AMP 3 digit code

[Chiquita]

I am getting ready to anneal once fired 7.62M1A brass. I annalyzed (4) cases and had three different codes 153, 155 (twice), 157.
What does the code mean? Hotter/lower annealing temperature?

When I look up their website,my case is not listed, however, a Federal case code is a two digit code?

What am I doing wrong and/or not understanding?

Edward

 

[piie]

What pilot did you use for your brass? That is super important since it assures the correct depth into the annealer.

The Aztec codes are like “shortcut” custom codes that is arguably more accurate than the lookup codes. My assumption is that your 7.62 “M1A” is std 7.62x51 NATO, or .308
Start by ensuring that you used the correct pilot (the 308/260/7mm-08/243 one).

if you did that, then the 155 reading you got from before should be good to go. When you start up the machine, just go into aztrc mode and enter that code, machine will then apply correct settings.

lookup some videos on Youtube, AMP, Gavintube, Eric Cortina and FClass John have all made comprehensive howto videos

 

[JimSC]

In the AMP manual it tells you to use a ball micrometer to get the neck thickness of several pieces of brass and use the average. Rather than destroy another piece of brass I would do is use the 155 setting for that particular lot. I don't think a difference of plus or minus two will make much of a difference

edit-= here is a link to the AMP annealer page on neck wall thickness and what role it plays in the settings

Induction Annealing Case Necks | Measuring Neck Thickness

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

 

[RegionRat]

Edward, the idea is that you can take an average case for your batch and use it for the AZTEC code.

You can read their paper to get a feel for how the highest or lowest samples of a batch with lots of spread would respond. Pretty clear that the best brass stats would produce the most consistent annealing. Getting the tool number punched in and generating a code by sacrificing your average case is pretty straightforward.

Then later on, you can "adjust" the annealing up or down by stepping that code up or down if you so choose. Annealing isn't just temperature, it is time-temperature so these codes affect both. All of that is in their write ups.

I am curious why you did that four different times? Were you generating codes on brass with variations, or just seeing how repeatable the code is? How much variation do you have on your brass?

 

[JimSC]

it is best to prep the brass for annealing by turning the necks so that the brass has a consistent amount of brass to anneal each time. The AMP uses an electromagnetic field to transfer energy to the brass where it changes to heat energy. In the Aztec analysis mode it is computing how much energy it needs to transfer to achieve a temperature of 550C where flash annealing occurs. Too long at that temperature and excessive grain growth occurs so it is better to err a bit on the conservative side if anything. Between 500C to 550C annealing will still occur but will take up to an hour which would overheat and soften the web of the case. That is the magic of the AMP, it can heat the brass to exactly the temperature needed to flash anneal for the exact amount of time for the perfect anneal every time if fed brass with a consistent amount of mass in the neck area

 

[whatsupdoc]

it is best to prep the brass for annealing by turning the necks so that the brass has a consistent amount of brass to anneal each time. The AMP uses an electromagnetic field to transfer energy to the brass where it changes to heat energy. In the Aztec analysis mode it is computing how much energy it needs to transfer to achieve a temperature of 550C where flash annealing occurs. Too long at that temperature and excessive grain growth occurs so it is better to err a bit on the conservative side if anything. Between 500C to 550C annealing will still occur but will take up to an hour which would overheat and soften the web of the case. That is the magic of the AMP, it can heat the brass to exactly the temperature needed to flash anneal for the exact amount of time for the perfect anneal every time if fed brass with a consistent amount of mass in the neck area

I thought Aztec mode destroyed the case and that would take a temperature higher than 550C?
Where did you get the information that AMP takes the case neck to around 550C?

Funny thing is that is very close to the temperature I found works well when I used to salt bath anneal not
the 750F most were using.

 

[RegionRat]

Between 500C to 550C annealing will still occur but will take up to an hour which would overheat and soften the web of the case.

Jim, I'm not sure where you heard that it takes an hour at 550C to anneal cartridge brass, but other than calling it here so it doesn't get repeated it isn't important. Was this a typo?

Cartridge brass begins to recrystallize at about 530 F, which is just 277C. This is why we say to keep the body below 400F.

A little recrystallization isn't the same as getting the necks into the region of 950F (510C) for long enough to hit the numbers, but that is where cartridge necks are typically annealed plus or minus a little for specific brass and tooling.

Every specific production line has to be adjusted a little for the actual brass and heat flux rate. Those adjustments were never independent levers, in other words I didn't get to change the peak temp without increasing the time, they are somewhat coupled due to the circumstances of the methods. But we only stayed in the regions of 500C to 550C for moments measured in seconds and milliseconds, not hours.

