inductive brass annealing

[abunaitoo]

Anyone tried it????
Saw some cheap, made in china, induction modules on ebay.
Don't know much about these things.
What kind of watts would be needed to do brass????

[dikman]

Induction heating generally requires the part to be heated to have some magnetic qualities, so I can't see how this would work with brass.

[Navy Chief]

It works on brass the Annealing Made Perfect is a high end inductive annealing system. I have seen several DIY setups also, have not looked into it too much as I don’t have the electrical or electronic background to engineer a solution.


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[jmorris]

Induction heating generally requires the part to be heated to have some magnetic qualities, so I can't see how this would work with brass.

If you have ever used a microwave, you have used electromagnetic waves for heat transfer. If you look at it that way you won’t see how it couldn’t work with brass.

http://www.gh-ia.com/induction_heating.html

[Idz]

It induces current to flow in the brass which heats it. Main problem is bases get annealed too, not good!

[jmorris]

It induces current to flow in the brass which heats it. Main problem is bases get annealed too, not good!

Depends on how you do it, if you use a torch, over an entire case you could anneal the whole thing but if you just heat the neck quickly, that’s all you anneal.

I have made work coils for float-zone machines (for silicon crystal growth) that can focus heat in a very tiny area. So small, they wouldn’t be very useful for annealing cases.

A “regular” coil and the case inserted into it to the ideal depth would be the way I would go, if flame annealing wasn’t a better solution for me.

[dikman]

Thanks guys for confirming it will work on brass. All the info I found referred to inducing magnetic currents in the metal to be heated, which is a bit difficult in brass. I know that domestic induction cooktops require stainless pots that have a magnetic content (which is why I couldn't buy one).

Microwaves would certainly heat it but I don't think it would be too practical! The beauty of induction heating is that it can be restricted, fairly simply, to a small space. I think the OP should try it, as I would like to know if that little thingy would indeed work on brass.

[dragon813gt]

Anyone tried it????
Saw some cheap, made in china, induction modules on ebay.
Don't know much about these things.
What kind of watts would be needed to do brass????

Duty cycle will make for slow going w/ the cheap ones. You will need a way to cool everything if you want some semblance of speed. Induction annealing is an area where you still have to pay to play. If you're going at it on the cheap one of the varied vertical flame annealers would be the way to go.

[popper]

'induction' method actually relies on eddy current in the metal which doesn't need to be magnetic. Eddy currents are controlled by 'skin' depth of conduction of the metal. Eddy current and metal resistance cause the heat to be generated. For brass the coil frequency is low. Shaded pole electric motor used the same principal.
Big problem is keeping the coil cool while the brass gets hot. One could look up eddy current non-detructive testing for details.

[dikman]

Found this - http://www.grin.uk.com/wp-content/up...ductotherm.pdf - it has a pretty good (read:not too complicated) description of the basic processes involved. Magnetic induction works on magnetic materials (obviously) but only up to the Curie Point, at which stage it becomes non-magnetic so no further heating. To heat above that Eddy Current heating is used, which also works on non-magnetic materials. Frequency and power decide how deep the heating will go.
Most interesting.

I'm guessing, though, that if it were practical to use it for case annealing then there would be built units, kits or how-to's available. I suspect it's much easier to use propane burners.

[country gent]

I would be willing to bet the annealers in the big presses progressive dies are induction done in some form. But in industry making brass cases the quanity is much more and the Pay back faster than it would be for an individual. We had a small bench top induction heater for installing bearing. In the 80s it was over $800.00.
Induction heating would be a fairly controllable heat source and on a rotating case be very even. With the induction heat cycle it may not need to rotate. Also the oxidation may not occur as well.

[abunaitoo]

That is a great site.
Thank you.
Lots of information to absorb.

[jmorris]

I would be willing to bet the annealers in the big presses progressive dies are induction done in some form. But in industry making brass cases the quanity is much more and the Pay back faster than it would be for an individual.

Around 1:20

[abunaitoo]

I wonder if you could visit a maker and tour the plant.

[jmorris]

Probably not in your State.

Contact the company of interest to you and ask, the worst they can say is no.

[dragon813gt]

I'm guessing, though, that if it were practical to use it for case annealing then there would be built units, kits or how-to's available. I suspect it's much easier to use propane burners.

There is plenty of information available in a Google search. And then there are these:
http://www.fluxeon.com
https://www.ampannealing.com
http://www.ez-anneal.com

This isn't a new process. It seems you haven't researched it at al.

[jmorris]

This isn't a new process.

You can say that again...When is the last time you have seen a dame dressed like this at work, in a manufacturing position no less.

[Walter Laich]

the fluxeon seems to be half price of the others

glad I built my own which is the horizontal saw blade and torch type for a couple of hundred $$

[dragon813gt]

the fluxeon seems to be half price of the others

It doesn't have the duty cycle of the others. As well as a bunch of other features. You can add $100 to the base price for the water cooled coil to bring the cycle rate up a good but.

[yeahbub]

Jmorris, did you use off-the-shelf components to build these units or did you do this from scratch? Where did you go for information on how to build them? Inquiring minds want to know. It would be interesting to learn more about how induction units can be built specific to the annealing process, or smelting, for that matter. Maybe a visit to everyone's university-for-everything (Youtube) might shed some light on it.

I looked into smelting lead with induction heating, which would be much more efficient than conventional heating methods. The only thing I lacked was finding a surplus induction unit small enough for my needs. The garage-sized 500kw industrial outfits were a bit large and pricey for 50-100 lbs of wheel weights I wanted to melt. It would have raised eyebrows at the power company billing office too, among other places. I figure 2-5kw ought to do the job quickly enough. I was warned by an experienced shop supervisor familiar with my intentions that a common error is to turn it on full blast for a bit to get things warmed up. If the unit is powerful enough, he said the metal at the hottest point could be brought to vaporization temperatures very quickly before the rest of it melts, and one could wind up breathing metal vapors - lead, in my case , hence, there are attendant cautions about proper use.

What a babe. There were NEVER any like her in factories I worked in.