What are the effective principles of intermediate frequency induction furnace heating?
A medium frequency induction furnace is a metal induction heating equipment, which is widely used in metal thermal processing in various industries, such as heating before forging, casting heating, metal quenching and tempering heating, hot stamping heating, hot extrusion heating, etc.
In the medium frequency induction furnace,
the metal workpiece is put into the inductor coil of the medium frequency
induction furnace and the frequency conversion current is generated through
the medium frequency induction power cabinet and sent to the induction coil.
This frequency conversion current with a certain frequency flows in the spiral
copper tube of the induction coil, Produce alternating magnetic field.
According to the right-hand rule of middle school physics, induced currents
(eddy currents) with the same frequency and opposite directions will be
generated inside the metal workpiece. According to Joule Lenz's law due to the flow of eddy currents, a certain amount of heat will be generated by
the metal workpiece. This heat value has a square relationship with current and
a linear relationship with time. This heat causes the metal workpiece to heat
itself. This is the basic principle of medium frequency induction furnace
heating
Four effects that affect the heating of medium
frequency induction furnace
1. The first is the surface effect of the medium
frequency induction furnace heating, which refers to the magnetic field formed
when the alternating current passes through the conductor, and the self-induced
electromotive force is generated on the conductor. It is opposite to the
direction of the applied electromotive force, and the self-induced
electromotive force is the strongest in the center of the cylindrical conductor
and the weakest on the surface. Therefore, the current trends to the surface and
the ferromagnetic parts are placed in the inductor. When the inductor passes
high-frequency alternating current, eddy currents are generated on the surface
of the parts. The strength of the eddy currents is the strongest on the
surface, and the phenomenon is attenuated according to an exponential curve
from the surface to the inside.
2. The proximity effect of the medium
frequency induction furnace heating refers to the current on the conductor due
to the interaction of the current between the adjacent conductors heated by the
medium frequency induction furnace, such as the induction coil and the
induction heating parts, when there is an alternating current passing through.
The phenomenon of redistribution.
3. The ring effect of medium frequency
induction furnace heating means that when the ring-shaped conductor passes high
frequency (or medium frequency) AC current, the magnetic field generated is
concentrated in the ring and dispersed outside the ring, so that the current
passes through the inner surface of the ring conductor At this time, there is a
larger self-induced electromotive force phenomenon outside the ring than the
magnet wire inside the ring.
4. The sharp corner effect of the medium
frequency induction furnace heating refers to the sharp corner of the metal the workpiece and the heating speed through the frequency conversion current will
be faster than the heating speed of other parts.
The heating principle of the medium frequency induction furnace is basically the same as described above. Although there are various forms of heating by the medium frequency induction furnace, the heating principle of the medium frequency induction furnace is similar, and the principle of electromagnetic induction heating is the same as the above description.
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