Restoration of Cartridge Brass

[Ex E6]

Dropping the CBU-105 here ( Restoration of Cartridge Brass ) ductility isn't annealing and really shouldn't be confused as such . Stress relief a little ,if you get neck and shoulder hot enough . I have an inordinate amount of 1943-54 30 Cal. aka 7.62X63mm cases once fired ,along with 1953-57 7.62X51mm cases . Currently have #25 firings on .30 Cal. M1 cases , loaded .5 gr. below max using IMR 4064 & 4895 topped with 150 ,168 and 173 gr. pills . I currently have #21 firings on 7.62X51mm cases using 150, 168 gr. pills also loaded near max . Both run out of MY Gas guns Garands and M14 ,along with a M1A and AR10 platform builds .

Purpose of Post is Education and perhaps reconsideration of Your process . It is what it is and one can't argue against physics and metallurgy .

It has been My privilege to call George My Friend for over 35 years ,having worked on various projects over the decades in the Aerospace field .

Please Note Dwell time at Temperature in order for ANY Recrystallization to even begin ,let alone achieve it.

https://vacaero.com/information-res...rmation-and-annealing-of-cartridge-brass.html


https://www.researchgate.net/public...ND_MECHANICAL_PROPERTIES_OF_CU-32ZN_BRASS#pf4

 

[spife7980]

 

[ma smith]

Mar 25, 2023

 

[Ex E6]

I have that cats twin Fuzz ,big ole Tom showed up #4 years ago as a youngster and has resided here ever since . Must be tough Winter and critters around here can be deadly .

 

[Haney]

Our resident metallurgist should be along soon .

 

[RegionRat]

Purpose of Post is Education and perhaps reconsideration of Your process . It is what it is and one can't argue against physics and metallurgy .

It has been My privilege to call George My Friend for over 35 years ,having worked on various projects over the decades in the Aerospace field .

Please Note Dwell time at Temperature in order for ANY Recrystallization to even begin ,let alone achieve it.

Thanks for the spirit of trying to educate but I'm not sure what is meant by this.

How are those papers supposed to be used for "reconsideration of our process"? How did you use them?

 

[R_A_W]

These papers deal with the hardness of cold-worked brass and the efficacy of subsequent annealing processes...

Both highlight the importance of proper annealing processes after the manufacture of a new brass cartridge (i.e., from a brass cup).

Neither paper observes, measures, or comments on the hardness of fired brass or the annealing of fired brass. Further, the cold working in the papers is considerable:

...cold worked specimens (15, 30, 40, 50, 60 and 70% cold reductions).

and

The plate was then cold rolled with the level of deformation of 20, 40 and 70 % in multiple passes

Ignoring the differences between cold-working and fire-hardening brass, typical reloading processes don't remotely approach those deformation levels (maybe 15% after multiple firings?).

Unless I misread something, these papers provide little information to hobbyist reloaders.

 

[Bandit320]

“Unless I misread something, these papers provide little information to hobbyist reloaders.”

And the reason you posted these for hobbyist reloaders to read?

 

[Bandit320]

Sorry, I was asking the OP.

 

[OREGUN]

“Unless I misread something, these papers provide little information to hobbyist reloaders.”

And the reason you posted these for hobbyist reloaders to read?

Dude, someone has to drop the CBU-105.

 

[supercorndogs]

 

[R_A_W]

Here is something... not exactly the best source

Microstructure and hardness of cartridge case of all of caliber before and after fired did not show significant differences, indicating that the temperature caused by gunpowder explosion did not reach the recrystallization temperature of the material.

For all the die hard annealers... I anneal with 43.5gr Varget

 

[Tokay444]

Dropping the CBU-105 here ( Restoration of Cartridge Brass ) ductility isn't annealing and really shouldn't be confused as such . Stress relief a little ,if you get neck and shoulder hot enough . I have an inordinate amount of 1943-54 30 Cal. aka 7.62X63mm cases once fired ,along with 1953-57 7.62X51mm cases . Currently have #25 firings on .30 Cal. M1 cases , loaded .5 gr. below max using IMR 4064 & 4895 topped with 150 ,168 and 173 gr. pills . I currently have #21 firings on 7.62X51mm cases using 150, 168 gr. pills also loaded near max . Both run out of MY Gas guns Garands and M14 ,along with a M1A and AR10 platform builds .

