Medium frequency induction furnace molten iron, Ingredients, remelting
1. CHARACTERISTICS OF MEDIUM FREQUENCY FURNACE MELTING
The Medium frequency induction furnace is suitable for melting various brands of molten iron, to meet the composition, temperature of molten iron, to meet the performance requirements of all kinds of molten iron. It’s very adaptable.
Because the composition of intermediate frequency furnace is convenient to adjust, the range of composition of molten iron should be narrower in order to make the properties of castings more stable. The specific range can be divided into a number of “grades” according to the type of casting, or for individual casting specific composition requirements.
Because the power of medium frequency furnace is very high, so the ability to raise temperature is very strong, it can give a different temperature range for different casting to meet the requirement of casting.
2. Mixing principle of HOT METAL IN MEDIUM FREQUENCY FURNACE
Since alloying elements are relatively easy to add, try to make the original ingredient equal to or slightly lower than the target ingredient so as to adjust the added alloy after the first test.
If one component of molten iron exceeds the target, a large amount of iron (scrap and pig iron burden) will be added to dilute the molten iron. Therefore, no matter the ingredients, adjustments are not beneficial beyond the upper limit of the molten iron composition. Exceeding the target value of molten iron composition will be very difficult to adjust.
3. The control principle of hot metal temperature is
As long as it can meet the mechanical properties and pouring temperature, as far as possible to reduce the hot metal temperature out of the furnace, to ensure Refractory life.
The hot metal temperature is kept at1350℃±5℃when it is kept in the furnace.
4. It is harmful to the lining erosion if sand is brought into the recycle charge, and it is easy to cause the possibility of erecting shed at the same time, so the recycle charge must be treated by cleaning sand.
Recycle charge should be piled up according to different grades, recycle charge should be used QT450, other kinds of recycling charge should not be used. Gray iron can be used any other general but should pay attention to the proportion.
Alloy cast iron (such as austempered ductile iron, QT550) produced by the use of its own recovery of ductile iron most economically. The yield of alloy elements can be higher.
If the induction furnace by melting charge burden calculation, and the results into the computer, while in the form of batching gantry feed notice.
6. Feed on
FEEDING SEQUENCE: Scrap Iron (carburant)-pig iron-back to the charge
(1) when the burden is added above 2 / 3 Height, the power can be sent to melting, the side melting can be added to the burden, and the entire burden should be added before the burden is completely melted.
(2) the melting of the furnace charge should be observed at any time during melting, and the phenomenon of “building shed” should be noticed at any time.
8. CARBURIZING AGENT
The content of RECARBURIZER, burning loss, and average recarburizing rate
Note: (1) carburizing agent is added according to the content of molten iron or the result of burden.
(2) generally used carburizing agent particle size in 1-5, too fine, not applicable.
(3) carburant should be added in batches, normally at 1% per batch.
(4) The absorptivity of recarburant is related to the temperature.
(5) at high temperature under 10-15 seconds can be, too long stirring carbon instead of burning.
9. ADDITION OF OTHER ADJUSTED ELEMENTS:
Gt Gz (Xa-Xb) / CD (kg)
Gt-carburizing agent or addition of other alloys (kg)
Gz-total hot metal weight in the furnace (kg)
XA-TARGET VALUE FOR MOLTEN IRON COMPOSITION (%)
Analysis value of the composition of liquid iron in Xb-furnace (%)
Carbon-carburizing agent or other alloy content (%)
The absorptivity of d-active ingredient (100% vs 1)
The carbon and SI content in molten iron exceed the target composition, the carbon is reduced by adding scrap, the GTZ (Xb-Xa) / B is calculated by Si
CONTENT OF ADJUSTED ELEMENTS IN B-SCRAP
Other symbols are the same as above
The empirical data are: Add 34kg of scrap iron / T, reduce 0.1% carbon, reduce 0.05% SI