Annealing

[mealiejimmy]

That's interesting about the AMP - you're always a mine of information
The following is speculation on my part, but could it be that all the US cartridge makers are sourcing their brass strip from one US supplier and the Europeans from a different European brass strip supplier and that the exact chemical make up of those brass strips is slightly different?

Cheers

Bruce

 

[MarinePMI]

That's interesting about the AMP - you're always a mine of information
The following is speculation on my part, but could it be that all the US cartridge makers are sourcing their brass strip from one US supplier and the Europeans from a different European brass strip supplier and that the exact chemical make up of those brass strips is slightly different?

Cheers

Bruce

Oh, I'd absolutely bet it has to do with the actual brass composition. I know each company tends to have a "proprietary blend" that they use. Some have slightly higher or lower zinc content, as well as other additive metals/metalloids. IIRC, cartridge ("naval") brass is typically 70% copper, 30% zinc, but a lot of variation exists in the additives, that may take up 1-2% .

I suspect it's also why the color can vary between brands, and have a hunch it might have to do with the amount of germanium that is added (or if at all), as well as the variation of copper to zinc ratio. Since it's a metalloid (germanium), it "floats" or migrates to the surface (as I understand it) and helps prevent some oxidation from occurring, and has a yellow'ish tinge to it. I have nothing to back this up at all; it's just a suspicion of mine. I'm not a metallurgist, so could be completely wrong (and it certainly wouldn't be the first time). Incidentally, it's the same stuff that makes Argentium silver tarnish resistant (vice the older Sterling silver).

Anyways, a long winded ramble to say, "Yes, I agree, there are definitely differing brass compositions between brands." Muir and I had a very long discussion about this, with a Chief Engineer of an ammunition manufacturer, and he was clear that brass compositions vary between all the vendors, largely based on desired ductility and malleability due to their machinery and the design of the case (some brands have thicker case walls or necks (e.g. Lapua) and others have very thin walls and necks (e.g. Remington)). The brass stock that is used, varies in composition, as well as thickness, when drawing the cases. With that many variables (machinery/tooling, brass stock thickness, cartridge case dimensions), it's no surprise that each have their own preferred or "proprietary" recipe of "cartridge brass".

 

[25 Sharps]

With an induction annealer you can control time and power - the resultant temperature is a function of both those inputs
In my DIY induction annealer I run at fixed power and control the time
The correct annealing time is determined by measuring the hardness at the case neck
I normally start with a time which, from experience, will probably be too short and measure the hardness after that short anneal
Presuming the hardness is still too high, I anneal again with the time increased by 0.5 second.
I repeat this procedure of annealing and hardness testing until I get to a time which results in the case being annealed to the same hardness as new brass.
Interestingly, I have found with my annealer that European brass (Lapua, Sako, Norma, PPU, RWS and Geco) all require longer annealing times (8-10 seconds) than US brass (Hornady, Winchester, Federal and Remington) 6-6.5 seconds

Cheers

Bruce

Thanks. How do you test the hardness and what is optimal hardness?

Asking as a buddy is working on an induction annealer and once he perfects it he’s putting one together for me.

 

[mealiejimmy]

I use a Webster W20B hardness tester Hardness Testers | Webster Instrument
The anvil has been belt sanded down so that 20 cal and above cartridges can be tested
I gave a local materials testing company 12 lapua 22-250 cases: 4 new, 4 once fired and 4 multiple times fired and got them to do Vickers micro hardness tests at 4 points around the neck of each of the 12 cases.
This was to establish what sort of hardness differences there were between the 3 groups of cases and to give me values to compare with the hardness values from the Webster hardness tester.
The Webster hardness tester has a scale from 0-20 and is not a direct relationship to Vickers.
However, I was able to establish that new lapua brass has a Webster hardness of 12-13, once fired 14-16 and multiple times fired 17-18
On this basis, I anneal for a time that results in a Webster hardness of close to 12, and not greater than 13.
If your buddy wants, I can hardness test some brass for him
I've already done that for someone

Cheers

Bruce

 

[hybridfiat]

If you have a drill press: Place a container full of water below the chuck. Chuck a case up enough to hold it NO MORE and spin. Play the flame over the neck till it turns a very dull red. Switch off, drop the case into the water and chuck up another.
I use a Kitchen Torch like you use for making the caramelised top on Crème Brûlée.

Another method is to stand the cases in a flat container up to about 12mm below the shoulder.
Heat each one at a time till dull red and tip over.
This ensures that the body and base do not get heated.