Purpose of Post is Education and perhaps reconsideration of Your process . It is what it is and one can't argue against physics and metallurgy .

It has been My privilege to call George My Friend for over 35 years ,having worked on various projects over the decades in the Aerospace field .

Please Note Dwell time at Temperature in order for ANY Recrystallization to even begin ,let alone achieve it.

https://vacaero.com/information-res...rmation-and-annealing-of-cartridge-brass.html


https://www.researchgate.net/public...ND_MECHANICAL_PROPERTIES_OF_CU-32ZN_BRASS#pf4

Yeah, no. I anneal, at 550-575°C, not F, and so does everyone else. Thanks for coming out.
LOL@500°F.

 

[Tokay444]

These papers deal with the hardness of cold-worked brass and the efficacy of subsequent annealing processes...

Both highlight the importance of proper annealing processes after the manufacture of a new brass cartridge (i.e., from a brass cup).

Neither paper observes, measures, or comments on the hardness of fired brass or the annealing of fired brass. Further, the cold working in the papers is considerable:

and

Ignoring the differences between cold-working and fire-hardening brass, typical reloading processes don't remotely approach those deformation levels (maybe 15% after multiple firings?).

Unless I misread something, these papers provide little information to hobbyist reloaders.

Also, unless I missed it, no indication as to the starting thickness of the samples of brass.

 

[R_A_W]

Second paper intro

The Cu-32%Zn alloy was produced by gravity casting in a metal mold with the dimension of 110x110x6mm.

 

[Tokay444]

Right, so miles off of the .011" average neck thickness we anneal. The time values are drastically overrated.

 

[ma smith]

Bondan Sofyan

• University of Indonesia

Imam Basori

• Jakarta State University

what could go wrong?

 

[R_A_W]

I anneal, at 550-575°C, not F, and so does everyone else.

I anneal with 43.5gr Varget

 

[Ex E6]

Reading a third language skill ???

NO cartridge manufacturer including Lapua actually anneals ANY cartridge case !. They simply use a multiple station annealing induction machine ,to induce ductility NOT anneal . Consider Temperature and Dwell TIME . Brass sheet is puck punched , then drawn into case form through a series of draws ( Yes Brass at this stage might be held at temp for ductility purpose but again NOT annealed . Think about it CASE HEAD is nearly fully work hardened by drawing and press forming . The head is where the STRENGTH is needed most and Body somewhat ,Neck and shoulder NO ,not so much it's why the witness rainbow of ductility induction is present . Most Military rounds are Not polished ,only commercial and home reloaders polish . Annealing steel HARDENS it ,annealing BRASS softens it ,as BOTH orientate GRAIN STRUCTURE aka recrystallization .
Decades ago I had George cut #6 New cases of mine and do an analysis on them . NOT a single one showed any annealing in the true sense of the word , using OES and TEM machines . Cartridge brass Alloy of copper and zinc. Commonly contains lead. Also may include iron, manganese, aluminum, silicon and other elements as well . SI aka Silicon imparts Hardness in brass . Benefits better corrosion resistance ,lower conductivity improves strength ,considered High Strength Brass . I don't remember all the details as it was in the 90's but DO remember Laupa had a higher % content of SI ,then other cases he tortured or I sacrificed



Annealing experiments were conducted on a number of the cold worked specimens. Figures 5a and b show color etched images of the specimens cold reduced 50% and then annealed 30 minutes at 500 and 700°F. No difference in the microstructure is seen in the specimen held 30 minutes at 500°F while a very small amount of recrystallization is observed in the specimen held 30 minutes at 700°F. Figures 6a and b show color images of 50% cold reduced specimens held for 4 and 8 minutes at 800°F while Figures 6c and d show 50% cold reduced specimens held 15 and 30 minutes at 800°F. No change is observed after 4 minutes at 800°F, while a minor amount of recrystallization has occurred after 8 minutes. Holding specimens for 15 and 30 minutes at 800°F revealed partial recrystallization after 15 minutes and full recrystallization after 30 minutes. The grain structure is relatively fine but is not uniform in its distribution.


