How many ways to use carburant?

Use method of carburant:

Inside furnace input method

Carburant is suitable for induction furnace smelting, but the specific use varies according to process requirements. Further understanding of graphite carburant for electric furnace steelmaking.

(1) Carburant is used in medium frequency electric furnace smelting, which can be added into the lower part of the electric furnace with materials according to the ratio or carbon equivalent requirements, and the recovery rate can reach more than 95%;

(2) If the carbon content of molten iron is not enough to adjust the carbon content, clean the slag in the furnace first, and then add the carburant. Carbon is dissolved and absorbed by heating molten iron, electromagnetic stirring or manual stirring. The recovery rate can reach about 90. If the low-temperature carburetion process is adopted, that is, only a part of the furnace charge is melted, and all the carburants are added to the molten iron at a time when the temperature of molten iron is low, At the same time, it is pressed into the molten iron with solid furnace charge, to prevent its exposure to the surface of molten iron. This method can increase the carbon content of molten iron by more than 1.0%.

The correct use method of carburant in induction furnace:

1. If the electric furnace above 5T is used, the raw materials are single and stable. We recommend the scattered addition method. According to the requirements of carbon content, add the carburant and metal furnace charge into the lower part of the electric furnace with each batch of materials according to the proportion of ingredients. One layer of metal furnace charge and one layer of carburant can absorb 90% - 95% of carbon. Do not slag the carburant when melting, otherwise it is easy to be wrapped by waste residue, affecting the absorption of carbon;

2. With 3T medium frequency induction furnace, the raw materials are single and stable. We recommend the centralized addition method. When molten iron is first melted in the furnace or a small amount of molten iron is left, the carburant to be added shall be added to the surface of molten iron at one time, and the metal furnace charge shall be added immediately. The carburant shall be fully pressed into the molten iron, so that the carburant can fully contact the molten iron, and the absorption rate is above 90%;

3. If small medium frequency electric furnace is used and the raw materials are mixed with high carbon materials (such as pig iron), we recommend fine adjustment of carburant. After molten steel/molten iron, adjust the carbon content, which can be added to the surface of steel/molten iron. The product can be dissolved and absorbed by eddy current stirring or manual stirring of molten steel (iron) during electric furnace melting. The carbon absorption rate is about 93%.

Outside furnace carburization method

1. Graphite powder sprayed inside the ladle

Graphite powder is selected as the carburant, and the blowing amount is 40kg/t, which is expected to increase the carbon content of molten iron from 2% to 3%. With the gradual increase of carbon content in molten iron, the carbon utilization rate decreases. The temperature of molten iron before carburizing is 1600 ℃, and the average temperature after carburizing is 1299 ℃. Generally, nitrogen is used as the carrier for carbon increase by spraying graphite powder, but under industrial production conditions, it is more convenient to use compressed air, and the combustion of oxygen in the compressed air generates CO, the heat of chemical reaction can compensate part of the temperature drop, and the reduction atmosphere of CO is conducive to improving the carbon increase effect.

2. Use carburant during tapping

100-300 mesh graphite powder carburant can be put into the ladle, or flushed in from the tapping tank with the flow. After the discharge of molten iron, it can be sufficiently stirred to dissolve and absorb as much carbon as possible. The carbon recovery rate is about 50%.

Problems that should be paid attention to when using carburant:

If the carburant is added too early, it is easy to attach near the bottom of furnace, and the carburant attached to furnace wall is not easy to dissolve into the molten iron. On the contrary, if added too late, the opportunity for carburization will be lost, resulting in a slow melting and heating time. This not only delays chemical composition analysis and adjustment time, but also may cause harm due to excessive temperature rise. Therefore, in the process of adding metal charge, it is best to add the carburant bit by bit.

If the amount of carbon added at one time is too large, it can be considered to combine the overheating operation of molten iron used in the induction furnace to ensure that the absorption time of carbon additives in molten iron is 10 minutes. On the one hand, the carbon additives can be fully diffused and absorbed through electromagnetic stirring to ensure the absorption effect; On the other hand, it can reduce the nitrogen content brought by the carburetor.

Do not add them at once, but in batches. After melting, add some. Put a part (about a package) of molten iron into the ladle, and then backwash the carburizing agent in the furnace for 1-2 times, then melt the slag and add alloy.

The following aspects need attention:

1. carburant is difficult to absorb (uncalcined);

2. The distribution of carburant ash particles is uneven;

3. Added too late;

4. The adding method is incorrect. The layered adding method is used. When mirror slag is too much, avoid adding molten iron;

5. Try not to use too much rusty material.

Characteristics of high-quality carburant:

1. The particle size is moderate, the porosity is large, and the absorption rate is fast.

2. The chemical composition is pure, high carbon, low sulfur and harmful ingredients are extremely small, and the absorption rate is high.

3. The graphite crystal structure of the product is good, and the nucleation ability of the molten iron is improved. The number of graphite balls in nodular cast iron is increased during inoculation, and the graphite crystal nucleus is increased in molten iron of electric furnace. Refine and even the distribution of fossil ink in castings.

4. Excellent and stable performance. Graphite carburant product information, welcome to consult us.