Induction Heating to anneal cases
- Thread starter Bullet94
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Verrrrry Interesting. I agree it has potential. You'd probably sacrifice a few cases before you figured out the right power and cycle time. But it looks neat. You could have the case on a ram,like on a press) and just raise it up into the coil, then retract.
For those of you who don't know about induction heating, it works by creating an alternating electric current in the heating coil: "The alternating current in the work coil sets up an electromagnetic field that creates a circulating current in the work piece. This circulating current in the work piece flows against the resistivity of the material and generates heat. It's really that simple."
Read this: http://www.ameritherm.com/aboutinduction.php
See the videos on this page:
http://www.ameritherm.com/videoindex.html
For those of you who don't know about induction heating, it works by creating an alternating electric current in the heating coil: "The alternating current in the work coil sets up an electromagnetic field that creates a circulating current in the work piece. This circulating current in the work piece flows against the resistivity of the material and generates heat. It's really that simple."
Read this: http://www.ameritherm.com/aboutinduction.php
See the videos on this page:
http://www.ameritherm.com/videoindex.html
I e-mailed the company listed above about this and will post the results.
My hobby is target shooting. I reload my cartridges and my question is in regards to the brass cases I reload. When firing and resizing my cartridges the brass becomes work hardened, which some reloaders try to anneal to extend the brass life. The methods used by most reloaders seem crude and involve some guess work. I ran across your site and wonder if induction heating to partially anneal the case neck,bring it back to it's original softness) would be possible? Only the neck and part of the shoulder of the case would need to be annealed. The lower ¾ of the case has to remain as from the factory,not annealed) to remain strong enough to take the pressures involved when shot. Some reloaders set their cases in water to make sure the lower ¾ of the case doesn’t get heated when they try to anneal using a torch. If the induction heating process could be used for case annealing there would probably be a lot of reloaders interested, if the price of the equipment to do this was not prohibitive. Does this sound like something that would work and what would the equipment to do this cost?
If you have any question about the above I'll try to answer it.
Thank You,
My hobby is target shooting. I reload my cartridges and my question is in regards to the brass cases I reload. When firing and resizing my cartridges the brass becomes work hardened, which some reloaders try to anneal to extend the brass life. The methods used by most reloaders seem crude and involve some guess work. I ran across your site and wonder if induction heating to partially anneal the case neck,bring it back to it's original softness) would be possible? Only the neck and part of the shoulder of the case would need to be annealed. The lower ¾ of the case has to remain as from the factory,not annealed) to remain strong enough to take the pressures involved when shot. Some reloaders set their cases in water to make sure the lower ¾ of the case doesn’t get heated when they try to anneal using a torch. If the induction heating process could be used for case annealing there would probably be a lot of reloaders interested, if the price of the equipment to do this was not prohibitive. Does this sound like something that would work and what would the equipment to do this cost?
If you have any question about the above I'll try to answer it.
Thank You,
As has been pointed out, how will you heat only the case necks without heating the case body? Any kind of heat sink will just get baked with everything else? I don't see it working.
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Hi Bullet, looks like we are bumping into each other again. I am also very interested in induction heating and am still searching for appropriate info on the internet.
To answer others questions, the coil that is excited can be almost any shape and size including an open coil that the brass can pass through. Cooling of the coil depends upon the power needed. Most available induction heaters are made for industrial applications so are large, expensive and need running water. The need for water is not an absolute. To heat the neck of a cartridge should take a low power heater and may not need running water. I have seen videos of coils that run intermittently without water cooling. To adjust the heating the frequency, current and time of excitation are controlled.
As far as I have so far found, the positive is control of heat and the negatives are complexity,compared to a propane tank)and cost.
One other point brought up is the potential for biological damage. Some industrial heaters are running at radio frequencies at high currents. Significant EMF can be generated.
To answer others questions, the coil that is excited can be almost any shape and size including an open coil that the brass can pass through. Cooling of the coil depends upon the power needed. Most available induction heaters are made for industrial applications so are large, expensive and need running water. The need for water is not an absolute. To heat the neck of a cartridge should take a low power heater and may not need running water. I have seen videos of coils that run intermittently without water cooling. To adjust the heating the frequency, current and time of excitation are controlled.
As far as I have so far found, the positive is control of heat and the negatives are complexity,compared to a propane tank)and cost.
One other point brought up is the potential for biological damage. Some industrial heaters are running at radio frequencies at high currents. Significant EMF can be generated.