Figures 7a and b illustrate the grain structure in color after 15 and 30 minutes at 900°F. The 15 minute hold produced a non-uniform grain structure while the 60 minute hold produced better results although the grain size distribution appears to be duplex. Figures 8a and b show a B&W and a color image (Klemm’s I reagent) after annealing 30 minutes at 1300°F which produced a fully recrystallized, uniform grain size distribution but coarse grained (as in Figs. 1 and 3a). Figures 8c and d show the same specimen but color tint etched using Klemm’s III and Beraha’s PbS tint etchants. Both are excellent for use with cartridge brass. Tint etchants also reveal details about the presence, or absence, of crystallographic texture. We note that as the cartridge brass is cold reduced greater amounts the grain coloring becomes more monotone, while when the annealing temperature is increased resulting in fully recrystallized grains with increasing size, the coloring becomes more variable with a random distribution of the colors. A random dispersion of a broad range of colors indicates that we have a random crystallographic texture while a narrow color range suggests that we have a preferred texture.

Annealing experiments were conducted on a number of the cold worked specimens. Figures 5a and b show color etched images of the specimens cold reduced 50% and then annealed 30 minutes at 500 and 700°F. No difference in the microstructure is seen in the specimen held 30 minutes at 500°F while a very small amount of recrystallization is observed in the specimen held 30 minutes at 700°F. Figures 6a and b show color images of 50% cold reduced specimens held for 4 and 8 minutes at 800°F while Figures 6c and d show 50% cold reduced specimens held 15 and 30 minutes at 800°F. No change is observed after 4 minutes at 800°F, while a minor amount of recrystallization has occurred after 8 minutes. Holding specimens for 15 and 30 minutes at 800°F revealed partial recrystallization after 15 minutes and full recrystallization after 30 minutes. The grain structure is relatively fine but is not uniform in its distribution.


The entire point of MY posting this was so that YOU ,could determine IF YOU were really doing YOUR brass any real service by pretending too anneal it !?. I impart ductility personally and use Higher heat at a mid Dwell , and FYi The ONLY way I know to RUIN a cartridge case in heating ,is allowing the Mid body or base to ever reach 400 F. Deg. THAT IS RUINING A CASE !. My necks and shoulders see 1100-1300 F. Deg ,yet the bases NEVER exceed 250 F. Deg. and I Don't stand them in water or tip them ,unnecessary IMO does Nothing .

IF one stops and thinks about this ,you will understand a cartridge case CAN'T BE ANNEALED and used for it's intended purpose .
Think of your case as a head gasket ,yep metallic . Neck expands then Seals chamber so gases move forward ,shoulder shifts to retard expansion of body . IF it's hard it's gonna SPLIT or allow carbon blow by .

 

[MK20]

They simply use a multiple station annealing induction machine ,to induce ductility NOT anneal

Apparently English comprehension is a third language skill for you.

 

[Ex E6]

Also, unless I missed it, no indication as to the starting thickness of the samples of brass.

.338 Cartridge case ( Cold Work at Firing Pin of a 338 Caliber Cartridge Case )

 

[Tokay444]

.338 Cartridge case ( Cold Work at Firing Pin of a 338 Caliber Cartridge Case )

Well none of us anneal the “Firing pin area”.
Annealing steel does not harden it.

 

[RegionRat]

Ex E6,
I don't think anyone here means any harm, but sometimes the anonymity of the internet combines with ego and less than good writing, and produces swirl where it doesn't belong.

In the ammunition industry, we do call it annealing when we reduce the hardness of the neck. In fact, there are several annealing steps to making a cartridge case and the terminology was given long before my grandfather was born.

No need to argue over this or die on a hill over the word annealing, and in fact it would be counterproductive.

We call it annealing in the plant, and we call it annealing at home. You started the thread with the intent of education on annealing so lets get back to that....

