnace melting below 1t is 0.5 ~ 2.5mm.The grain size of crystal graphite for melting in 1T ~ 3T electric furnace is 2.5-5mm.The grain size of crystal graphite for melting in 3T ~ 10T electric furnace is 5.0 ~ 20mm.The grain size of the crystalline graphite covered in the ladle is 0.5 ~ 1mm.

2. The amount of recarburizer   affects the absorption rate
At a certain temperature and the same chemical composition, the saturation concentration of carbon in iron solution is constant.Limit for 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 %] for molten iron temperature (T).Under a certain degree of saturation, the more carburizer is added, the longer time is required for dissolution and diffusion, the greater the corresponding loss, and the lower the absorption rate.
3. Temperature affects the absorption rate of recarburizer
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 reacts with C and Si.The equilibrium temperature varies with the content of target C and Si. When the iron solution is above the equilibrium temperature, carbon oxidation takes precedence, and C and O generate CO and CO2.Thus, the carbon oxidation loss in the iron solution increases.Therefore, when the equilibrium temperature is above, the absorption rate of carburizer decreases.When the carbon increment temperature is below the equilibrium temperature, the saturated solubility of carbon decreases due to the lower temperature, and the dissolution and diffusion rate of carbon decreases at the same time, so the yield is also lower.At equilibrium temperature, the absorption rate of carburizer is the highest.

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4. Agitation of iron solution affects the absorption rate of recarburizer

Agitation is conducive to the dissolution and diffusion of carbon, avoiding carburizer floating on the surface of iron by burning.The stirring time is long and the absorption rate is high before the carburizer is completely dissolved.Stirring can also reduce the time of carbon increase and heat preservation, shorten the production cycle, and avoid the burning of alloying elements in iron solution.But the stirring time is too long, not only has a great impact on the service life of the furnace, and in the solution of carbonizing agent, stirring will increase the loss of carbon in the iron solution.Therefore, the appropriate stirring time should be to ensure the complete dissolution of the carburizer.

5. Iron liquefaction components affect the absorption rate of recarburizer
When the initial carbon content in iron solution is high, under certain dissolution limit, the absorption rate of carburizer is slow, the absorption amount is small, the burning loss is relatively large, and the absorption rate of carburizer is low.The reverse is true when the initial carbon content of molten iron is low.In addition, silicon and sulfur in iron solution hinder the absorption of carbon and reduce the absorption rate of carburizer.Manganese contributes to carbon absorption and increases the absorption rate of carburizer.In terms of influence degree, silicon is the largest, manganese is the second, carbon and sulfur have little influence.Therefore, in the actual production process, manganese should be increased first, then carbon, then silicon.

It can be seen that the correct choice of carburizer manufacturers and the correct use of recarburize r in the casting process can not only eliminate defects, but also reduce production costs and improve the quality of casting products.

Henan star Metallurgical Materials Co., Ltd. was founded in 2007, is located in Anyang, Henan, convenient transportation, is a professional engaged in the production and sales of recarburizer manufacturers, mainly coal carbonizing agent, graphite carbonizing agent, oil coke carbonizing agent, etc., to meet the needs of most domestic manufacturers.In addition to carburizing agent we also deal in spheroidizing agent, inoculant, ferrosilicon, ferromanganese and other products, price concessions, welcome to consult.

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