Furnace input method
Carburizing agent is suitable for melting in induction furnace, but the specific use is not the same according to the process requirements.
(1) In the medium frequency furnace melting using carburizing agent, according to the ratio or carbon equivalent requirements with the material added to the lower part of the furnace, the recovery rate can reach more than 95%;
(2) liquid iron melting if the amount of carbon is insufficient to adjust the carbon time, first play the furnace slag, and then add carburizing agent, through the liquid iron heating, electromagnetic stirring or artificial stirring to dissolve carbon absorption, the recovery rate can be about 90, if the low temperature carburizing process, that is, the charge only melts part of the molten iron temperature is low, all the carburizing agent once added to the liquid iron, At the same time, it is pressed into the liquid iron with solid charge to keep it from the surface of the liquid iron. This method can increase the carburization of liquid iron by more than 1.0%.
Proper use of carburizing agent in induction furnace
1, the use of 5T or more electric furnace, the raw material is single and stable, we recommend the dispersive adding method. According to the requirements of carbon content, according to the ratio of ingredients, the carburizing agent and metal charge with each batch of material to join the furnace in the lower part, a layer of metal charge a layer of carburizing agent, carbon absorption rate can reach 90%-95%, carburizing agent in melting do not slag, otherwise easy to be wrapped in waste slag, affecting the absorption of carbon;
2. The medium frequency induction furnace of about 3T is used, and the raw material is single and stable. We recommend the centralized adding method. When a small amount of molten iron is melted or left in the furnace, the carburizing agent is added to the surface of molten iron in one time, and the metal charge is added immediately. The carburizing agent is pressed into the molten iron, so that the carburizing agent is fully in contact with the molten iron, and the absorption rate is more than 90%;
3, the use of small medium frequency electric furnace, raw materials with pig iron and other high carbon substances, we recommend carburizing agent fine-tuning. After steel/molten iron melting, adjust the carbon content, can be added to the surface of steel/molten iron, through the eddy current stirring of steel (iron) water or artificial stirring to dissolve and absorb the product, the carbon absorption rate is about 93%.
Outside furnace carburization method
1. Spray graphite powder inside the bag
Graphite powder as a carburizing agent, blowing into the amount of 40kg/t, can be expected to make the carbon content of liquid iron from 2% to 3%. As the carbon content of liquid iron gradually increased, the utilization rate of carbon decreased. The temperature of liquid iron before carburization was 1600℃, and the average temperature after carburization was 1299℃. Graphite powder carburization, generally using nitrogen as the carrier, but in industrial production conditions, compressed air is more convenient, and the oxygen in the compressed air combustion to produce CO, chemical reaction heat can compensate part of the temperature drop, and CO reduction atmosphere is conducive to improving the carburization effect.
2, the use of iron carburizing agent
100-300 graphite powder carburizing agent can be put into the package, or from the iron outlet trough with the flow into, after the iron out of the liquid fully stirred, as far as possible to dissolve the carbon absorption, carbon recovery rate is about 50%.
In the use of carburizing agent should pay attention to the problem
If the adding time of carburizing agent is too early, it is easy to attach it near the bottom of the furnace, and the carburizing agent attached to the furnace wall is not easy to be fused into the liquid iron. On the contrary, adding time too late, will lose the opportunity to add carbon, resulting in melting, heating time slow. This not only delays the time for chemical composition analysis and adjustment, but also risks the harm caused by excessive warming. Therefore, carburizing agent or in the process of adding metal charge bit by bit to join.
Such as in the case of a large amount of addition, can be combined with the induction furnace when the liquid iron overheating operation combined with consideration, to ensure that the carburizer in liquid iron absorption time of 10Min, on the one hand through the electromagnetic stirring effect of carburizer fully diffusion absorption, to ensure the absorption effect. On the other hand, the amount of nitrogen brought into the carburizer can be reduced.
Do not add once, add in batches, and finally melt a part, put a part of the hot iron (about a pack) into the bag, and then back to the furnace carburizer 1-2 times, and then slag, add alloy.
There are several aspects to pay attention to:
1. Carburizing agent is difficult to absorb (without calcination);
2, carburizing agent ash particle distribution is not uniform;
3. Joining too late;
4. The method of joining is not correct, and layered joining is adopted. Avoid liquid iron mirror and too much slag when added;
5. Try not to use too much rusty material.
The characteristics of high quality carburizing agent
1, the particle size is moderate, the porosity is large, the absorption speed is fast.
2. Pure chemical composition, high carbon, low sulfur, very small harmful components, high absorption rate.
3, the product graphite crystal structure is good, improve the original liquid iron nucleation ability. Increase the number of nodular iron nodules in inoculation, and increase the graphite nucleus in electric furnace liquid iron. Refine and even the distribution of fossil ink in castings.
4. Excellent performance and stability.
Selection of appropriate carburizing agent helps to reduce smelting production costs, improve the quality of smelting metal and castings, so that smelting plant, casting
Post time: Dec-02-2022