I will offer up a paper written long ago, that shows the whole premise that annealing in the context of cartridge case manufacturing has been understood for well over 100 years.

If you have a desktop version or more complete version of Adobe's pdf software, you can search on the word "anneal" in the article and see how many places it comes up. This article also covered rimfire cases, so when you have a chance read the whole thing.

https://ia804700.us.archive.org/21/...tion Making-NRA by G. Frost-(1990) _text.pdf

The comments that followed your post, and the path that led the thread into swirl... was the question of what you saw in those papers you site that would be useful for someone who doesn't have the science or production background to know about annealing at home.

In many plants, the flame and induction neck annealing lines are used for multiple calibers. In others, they are dedicated to one case design. It just depends on where you look.

However, they are not news and certainly not waiting for the papers sited above to learn anything new.

Based on the idea that folks reloading and annealing at home has been based on the same ideas used in production facilities for generations, I still don't see how those articles would cause anyone to look at their home process and learn anything they can use. Maybe we should all declare a cease fire and you can point out what the take-away highlights of those papers should be and why you thought they were important enough to post?

 

[Ex E6]

Well none of us anneal the “Firing pin area”.
Annealing steel does not harden it.

A Typo on MY part You are correct it also softens steel or changes it's crystalline structure ,generally in preparation for Reheating and hardening steel . I admit when I make errors .

The Firing pin area was simply for visual lattice aka crystalline structure . The BRASS used in the ENTIRE analysis was .338 Cartridge brass .

MY point was to show cartridge cases are NOT annealed Period ,along with the total misinformation pertaining to various degrees required when " Others " refer to neck and shoulder temperatures as gospel . I went down the road of 750 F. Deg. 850 F. Deg neck temp using tempilac . Worthless what good does that do ?. So after conversing with George and getting and education in metallurgy , I began viewing things differently .
I'm a Chemist ,PhD. in Organic chem polymer disciplines ,formulating various epoxies and specialty coatings for the Aerospace Industry . I also worked for Scaled Composites Inc. as their Materials Processing Engineer for 26 years ,Now Retired .

It seems only logical Higher heat shorter duration ,so as NOT to disrupt Body and base of cartridge structure which is critical . Clearly as it's written HIGHER temps is required to even impart ductility .

Makes NO difference to ME ,whether anyone takes it on face merit or not ,just posted it for everyone's assessment .

Remember back when everyone was Neck sizing only ?. For what purpose ? . I've always FL sized and Never bought into neck sizing only . Yet it's others prerogative to do as they please and they will continue doing what they believe works for them ,as will I .

It's the 21 St. Century ,time for folklore and Myths to give way to Science . All the smoke and mirror fiction is on the Media and big house .

 

[OREGUN]

So what is happening when I heat the neck of my fired cases? It’s not annealing, got it. Not hot enough to impart ductility, got it. So…what’s happening that causes my resizing process to be more predictable and more consistent If I do the heat treatment? I’m genuinely interested. I don’t know shit about metallurgy and apparently I’ve fallen for the smoke and mirrors of “big Annealing” marketing gurus.

 

[supercorndogs]

If it made no difference to you, you wouldn't have come here to post about it. You came here for a reason. You signed up for a reason. Are you going to answer post #23 or what?

Its funny how all these big brain annealing posts don't include targets and brass tracked for multiple firings. Absent that, you probably shouldn't get butt hurt if people who have done it disagree.

Everyone online is an aerospace engineer spacetronaught pilot, it doesn't lend credibility to your online persona.

My take away from case annealing has been that stress relief is what we want and "recrystallization" doesn't matter. But to say it can't recrystallize in a short amount of time would be to say AMP is lying about what their machine can do in a matter of seconds.

 

[918v]

I want to anneal my 9mm brass

 

[Punkur67]

I want to anneal my 9mm brass

 

[FLIGHT762]

O/P started this same thread over on The High Road last Monday. https://www.thehighroad.org/index.php?threads/cartridge-case-ductility-verses-annealing.918429/

On a quest to get the truth out. I don't GAF one way or the other.

