Use of SiC in the Induction Furnace.(유도로에서 탄화규소의 적용)

USE OF SILICON CARBIDE IN THE INDUCTION FURNACE

 

Pierre-Marie Cabanne, Sorelmetal Technical Services

 

Silicon carbide has only recently been used outside of steel works.

Its appearance in cast iron/Ductile Iron foundry goes back only a few decades. It is not always used advisedly and it could be used more frequently especially complementing Sorelmetal in the charge.

Indeed, one of its principal aspects is its nucleation ability.

In the following we will attempt to show the characteristics and give some advice for using SiC.
The silicon carbide is obtained by electromelting high purity silica sand with petroleum coke, also of good quality.

This “melting” takes place at high temperature (about 4000OF (2200OC)) and requires a large quantity of energy to produce. It also requires energy for it to dissociate into about 2/3 Si and 1/3 C in the induction furnace.

The better quality raw materials produce better quality SiC, which is lower in nitrogen, sulphur, hydrogen and other trace elements.

The Al content also varies according to the final purity of SiC(see table). ......

 

Of all the items already presented, probably the most important is the role of SiC on nucleation and preconditioning of the iron.

As Sorelmetal does, SiC also generates more seeds in the liquid cast iron and improves graphitization!

For the graphitization, Benecke(1) presents the following explanation:

Si and C coming from the dissolution of SiC would be concentrated on a micro level in the liquid iron and would thus give locally an hyper-eutectic character which naturally promotes graphitization.

This of course reduces the chilling tendency and amount of undercooling.

In the same way, during long holding times following stopping of moulding lines or after holding over a weekend, an addition of 2 lb (1 kg)/ton of SiC on the cleaned bath with 15 lb (7 kg)/ton of Sorelmetal, will reduce chill values and make it possible to maintain an acceptable level of graphitization.

 

The ideal charge composition and charging order for a coreless induction furnace would be as follows:

Bottom of furnace:
1) A light raw material cover in small pieces (to protect the bottom of the furnace)
2) Half of the Sorelmetal
3) The steel scrap portion of the charge (40%maximum)
4) 0.5% of SiC plus recarburizing materials, if necessary
5) The returns (maximum 50%)
6) The balance of Sorelmetal
By applying all what has been stated above, your base cast iron will be ready to produce parts that have a lower tendency to form carbides and present a smaller risk to having micro porosity.
For more information you can always contact any of the Sorelmetal Technical Services staff.

 

(1) T. Benecke : “ Solubilité et effet pré-inoculateur du SiC dans les bains de fonte “ – FFA no81 janvier 1989

 

원문관련자료 - 21세기야금연구소

 

논문-0604-Use of SiC in the Indudtion furnace-099_(2006).pdf

 

 

논문-0604-Use of SiC in the Indudtion furnace-099_(2006).pdf

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