Induction furnace
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An induction furnace is an electrical furnace in which the heat is applied by induction heating of metal.[1][2][3] Induction furnace capacities range from less than one kilogram to one hundred tons, and are used to melt
The advantage of the induction furnace is a clean, energy-efficient and well-controlled melting process, compared to most other means of metal melting.
Most modern
Induction furnaces do not require an arc, as in an electric arc furnace, or combustion, as in a blast furnace. As a result, the temperature of the charge (the material entered into the furnace for heating, not to be confused with electric charge) is no higher than required to melt it; this can prevent the loss of valuable alloying elements.[5]
The one major drawback to induction furnace usage in a foundry is the lack of refining capacity: charge materials must be free of oxides and be of a known composition, and some alloying elements may be lost due to oxidation, so they must be re-added to the melt.
Types
In the coreless type,[6] metal is placed in a crucible surrounded by a water-cooled alternating current solenoid coil. A channel-type induction furnace has a loop of molten metal, which forms a single-turn secondary winding through an iron core.[7][8]
Operation
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Induktionstiegelofen_Schnitt.png/220px-Induktionstiegelofen_Schnitt.png)
2 - water-cooled coil
3 - yokes
4 - crucible
An induction furnace consists of a nonconductive crucible holding the charge of metal to be melted, surrounded by a coil of copper wire. A powerful
An advantage of induction heating is that the heat is generated within the furnace's charge itself rather than applied by a burning fuel or other external heat source, which can be important in applications where contamination is an issue.
Operating frequencies range from
A preheated, one-ton furnace melting iron can melt cold charge to tapping readiness within an hour. Power supplies range from 10 kW to 42 MW, with melt sizes of 20 kg to 65 tons of metal respectively.[citation needed]
An operating induction furnace usually emits a hum or whine (due to fluctuating magnetic forces and magnetostriction), the pitch of which can be used by operators to identify whether the furnace is operating correctly or at what power level.[citation needed]
Refractory lining
There is a disposable refractory lining used during casting.
See also
- Electric arc furnace—for another type of electric furnace, used in larger foundries and mini-mill steelmaking operations
References
- ISBN 0080523544.
- ISBN 978-1627080187.
- ISBN 0871704781.
- ^ "Technical basics and applications of induction furnaces".
- ISBN 978-0-471-04741-4page 48
- ^ Robiette, A G (1935). "V: Coreless Induction Furnaces". Electric Melting Practice. Charles Griffin & Co. pp. 153–252.
- ^ Robiette 1935 "Chapter IV: Channel Type or 'Low Frequency' Induction Furnaces", pp. 153–252
- ^ Induction and Dielectric Heating. Electricity and Productivity Series, Nº6. British Electrical Development Association. 1962. pp. 8–9.
- ISBN 978-8125918530.
Further reading
- Brown, John (2000). Foseco Ferrous Foundryman's Handbook (11th ed.). Butterworth-Heinemann. ISBN 978-0750642842.
External links
- "How Induction Furnace Are Making It Hot For The Axis", Popular Science, November 1943. Detailed article on the basics with numerous illustrations