So what's the term we all should be using for this cartridge case neck / shoulder ductility process? Maybe have a contest to come up with it?

I don't know how many years it will take the Community to get rid of the "A" word and use a better sounding name for the process than the lame Scientific name?

How about something like case and restoration. "Castoration" I'm going to Casetorate my brass. I'm giving my brass a Casetoration.

 

[straightshooter1]

So what is happening when I heat the neck of my fired cases? It’s not annealing, got it. Not hot enough to impart ductility, got it. So…what’s happening that causes my resizing process to be more predictable and more consistent If I do the heat treatment? I’m genuinely interested. I don’t know shit about metallurgy and apparently I’ve fallen for the smoke and mirrors of “big Annealing” marketing gurus.

By now, you must have read the research that Annealing Made Perfect published on their website . . . ??? Or do you discount as it being nothing more than something produced by "marketing gurus"?

If one focuses on the data presented there, I feel one gets a good idea what's being done when the brass is "annealed".

Induction Annealer | The Latest Research | AMP

View the latest articles from AMP Annealing. Get tips and tricks from our R&D. Here we upload articles to provide your the best possible information on innovations in the annealing process.

www.ampannealing.com

 

[OREGUN]

By now, you must have read the research that Annealing Made Perfect published on their website . . . ??? Or do you discount as it being nothing more than something produced my "marketing gurus"?

If one focuses on the data presented there, I feel one gets a good idea what's being done when the brass is "annealed".

Induction Annealer | The Latest Research | AMP

View the latest articles from AMP Annealing. Get tips and tricks from our R&D. Here we upload articles to provide your the best possible information on innovations in the annealing process.

www.ampannealing.com

Smoke and mirrors bro. Myths and folklore. See post #24.

 

[straightshooter1]

Smoke and mirrors bro. Myths and folklore. See post #24.

Hmmm??? OK. So, you're a cynic.

 

[RegionRat]

I think I may now have a clue where this was all meant to go, but if so, it certainly missed the points the OP was trying to make on the opening of the thread.

Maybe this is what he was trying to say....

That 750 F Tempilaq, and Tempilaq as used for necks in a flame and in general, are vague and also too cold to accomplish the annealing goals of the neck.

The challenges of jumping from thick metallurgical samples as used in academics and in standardized tests, versus going down to the thin sheet dimensions of necks, makes the temperature/time measurement topic more difficult for the home reloader.

Would that have covered it?

That said, I'm still of the opinion that George's web site and the sited paper didn't do this forum any good on those two points, even if I admit Tempilaq and 750 F are not good enough for home annealing if the goal is to get the hardness down near 90. YMMV

 

[supercorndogs]

O/P started this same thread over on The High Road last Monday. https://www.thehighroad.org/index.php?threads/cartridge-case-ductility-verses-annealing.918429/

On a quest to get the truth out. I don't GAF one way or the other.

So what's the term we all should be using for this cartridge case neck / shoulder ductility process? Maybe have a contest to come up with it?

I don't know how many years it will take the Community to get rid of the "A" word and use a better sounding name for the process than the lame Scientific name?

How about something like case and restoration. "Castoration" I'm going to Casetorate my brass. I'm giving my brass a Casetoration.

I think we should use the same terminology as people who make brass cases for bottle neck rifle cartridges and call it "annealing."

I will take that over some online super scientist that sniffs adhesives or what ever.

Drawing Brass | How Cartridge Cases Are Made | Peterson Cartridge

See the brass rifle casing manufacturing process at Peterson Cartridge from raw brass coils to the finished casings we deliver to you.

www.petersoncartridge.com

 

[Baron23]

Does the word “pedantic” strike a familiar note.

 

[Doom]

So what is happening when I heat the neck of my fired cases? It’s not annealing, got it. Not hot enough to impart ductility, got it. So…what’s happening that causes my resizing process to be more predictable and more consistent If I do the heat treatment? I’m genuinely interested. I don’t know shit about metallurgy and apparently I’ve fallen for the smoke and mirrors of “big Annealing” marketing gurus.