 

[User00040]

If you have a drill press: Place a container full of water below the chuck. Chuck a case up enough to hold it NO MORE and spin. Play the flame over the neck till it turns a very dull red. Switch off, drop the case into the water and chuck up another.
I use a Kitchen Torch like you use for making the caramelised top on Crème Brûlée.

Another method is to stand the cases in a flat container up to about 12mm below the shoulder.
Heat each one at a time till dull red and tip over.
This ensures that the body and base do not get heated.

Dull red and you have cooked the case.

Better technique is to hold the case in you fingers, around the case head, and rotate slowly over the very end of the flame or just forward of it.

Case is annealed when you feel a little warmth.

 

[Rutland lad]

Dull red and you have cooked the case.

Better technique is to hold the case in you fingers, around the case head, and rotate slowly over the very end of the flame or just forward of it.

Case is annealed when you feel a little warmth.

That’s my recipe too.
Too hot to hold at base means it’s been in the flame too long.

 

[Selous]

With an induction annealer you can control time and power - the resultant temperature is a function of both those inputs
In my DIY induction annealer I run at fixed power and control the time
The correct annealing time is determined by measuring the hardness at the case neck
I normally start with a time which, from experience, will probably be too short and measure the hardness after that short anneal
Presuming the hardness is still too high, I anneal again with the time increased by 0.5 second.
I repeat this procedure of annealing and hardness testing until I get to a time which results in the case being annealed to the same hardness as new brass.
Interestingly, I have found with my annealer that European brass (Lapua, Sako, Norma, PPU, RWS and Geco) all require longer annealing times (8-10 seconds) than US brass (Hornady, Winchester, Federal and Remington) 6-6.5 seconds

Cheers

Bruce

Probably a daft question but how do you measure hardness of the case neck? Edit … sorry I see you have already answered this in detail !!

 

[Alantoo]

Dull red and you have cooked the case.

But not overcooked it.

Dull red neck means you have annealed it rather than just stress relief annealed it. Perfectly usable.

Constancy and repeatability is key. Providing you heat them all to dull red, then the slightly reduced neck tension will be the same for all rounds, and they will obdurate better.

If you want to regain the OEM hardness you could pass them through a full length sizing die a few times to work harden them, but unnecessary provided your load is developed for the same brass state.

Alan

 

[User00040]

But not overcooked it.

Dull red neck means you have annealed it rather than just stress relief annealed it. Perfectly usable.

Constancy and repeatability is key. Providing you heat them all to dull red, then the slightly reduced neck tension will be the same for all rounds, and they will obdurate better.

If you want to regain the OEM hardness you could pass them through a full length sizing die a few times to work harden them, but unnecessary provided your load is developed for the same brass state.

Alan

A dull red under what lighting conditions?

Better to under than over anneal, if the neck gets hot enough for you to see the metal change colour without the room being pitch black, the case is toast!

Consistency is key and I understand that different cases require different amounts of heat but have found the method I described to be consistent.

 

[Alantoo]

A dull red under what lighting conditions?

Better to under than over anneal, if the neck gets hot enough for you to see the metal change colour without the room being pitch black, the case is toast!

Consistency is key and I understand that different cases require different amounts of heat but have found the method I described to be consistent.

Dull red neck under any light conditions will not toast a case.

Best KISS system for stress relief annealing is to use soap which gives you a constant repeatable 400˚C whatever the lighting condition or position in the flame or power of the torch. It also removes the risk of efficiency creep.

Stress Relief Annealing cartridge brass

I have been exploring the subject of cartridge case annealing...well more accurately it is Stress Relief rather then full Annealing temperatures that most reloaders advocate for cartridge case necks. Full annealing of brass (not cartridge cases) when you are working it in the workshop, is...

www.thestalkingdirectory.co.uk

Annealing cases

Hi All I am about to dip my toe in the water of annealing my .243 cases. So far I have bought a blow lamp. I dont do enough reloading to invest in a dedicated annealing machine so what are the top tips for getting it right. Initial try with a crap case and my fingers didnt go too well really...

www.thestalkingdirectory.co.uk

 

[25 Sharps]

