1. The characteristics of smelting in an intermediate frequency furnace
The intermediate frequency induction electric furnace is suitable for melting various grades of molten iron, meeting various composition and temperature molten iron, and meeting the performance requirements of various molten iron. There is a good adaptability. To
Since it is more convenient to adjust the composition of the intermediate frequency furnace, the requirements of the process on the composition range of the molten iron should be narrower to make the performance of the casting more stable. The specific scope can be divided into multiple "brands" according to the types of castings. Or customize special composition requirements for individual castings. To
Because the power of the intermediate frequency furnace is very large, the temperature raising ability is also very strong, and different temperature ranges can be given to different castings to meet the requirements of the castings. To
2. Principles of hot metal batching for intermediate frequency furnace:
Since it is relatively easy to add alloying elements, try to make the original ingredient composition equal to or slightly lower than the target composition in order to adjust the additional alloy after the first test. To
If a component of the molten iron exceeds the target, a large amount of iron material (scrap, pig iron or reheating material) needs to be added to dilute when making adjustments, which will increase the total amount of molten iron, while causing major changes in other elements, which will bring about a chain reaction. Therefore, both ingredients and adjustments are not beneficial to exceed the upper limit of molten iron composition. Exceeding the target value of molten iron composition, it will be very difficult to adjust. To
3. The principle of molten iron temperature control is: as long as the mechanical properties and pouring temperature can be met, the molten iron temperature should be reduced as much as possible to ensure the life of refractory materials. To
The temperature of the molten iron is maintained at 1550°C±5°C when the molten iron cannot be released from the furnace.
4. If sand is brought into the furnace lining, it will be more harmful to the furnace lining, and at the same time it is likely to cause the possibility of scaffolding. Therefore, the furnace material must be cleaned. To
The recycled materials should be stacked separately according to different grades. The recycled materials should be strictly QT450, and other types of recycled materials are not allowed. Gray iron generally can be any other kind, but the proportion should be paid attention to. To
Alloy cast iron (such as Ao Bei Ductile Iron, QT550) is the most economical to use self-produced ductile iron recharge. Can make the yield of alloying elements higher. To
5. Ingredients
The batching of the intermediate frequency induction electric furnace is calculated by the melter, and the result is input into the computer, and the crane feeder is notified in the form of batching. To
6. Adding materials
The order of feeding is: scrap iron (carburizer)-pig iron-recycle material
7 Melt
7.1 When the charge is added to a height of more than 2/3, the power can be sent for melting, and the charge is added while melting, and the entire charge should be added before the iron is completely melted. To
7.2 It is necessary to observe the melting situation of the charge at any time during melting, and pay attention to whether there is a phenomenon of "building a shed" of the charge at any time.
8. C-increasing agent The content, burning loss and average C-increasing rate of C-increasing agent
To
Note: 1. Add C-increasing agent according to molten iron content or batching results. To
2. The particle size of the generally used C-increasing agent is 1-5 mm, which is not suitable if it is too fine.
3. The C-increasing agent should be added in batches, generally in the amount of 1% per batch. To
4. The absorption rate of C-increasing agent is related to temperature.
5. Stir at high temperature for 10-15 seconds. Stirring C for too long will cause burnout.
6.9 Additional calculation of other adjusted elements:
gt=Gz(Xa-Xb)/Cd(kg)
gt- Increase the amount of C agent or other alloys added (kg)
GZ-Total weight of molten iron in furnace (kg)
Xa- target value of molten iron composition (%)
Xb-Analysis value of molten iron composition in the furnace (%)
C-C increase agent or other alloy content (%)
d- Absorption rate of active ingredients (100% is 1)
The C and SI of the molten iron exceed the target composition, add scrap to reduce the calculation of C and SI
gt=Gz(Xb-Xa)/b
B- the content of the adjusted element in the scrap
Other symbols are the same as above
The empirical data is: add 34kg of steel scrap/t, reduce 0.1% C and reduce 0.05% Si