This step that we call annealing is actually a stress relieving heat treatment. When metal is deformed/worked to a new shape the process leaves residual stress in the material and makes it susceptible to stress corrosion cracking. IN the case of brass one of the most significant chemicals that cause stress corrosion is ammonia, which is a common environmental chemical in air, as most living creatures emit ammonia in some form. Not to mention fertilizer.

 

[Ex E6]

So what is happening when I heat the neck of my fired cases? It’s not annealing, got it. Not hot enough to impart ductility, got it. So…what’s happening that causes my resizing process to be more predictable and more consistent If I do the heat treatment? I’m genuinely interested. I don’t know shit about metallurgy and apparently I’ve fallen for the smoke and mirrors of “big Annealing” marketing gurus.

NO ; You get some ductility YES , true annealing NO . NO grain reformation or growth ,so technically it's " Solution annealing " .

If one simply stopped and consider the TIME and Temp. required ,it's a NO brainer .

 

[iceng]

These AI-bots are shit. Not sure why they keep trying to post.. but more fun than chyna spam.

 

[Ex E6]

This from a former colleague who shall remain nameless ; His employer has put Billions of people in the Air for decades ,so kinda of figure HE knows what he's talking about .

Oh My Doc ; Another educational series ?

Annealing is a heat treatment process used mostly to increase the ductility and reduce the hardness of a material. This change in hardness and ductility is a result of the reduction of dislocations in the crystal structure of the material being annealed. Annealing is often performed after a material has undergone a hardening or cold working process to prevent it from brittle failure or to make it more formable for subsequent operations.

The annealing process requires the material be brought above its recrystallization temperature for a set amount of time before cooling. The cooling rate depends upon the types of metals being annealed. For example, ferrous metals such as steel are usually left to cool down to room temperature in still air while copper, silver, aluminum and brass can either be slowly cooled in air or quickly quenched in water.
The heating process causes atoms to migrate in the crystal lattice and the number of dislocations reduced, which leads to the change in ductility and hardness. The heat treated material recrystallizes as it cools. The crystal grain size and phase composition depend on the heating and cooling rates and these, in turn, determine the material properties.
Hot or cold working of the pieces of metal following annealing alters the material structure once more, so further heat treatments may be required to attain the desired properties.
However, with knowledge of material composition and phase diagram, heat treating can soften metals and prepare them for further working such as forming, shaping and stamping, as well as preventing brittle failure.
An annealing furnace works by heating a material above the recrystallization temperature and then cooling the material once it has been held at the desired temperature for a suitable length of time. The material recrystallizes as it cools once the heating process has caused atom movement to redistribute and eradicate dislocations in the workpiece.
Annealing works in three stages – the recovery stage, recrystallization stage and the grain growth stage. These work as follows:

Recovery Stage​

This stage is where the furnace or other heating devices are used to raise the temperature of the material to such a point that the internal stresses are relieved. ( Brass cartridge restored ductility ,also known as solution annealing )

Recrystallization Stage​

Heating the material above its recrystallization temperature but below its melting point causes new grains to form without any residual stresses.

Grain Growth Stage​

Cooling the material at a specific rate causes new grains to develop. After which the material will be more workable. Subsequent operations to alter mechanical properties can be carried out following annealing.

​

Annealing is used to reverse the effects of work hardening, which can occur during processes such as bending, cold forming or drawing. If the material becomes too hard it can make working impossible or result in cracking.
By heating the material above the recrystallization temperature, it is made more ductile and therefore ready to be worked once more. Annealing as does solution annealing also removes stresses that can occur . However in the latter process No changes will occur in the lattice ,thereby negating any type of recrystallization or grain growth . Stress relief is all one may obtain .
Metal fabricators use annealing to help create complex parts, keeping the material workable by returning them close to their pre-worked state. The process is important in maintaining ductility and reducing hardness after cold working. In addition, some metals are annealed to increase their electrical conductivity.

