Induction Heating
Induction Heating
(OP)
Hi, I am a newbie to Induction Heating. My question is this: If I am using a conventional helical Cu Coil as Inductor with Solid Steel cylinder as Work piece, Will the heating be from the core of the steel to the surface or the other way. In other words, will the core temperature of the steel work piece be very high and gradually decreases to the steel surface or VICE VERSA..I am confused in which direction this occurs..Also, instead of Solid work piece, if i use a hollow pipe of reasonable thickness (but same diameter), will the property change?
Please help...
Please help...





RE: Induction Heating
RE: Induction Heating
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RE: Induction Heating
When you start the field cannot penetrate very deeply, once the material reaches the curie temperature the field we reach much deeper and heating will become more uniform.
The surface will always be the hottest, but as soon as you turn off the power it starts cooling quickly.
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Plymouth Tube
RE: Induction Heating
RE: Induction Heating
depth is proportional to square root [resitivity/(magnetic permeability*frequency)].
if the work piece is magnetic steel, permeability >>1, so the skin depth is small, at the same time, the heating is easier since there are additional heating contribution from hysteresis losses of the steel itself. when Tem >= Tc, the extra contribution from the steel disappears, but in the meanwhile the increase in resistivity with temperature makes heating easier. The induction heating is not a static process.
RE: Induction Heating
This is why modern power supplies run at variable frequencies. The freq that give the best coupling and efficiency will change as the part heats. You can't change capacitor on the fly, and even though the inductance of the coil is fixed the inductive loading from the work piece is changing.
At first you have to be careful to not overheat the outer surface. After that it become a balancing issue to use the power most efficiently.
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Plymouth Tube