Induction Furnace
The
principle of induction melting is that a high voltage electrical source
from a primary coil induces a low voltage, high current in the metal or
secondary coil. Induction heating is simply a method of transferring
heat energy.
Principles are:
The principle of induction heating is based on the following two laws:
1. Electromagnetic induction
2. The joule effect
The
high frequency induction furnaces use the heat produced by eddy
currents generated by a high frequency alternating field. The inductor
is usually made of copper in order to limit the electric losses.
Nevertheless, the inductor is in almost all cases internally
water-cooled. The furnace consists of a crucible made of a suitable
refractory material surrounded by a water cooled copper coil. In this
furnace type, the charge is melted by heat generated from an electric
arc. The coil carries the high frequency current of 500 to 2000 Hz.
The
alternating magnetic field produced by the high frequency current
induces powerful eddy currents in the charge resulting in very fast
heating. Various configurations are available, with two or three
electrodes high melting capacity (25 to 50 tons/hr) and they are used
primarily for casting steel.
These currents also
provide certain amount of agitation to the melting charge resulting in
efficient mixing. Molten metal can be poured by tilting the furnace.
Advantages:
· Induction furnace does not need electrodes like electric arc furnace.
· Better control of temperature
· Better control of composition of the melt
Disadvantages:
·
An induction installation usually implies a big investment that must be
considered and compared to alternative heating techniques.
· Induction heating is preferably used for heating relatively simple shapes.
Materials to be casted:
· Steel
· Steel alloys
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