​

Annealing can be carried out with alloys, with a partial aka solution annealed or full anneal being the only methods used for non-heat treatable alloys. The exception to this is with the 5000 series alloys, which can be given low temperature stabilization treatments.
Alloys are annealed at temperatures of between 300-410°C ,572 F. - 770 F. , depending on the alloy, with heating times ranging from 0.5 to 3 hours, depending on the size of the workpiece and the type of alloy. Alloys need to be cooled at a maximum rate of 20°C 68 F. per hour until the temperature is reduced to 290°C, 554 F. , after which the cooling rate is not important.

​

The main advantages of annealing are in how the process improves the workability of a material, increasing toughness, reducing hardness and increasing the ductility and machinability of a metal.
The heating and cooling process also reduces the brittleness of ferrous metals while enhancing their magnetic properties and electrical conductivity.

​

The main drawback with annealing is that it can be a time consuming procedure, depending on which materials are being annealed. Materials with high temperature requirements can take a long time to cool sufficiently, especially if they are being left to cool naturally inside an annealing furnace.

I believe I can embrace this clarification of annealing concerning Brass cartridge cases ;
Copper Aluminum Brass and their alloys can be subject to a process called solution annealed ,which isn't true annealing in the definition of the process .

During the actual annealing process, the metal is heated to a specific temperature where recrystallization can occur. At this stage, any defects caused by deformation of the metal are repaired. The metal is held at that temperature for a fixed period, then cooled down to room temperature either on it's own or by alternate means .

Best regards ; CF ; The Works

 

[straightshooter1]

So what is happening when I heat the neck of my fired cases? It’s not annealing, got it. Not hot enough to impart ductility, got it. So…what’s happening that causes my resizing process to be more predictable and more consistent If I do the heat treatment? I’m genuinely interested. I don’t know shit about metallurgy and apparently I’ve fallen for the smoke and mirrors of “big Annealing” marketing gurus.

Don't know if you've got a satisfactory answer to your question in this thread or in another thread. Here's how I can best explain it simply: As Doom said, what's happening when you heat the neck of your fired cases is that it releives stress within the metal. The heat and time of heat work together to grow the grains in the grain structure within the brass. As the grains get larger the brass become more ductile. Work hardening cause the grain structure to shrink and become more brittle. The right amount of heat will make the grains grow, but you don't want them to grow too much to where you get a full anneal. There just needs to be enough to ease the stress in the brass that work hardening has induced.

Relieving this stress (not a full anneal) makes the brass keep its shape when formed within a sizing die (with as little spring back as possible) and still enough strength to perform (as in holding the bullet securely in the neck). The better that brass keeps its shape when formed in a sizing die with little spring back, is where you get your consistency.

Other methods can work to maintain consistency and that has a lot to do with matching sizing dies with chamber dimensions so that there's very little movement (expansion and contraction) of the brass that will work harden it. But if one doesn't have custom chambers and/or dies, then Relief Annealing is what will produce more consistency in sizing results and extend the life of the brass.

 

[iceng]

Stop feeding the bots. They are learning off comments. Ignore and move on.

 

[Tokay444]

This says otherwise
"For instance, in Walker’s landmark study, at 70% cold work and performing annealing to the point of complete recrystallization at temperatures of 350◦C, 400◦C, 550◦C, and 650◦C, the average grain diameter was consistently at 0.015 mm. Moreover, from this 1945 study on cartridge brass, a higher annealing temperature required less time to produce complete recrystallization for a constant degree of cold deformation—i.e., the results obeyed recrystallization law (ii). To give an example, the time to reach complete recrystallization at 650◦C with 42% CW only took 15 seconds whereas for the same amount of deformation at 450◦C it took 16 minutes to reach complete recrystallization. In accordance with recrystallisation law (iii)—which states that increased strain on the metal decreases the annealing temperature—the time to reach complete recrystallization at 450◦C 21% CW was 4 hours whereas at 42% CW at the same annealing temperature it only took 15 seconds to reach complete recrystallization."

 

[Tokay444]

I just left a plant tour at Peterson Brass and they fully anneal the entire case no less than 3 times during the drawing process, and the neck and shoulder area 3 additional times before final inspection. They have a Rockwell tester in the process inspection room, as well as microscopes. They have an AMP Annealer they use during cartridge proofing, and say that it anneals quite well.