I use a Webster W20B hardness tester Hardness Testers | Webster Instrument
The anvil has been belt sanded down so that 20 cal and above cartridges can be tested
I gave a local materials testing company 12 lapua 22-250 cases: 4 new, 4 once fired and 4 multiple times fired and got them to do Vickers micro hardness tests at 4 points around the neck of each of the 12 cases.
This was to establish what sort of hardness differences there were between the 3 groups of cases and to give me values to compare with the hardness values from the Webster hardness tester.
The Webster hardness tester has a scale from 0-20 and is not a direct relationship to Vickers.
However, I was able to establish that new lapua brass has a Webster hardness of 12-13, once fired 14-16 and multiple times fired 17-18
On this basis, I anneal for a time that results in a Webster hardness of close to 12, and not greater than 13.
If your buddy wants, I can hardness test some brass for him
I've already done that for someone

Cheers

Bruce

Thanks, that would be great, I’ll be in touch once the annealer’s built

 

[Lampwick]

I’ve seen people make annealing machines with these!l (or similar)

Any thoughts?

 

[mealiejimmy]

Plenty - enough to build this

Alternatively you could do something like this


Cheers

Bruce

 

[Utectok]

But not overcooked it.

Dull red neck means you have annealed it rather than just stress relief annealed it. Perfectly usable.

Constancy and repeatability is key. Providing you heat them all to dull red, then the slightly reduced neck tension will be the same for all rounds, and they will obdurate better.

If you want to regain the OEM hardness you could pass them through a full length sizing die a few times to work harden them, but unnecessary provided your load is developed for the same brass state.

Alan

Yeah I’m a only just visible dull red man. The necks are very soft and dropping them dents them but they work very well. Only downside is slightly more trimming as the brass moves a bit. Consistency is key imho and my theory is (from what I remember of metal work college) is once it’s annealed it’s annealed and can’t go anywhere. De stress annealing is way to precise a temp to be consistent on….
Anyway whatever works eh!

 

[mealiejimmy]

This guy is a shooter and a metalurgist and these 2 videos are well worth watching.
I also blatantly copied his induction annealer !!!



Cheers

Bruce

 

[Border]

I have used @Alantoo s soap method which works well for me.

 

[Alantoo]

This guy is a shooter and a metalurgist and these 2 videos are well worth watching.
I also blatantly copied his induction annealer !!!



Cheers

Bruce

He is talking about a full anneal in that video, rather than stress relief annealing.

I understood the advantage of stress relief annealing at 400˚C is that you retain the OEM neck tension, but reduce the likelyhood of neck splits thus extending your case life until the primer pockets become loose.

Full anneal beyond recrystallisation makes it dull red territory and much softer. In order to be consistent you would have to anneal new brass to the same level before load development and first fire.

I thought you were stress relief annealing with your Induction machine to match the OEM neck hardness, or are you doing a full annealing like him?

Alan

 

[Alantoo]

Yeah I’m a only just visible dull red man. The necks are very soft and dropping them dents them but they work very well. Only downside is slightly more trimming as the brass moves a bit. Consistency is key imho and my theory is (from what I remember of metal work college) is once it’s annealed it’s annealed and can’t go anywhere. De stress annealing is way to precise a temp to be consistent on….
Anyway whatever works eh!

It is the relative stable point at 400˚C, whatever the starting hardness state that makes it relatively easy to hit consistently with soap. It is before recrystallisation gets going and after the stresses are removed.

I agree that a full recrystallisation anneal is more straightforward and reduces any risk of over or under heating. I always annealed brass and copper to red in the workshop an did the same for the first few times I annealed cartridge cases. But then read that stress relief annealing was the optimum for OEM neck tension, so went for the 400˚C point.

Alan

 

[geoffw]

Dull red neck under any light conditions will not toast a case.

Best KISS system for stress relief annealing is to use soap which gives you a constant repeatable 400˚C whatever the lighting condition or position in the flame or power of the torch. It also removes the risk of efficiency creep.

Stress Relief Annealing cartridge brass

I have been exploring the subject of cartridge case annealing...well more accurately it is Stress Relief rather then full Annealing temperatures that most reloaders advocate for cartridge case necks. Full annealing of brass (not cartridge cases) when you are working it in the workshop, is...

www.thestalkingdirectory.co.uk

Annealing cases

Hi All I am about to dip my toe in the water of annealing my .243 cases. So far I have bought a blow lamp. I dont do enough reloading to invest in a dedicated annealing machine so what are the top tips for getting it right. Initial try with a crap case and my fingers didnt go too well really...

www.thestalkingdirectory.co.uk

Ah, "efficiency creep". Now there's something I'll never have to worry about.

PS Good answer, for a lawyer