Clancy, the OP asked the question of Over Annealing Brass!!! And yes, at too high an annealing temperature, the alpha phase can be affected as well as getting too much TWIN GRAINS!!! And, too high a temperature can make the neck too soft too!!
Over Annealing ?
- Thread starter Old Navy
- Start date
Clancy, the OP asked the question of Over Annealing Brass!!! And yes, at too high an annealing temperature, the alpha phase can be affected as well as getting too much TWIN GRAINS!!! And, too high a temperature can make the neck too soft too!!
Clancy
Silver $$ Contributor
Yes sir we decided he over annealed it about 3 days ago. He’s already trashed it. Lesson learned.
Webster:
Here is a master thesis of a student doing research at Norma Brass!!
This is for a MS degree!!! And it deals with 308 and 300 Win Mag brass annealing!!!
THESE IS A GREAT READ FOR RELOADER CARTRIDGE BRASS ANNEALING!!!
IT IS A PDF!!!!!! It is loaded with his massive data collected which other other articles don't show!!! Note: Norma uses to different induction powers (wattage)!!
And the time the cases are in those coils is seconds, not minutes or hours!!!
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It's real simple anneal until the neck is red for 1-2 seconds and your finished. It isn't complicated.
I read most of the article. Well done but I cannot relate it to how I anneal with a torch. He states that some of his results were with a 30 minute anneal. Looks like he used times well beyond flash annealing so he could show etched micrographs with grain change.
ELR LVR
Silver $$ Contributor
Let me try to explain what I was saying here another way because it can be confusing.
But if we think of it like doing body work, such as with a hammer and dolly behind the metal
if we hit a body panel with a hammer, it just rebounds back (what we want the brass to do)
But if we put a dolly behind the metal then smack it with a hammer, it pounds into shape
The Chamber acts as a dolly and the powder charge acts as a hammer
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When the brass is allowed to expand without hitting the chamber wall if we have clearance...
....., it rebounds back into shape
If it is hit hard enough to be pounded against the chamber walls, it hammers into its new shape basically then making itself an interference fit which is a line fit caused by friction.
We now have friction causing the clickers.
ELR LVR
Silver $$ Contributor
I think there is a dif between annealing and tempering
which holding for a certain temp at long periods is more a tempering process.
such as if we wanted the brass to have a certain property other than fully annealed dead soft.
One example of this would be.....I make some trigger springs out of beryllium copper
The Mfgr I got the material from is professionally a large business spring maker.
He told me to anneal/ but a more correct term is "temper" the copper at 500F for about 30-45 minutes after forming the spring to reduce work hardening brittleness after forming the coils.
Which would be a big difference from actual annealing which would dead soften the copper making it no longer a spring.
When we decrease hardness by tempering ....we increase toughness.
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No biggee as the 2 may still be called annealing loosely, but when understanding or explaining one method vs the other.... I believe it is good to differentiate the 2 methods defining the one which is held below a critical temp for a longer duration of time
- as Tempering.
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Straightshooter1
Gold $$ Contributor
Nice report there, sincerely, with data on Norma's two different annealing's in their manufacturing process! They're using their induction coils to get to a "range of 350-600°C" in "14-15 sec". Apparently, the student is not doing his own annealing, but analyzing cases from Norma and just reporting on the microstructure (no detail regard temperatures over various time). Because induction heating is so different from radiant heating done in a furnace that you describe, I dare say heating the necks for 15-20 seconds in 650°F (343°C) furnace isn't going to produce the annealing referred to in that report. ¯\_(ツ)_/¯ The only way to tell, is to really have it measured yourself.
Having read various in-depth studies along this line as well as so many variations for flame annealing stated on the internet, is why I decided to do some testing of my own to see what I was getting with my annealing process using a flame annealer. I wanted to share what I found and posted a thread with my results and maybe you missed it??? You many not be interested. . .???, but here's a link anyway in case you are:
Nice report there, sincerely, with data on Norma's two different annealing's in their manufacturing process! They're using their induction coils to get to a "range of 350-600°C" in "14-15 sec". Apparently, the student is not doing his own annealing, but analyzing cases from Norma and just reporting on the microstructure (no detail regard temperatures over various time). Because induction heating is so different from radiant heating done in a furnace that you describe, I dare say heating the necks for 15-20 seconds in 650°F (343°C) furnace isn't going to produce the annealing referred to in that report. ¯\_(ツ)_/¯ The only way to tell, is to really have it measured yourself.
Having read various in-depth studies along this line as well as so many variations for flame annealing stated on the internet, is why I decided to do some testing of my own to see what I was getting with my annealing process using a flame annealer. I wanted to share what I found and posted a thread with my results and maybe you missed it??? You many not be interested. . .???, but here's a link anyway in case you are:
NICE TESTING STRAIGHTSHOOTER1!!!!!!
From your posts, simply forming the neck adds 2 (Webster scale) hardness!!! Interesting!!!! Anneal to 13, form and hit the target 15!!! Nicely done!!!! And you removed the dimple, ready to finish the reloading process!!!! And, you testing is proving annealing is not an exact science but repeatable!!!! Once you know the TIME & TEMPERATURE you're set!!!!! I've been saying this all along!!!!
