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This is just cool. Not practical, just cool!

ACHiPo

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#6
This is just a nifty way to melt metal. I'm sure it takes a lot more energy than it's worth but I just think it's neat.
Inductively heating is a pretty efficient way to heat up ferro-magnetic metal. Hard to tell from the video if that is copper (looks like it at first), if so it must just be radiative? Also wondering what's causing the turbulence--just hot air from the part?
 

Rustrp

Active Member
Active Member
#7
Here's a practical application of induction heating. I occasionally place an order with these folks due to odd sizes or specs. Check out how a bolt is made. They have a few interesting videos on how threads are made, especially the rolled threads. Most of this is just another day in the mill but it's being done at specialty levels. There's a lot of useful technical data on their site.

http://www.portlandbolt.com/

http://www.portlandbolt.com/videos/
 
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rwm

Active User
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#8
If the video color is accurate that should be copper or bronze. The radiant color at the melting point looks to be in the ballpark of 1800-2000 deg. If that were steel it would be blinding white. Great video!
Robert
 

Finster

Active Member
Active Member
#9
Inductively heating is a pretty efficient way to heat up ferro-magnetic metal. Hard to tell from the video if that is copper (looks like it at first), if so it must just be radiative? Also wondering what's causing the turbulence--just hot air from the part?
The "turbulence" is nothing more than it bouncing in a magnetic field. Force (gravity) trying to pull it one way and the field pushing it another.
 

ACHiPo

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#10
The "turbulence" is nothing more than it bouncing in a magnetic field. Force (gravity) trying to pull it one way and the field pushing it another.
That's what made me think it might be ferromagnetic rather than copper or brass. I wouldn't think copper or brass would be bounced around with a magnetic field. I'd also think that steel would settle down after the temp exceeded the Curie point, so maybe it's just convection currents?
 

4gsr

Global Moderator
Staff member
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#11
If the video color is accurate that should be copper or bronze. The radiant color at the melting point looks to be in the ballpark of 1800-2000 deg. If that were steel it would be blinding white. Great video!
Robert
Induction heating will not heat up copper or brass by itself. But when combined with steel, like induction brazing, the steel will melt the copper or brass and make it flow creating a perfect brazed joint.

I've seen this induction process used to heat up big chunks of steel, say 8' diameter solid by up to 18" long to near its melting point. Material is then transferred up into a upsetter and smashed into a shape. To heat up a large solid chunk of iron, it uses a low cycle of eddy current at several thousands of amps pushed through the copper coils. The coils are hollow and chilled water is passed thru to keep the coils from totally melting into a blob of molted metal on the floor. One induction coil or I should say a series of coils require about enough power to light up a small neighborhood! Kid you not!

On the smaller scale, I've used it for surface hardening or case hardening of steel and cast iron. Generally leaves a case depth of about .035-.045" deep and a hardness of 55-62 HRC. The coils run on a high frequency of around 25-35,000 cycles and lots of amps of power.
 

rwm

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#12
Copper or bronze will have induced currents in the material that will oppose the field. That causes the motion.
Check out this video showing the current induced in copper pipe by a magnet. Better yet try it, it's like magic!


Robert
 

pdentrem

Active User
Active Member
#13
We use induction on many metals and their alloys i.e. PB, SN, AG, AU, PD, IN, GE, CU, SB. It is really something to watch a crucible of room temperature metal go to red hot and higher in a very short period of time. It amazes people who are not familiar with induction heating, as there appears to be no source of heat.
Pierre
 

rwm

Active User
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#14
Copper and aluminum can be heated by induction. It is just much harder, typically uses a higher frequency and is not as efficient. That piece sure did not look like steel but I could be wrong.
Here is aluminum:


Robert
 

ACHiPo

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#15
Copper and aluminum can be heated by induction. It is just much harder, typically uses a higher frequency and is not as efficient. That piece sure did not look like steel but I could be wrong.
Here is aluminum:


Robert
Sure enough! Well I'll be!
 

merkelerk

Active Member
Active Member
#16
Copper or bronze will have induced currents in the material that will oppose the field. That causes the motion.
Check out this video showing the current induced in copper pipe by a magnet. Better yet try it, it's like magic!


Robert
I have done this with pipe but also with a thick aluminum plate (1" thick) tilted at a steep angle (80 degrees). The magnet slides down the aluminum "ramp" but very slowly.
 

benmychree

John York
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#18
At Kaiser Steel Corp. Napa Ca. plant (Long gone) they had an induction heater to braze carbide tips onto 1" square steel shanks that were used to face off and bevel the large diameter pipe that was made there (up to 48" diameter and 1" wall thickness). The foundry that I've dealt with since back in the 1960s (Ridge Foundry in San Leandro Ca.) uses an induction furnace to melt their iron; it is BIG and the only thing in the place that one needs to keep away from!
 

Catcam

Steel
Registered Member
#19
That's what made me think it might be ferromagnetic rather than copper or brass. I wouldn't think copper or brass would be bounced around with a magnetic field. I'd also think that steel would settle down after the temp exceeded the Curie point, so maybe it's just convection currents?
the induction coil induces eddy currents in the metal and it is these currents that make it move in a magnetic field of the induction heater. just like the copper coils in an electric motor move.
 

ACHiPo

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#20
the induction coil induces eddy currents in the metal and it is these currents that make it move in a magnetic field of the induction heater. just like the copper coils in an electric motor move.
Makes sense now. Thanks!