AckleymanII
Gold $$ Contributor
I think that you are making a mountain out of a mole hill with this one.
The regular process of annealing with cases standing in a pan with water in it, with the cases heated with a propane torch is very simple, cheap, and it works giving very consistant results.
People imagine all kinds of problems with the propane torch with the pan of water that just are not there.
One problem that folks do not realize is that brass hardness within a lot# may vary as much as 13% in rockwell hardness due to mixture of the alloy. This inconsistant Rockwell hardness gets blamed in a lot of different areas,other than the real cause) and annealing is one of them.
Your efforts would be much better served in sorting brass by the case wall thickness in the webb for increased accuracy.
The regular process of annealing with cases standing in a pan with water in it, with the cases heated with a propane torch is very simple, cheap, and it works giving very consistant results.
People imagine all kinds of problems with the propane torch with the pan of water that just are not there.
One problem that folks do not realize is that brass hardness within a lot# may vary as much as 13% in rockwell hardness due to mixture of the alloy. This inconsistant Rockwell hardness gets blamed in a lot of different areas,other than the real cause) and annealing is one of them.
Your efforts would be much better served in sorting brass by the case wall thickness in the webb for increased accuracy.
AckleymanII
Gold $$ Contributor
I had an engineering firm Rockwell test cases. The results were so depressing, I can't find the positive in it.
PMC brass made in Korea was much harder and consistant than Rem, Win, and Fed & Weatherby was real soft. OF course, there could only be one Lot# of brass tested, Lot # to lot # could also be a whole can of worms.
It would be very interesting to see an engineer that had unlimited access to Rockwell testing do an extensive test on brass. No doubt that this test would indeed shock us all with the little sampling that I had done.
PMC brass made in Korea was much harder and consistant than Rem, Win, and Fed & Weatherby was real soft. OF course, there could only be one Lot# of brass tested, Lot # to lot # could also be a whole can of worms.
It would be very interesting to see an engineer that had unlimited access to Rockwell testing do an extensive test on brass. No doubt that this test would indeed shock us all with the little sampling that I had done.
"I thought one important part of annealing was to only heat the neck and top of shoulder area, how would you do this with induction? use the pan of water?"
Size and shape of coil determines area being heated. Easy to only heat neck of cartridge. Because heating is so quick and only neck is heated, water would not be necessary.
Size and shape of coil determines area being heated. Easy to only heat neck of cartridge. Because heating is so quick and only neck is heated, water would not be necessary.
To quote Ken Light:
http://www.lasc.us/CartridgeCaseAnnealing.htm
Quote
The critical time and temperature at which the grain
structure reforms into something suitable for case necks is
662 degrees,F) for some 15 minutes. A higher temperature,
say from 750 to 800 degrees, will do the same job in a few
seconds. If brass is allowed to reach temperatures higher
than this,regardless of the time), it will be made
irretrievably and irrevocably too soft. Brass will begin to
glow a faint orange at about 950 degrees,F). Even if the
heating is stopped at a couple of hundred degrees below
this temperature, the damage has been done -- it will be
too soft.
Unquote
Most manual annealing is done with a propane torch and the brass neck is heated for 5 to 15 seconds depending upon the brass and torch. Care is taken to not heat the brass body too much. That is why quite often the brass being annealed is sitting in a pan of water and it is tipped over when the correct temperature is reached as observed by the brass changing color.
http://www.lasc.us/CartridgeCaseAnnealing.htm
Quote
The critical time and temperature at which the grain
structure reforms into something suitable for case necks is
662 degrees,F) for some 15 minutes. A higher temperature,
say from 750 to 800 degrees, will do the same job in a few
seconds. If brass is allowed to reach temperatures higher
than this,regardless of the time), it will be made
irretrievably and irrevocably too soft. Brass will begin to
glow a faint orange at about 950 degrees,F). Even if the
heating is stopped at a couple of hundred degrees below
this temperature, the damage has been done -- it will be
too soft.
Unquote
Most manual annealing is done with a propane torch and the brass neck is heated for 5 to 15 seconds depending upon the brass and torch. Care is taken to not heat the brass body too much. That is why quite often the brass being annealed is sitting in a pan of water and it is tipped over when the correct temperature is reached as observed by the brass changing color.
I have seen hand held units for less than $150 on parts trucks. Snap-On, Mac Tools, Matco, etc...
They show pictures of it being used to heat up nuts/bolts to make them easier to remove.
They show pictures of it being used to heat up nuts/bolts to make them easier to remove.
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