WAS MY FURNACE ANNEALING??? Yes!!!! Was I achieving my desired softness??? The target and the feel of seating the bullets said I did!!! That is all we had in those days!!!! Most of the cases went well over 25 reloading plus the once fired state of purchase fired in different rifles!!! THE ORIGINAL PURPOSE OF ANNEALING!!! CASE LONGEVITY!!!! Competition reloaders have taken the annealing process to the next level by trying to achieve uniform hardness for a consistent bullet release!!!!!
One thing that we all must all consider is at Norma, and other case manufacturers, they needed higher ductility and lower tensile strength to draw out the cases!!!! Really soft brass by holding the temperature longer!!! A reloader needs higher tensile strength and lower ductility which the case manufacturers provided with their final product!!!! A balancing act on a razors edge!!!!! The true beauty of the 70/30 brass alloy!!!
This is what the shooting sport is all about!!! The big game hunter wants a stiffer neck!!! The varmint hunter want a mild, relative consistant, stiffness in the neck!!! The competition shooter tries to achieve a consist soft neck that just hold the bullet in place!!
And, the methods of getting those types of necks varies!!! Induction coil, induction coil with coolant, torch or multiple torch heads with some having rotational mechanical devices, furnaces with cooling bath, hot salt baths, or (not recommended) hot molten metal baths!!!
Did you catch the student's final analysis, with data, on what caused the softer hardness test result from the 4th day collected samples???? Like I have been saying, the annealing process is not complete, until the cases are rested for a few days and the matrix has settled to a final equilibrium or steady state!!!! Can we speed it up??? My thinking is Yes!!!!!!!!! There are still stresses and stains in the most of the micro regions!!! Think cryogenics!!!! Additional stress relief using a very cold heat sink called Liquid Nitrogen and time!!! After all, what we are doing to change the properties of the 70/30 is applying heat, exciting the electrons into higher orbits (temperature dictates the orbit levels) and then letting them come to an equilibrium as the heat is drawn out and the electrons settle back down to their nature lower orbits!!!
Question: Will setting the freshly Annealed cases in the freezer for a couple of hours speed up the grain growth and reduce the rest time for that complete growth??????
ONLY THE PEOPLE THAT UNDERSTANDS THE TRUE SCIENTIFIC METHOD AND HAVE THE EQUIPMENT AND TESTING DEVICES CAN DERIVE THE ANSWER TO THE ABOVE QUESTION!!!! AND, THE SCIENTISTS THAT HAS THE TIME IN THIS BUSY WORLD!!!
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I think we have heard enough. If you don't understand it by now your hopeless.
Exactly
Straightshooter1
Gold $$ Contributor
Thanks!!!!!!
One of the things I found interesting is when I looked at the Conversion Table where it shows Webster HW of 13 being at ~ Vickers HV of 83 and the 15 being ~ Vickers HV of 99, which I've heard is at the ideal Vickers hardness for the necks. I feel pretty good that I'm well within the ballpark in terms of a good Vickers HV reading.
Uniformity/consistency is really what's it's all about. There can be different ways of achieving it. Like some shooter achieve a pretty good level of that without any annealing.
Yes . . . ENOUGH!!!
Yes, I did catch that. And I'm thinking very interesting, but only in the sense of counting the number of angles on the head of a pin.
Additional growth is measurable, but that amount has no measurable effect otherwise. Like, when measuring my brass that was at 15 right after processing, measuring them now, month's later, they still measure right on 15. . . just like my virgin Lapua brass. 
If there's a technical measurable change over days, it's not enough to make any difference to consistent reloading. IMHOI don't know why it would since it's the larger amount of heat (like above 300°C) that starts to produce grain growth. Upon removing cases from their heat source for annealing, at room temperature, they cool down very fast (like in an exponential curve way) where growth is pretty much arrested. There's a short time after removal from the heat that grain growth still occurs. Applying a heat sink, like liquid nitrogen, I don't think would do anything to "speed up" any grain growth".
Thanks!!!!!!
One of the things I found interesting is when I looked at the Conversion Table where it shows Webster HW of 13 being at ~ Vickers HV of 83 and the 15 being ~ Vickers HV of 99, which I've heard is at the ideal Vickers hardness for the necks. I feel pretty good that I'm well within the ballpark in terms of a good Vickers HV reading.
Uniformity/consistency is really what's it's all about. There can be different ways of achieving it. Like some shooter achieve a pretty good level of that without any annealing.
Yes . . . ENOUGH!!!
Yes, I did catch that. And I'm thinking very interesting, but only in the sense of counting the number of angles on the head of a pin.
I don't know why it would since it's the larger amount of heat (like above 300°C) that starts to produce grain growth. Upon removing cases from their heat source for annealing, at room temperature, they cool down very fast (like in an exponential curve way) where growth is pretty much arrested. There's a short time after removal from the heat that grain growth still occurs. Applying a heat sink, like liquid nitrogen, I don't think would do anything to "speed up" any grain growth".
Are you telling me that some competitive shooters don't anneal and sacrifice case longevity in this new age of high cost brass cases???? How do they rate in the standing??? I not from that world of elite shooters!!!
Thanks for the heads up on measuring the hardness with long rest time!!! You have eased my scientific mind on that issue!!! Might see it with the more accurate Vickers scale!!! But, like you are finding out and I've learned in school and professional life, in certain situation, decimal places are for purists!!! Sometime tolerance can be too tight and don't matter!!! I firmly believe you're on right track with the Webster scale!!
Thank you for sharing your knowledge and experiences!!!!!!!
aim small
HIT BIG
BILL!!!!!!!
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