Getting hardness back down where we want it in the neck is a time temp issue and the AZTEC codes will vary based on the sample you test, that was all that matters today.

The question still remains as to what the OP was testing and why.

Funny thing is that is very close to the temperature I found works well when I used to salt bath anneal not
the 750F most were using.

You are correct.
It would take too long at 750F using a bath. If folks were running that low, at best what they were seeing is some amount of recrystallization which is okay as long as they ran it the same every time. It just isn't the same as hitting the original spec numbers for the neck.

 

[JimSC]

the Aztec mode does take it beyond 550C when in analysis mode. Some of the case necks that were used for analysis appear to have spots that have melted slightly on the necks. The 550C number comes from the Copper Development Association. That is the temperature needed to perform a flash anneal. At 750 F the brass is only stress relieved and softened slightly. If you want to fully anneal between 500C- 550C the temperature needs to be maintained for 30 min to an hour which of course would ruin the cases for shooting purposes. When in normal annealing the AMP heats the neck up to 550C and possibly slightly above but only for a second or so to perform the flash anneal.

edit found a source not behind a paywall. Download the linked pdf. On page 15 the chart shows 5 minutes at 550C. This was for a test coupon .125 thick. Your cases necks are appx .015 thick which may be why the AMP only takes a couple of seconds. Either that or the AMP may heat the necks slightly above 550

Recrystallization Behavior of 70/30 Brass

Cartridge brass undergoes significant changes in mechanical properties as a result of cold work. These changes are effectively reversed in the annealing process returning the metal to its precold-worked state. The major goal of this study is to

www.academia.edu

 

[JimSC]

Jim, I'm not sure where you heard that it takes an hour at 550C to anneal cartridge brass, but other than calling it here so it doesn't get repeated it isn't important. Was this a typo?

Reread my post, I did not say it took an hour at 550C. My statement is that it takes up to an hour to get a full anneal if the temp is between 500 and 550C. At 550 you get flash annealing which only takes a second or two.

edit- annealing actually begins to occur around 400 C and at 250 C - 300 C the brass is only stress relieved

There is stress relief, softening, annealing, and flash annealing. Each of which requires higher temperatures.

 

[Chiquita]

What pilot did you use for your brass? That is super important since it assures the correct depth into the annealer.

The Aztec codes are like “shortcut” custom codes that is arguably more accurate than the lookup codes. My assumption is that your 7.62 “M1A” is std 7.62x51 NATO, or .308
Start by ensuring that you used the correct pilot (the 308/260/7mm-08/243 one).

if you did that, then the 155 reading you got from before should be good to go. When you start up the machine, just go into aztrc mode and enter that code, machine will then apply correct settings.

lookup some videos on Youtube, AMP, Gavintube, Eric Cortina and FClass John have all made comprehensive howto videos

I used pilot #11.

Thank you for the reply.

 

[Chiquita]

Edward, the idea is that you can take an average case for your batch and use it for the AZTEC code.

You can read their paper to get a feel for how the highest or lowest samples of a batch with lots of spread would respond. Pretty clear that the best brass stats would produce the most consistent annealing. Getting the tool number punched in and generating a code by sacrificing your average case is pretty straightforward.

Then later on, you can "adjust" the annealing up or down by stepping that code up or down if you so choose. Annealing isn't just temperature, it is time-temperature so these codes affect both. All of that is in their write ups.

I am curious why you did that four different times? Were you generating codes on brass with variations, or just seeing how repeatable the code is? How much variation do you have on your brass?

I was trying to see if the code will be different. The brass that I have was from factory rounds that I hav eshot in the past three years and so they are different brass lots and hence the different codes.

 

[Chiquita]

Thank you all for your replies. I will watch videos as suggested and turn the necks to be as consistent as possible.

 

[RegionRat]

Reread my post, I did not say it took an hour at 550C. My statement is that it takes up to an hour to get a full anneal if the temp is between 500 and 550C. At 550 you get flash annealing which only takes a second or two.

Between 500C to 550C annealing will still occur but will take up to an hour which would overheat and soften the web of the case.

Jim, didn't mean to put words into your mouth, but was trying to clear up a point with the sentence above.

It would not take an hour on a cartridge neck at 500 to 550C. We flash the neck heat up to those temps and anneal within a blink and it happens to work out that the process goes quick enough to avoid softening the body.

We used the time to infrared glow point as a process control reference point and adjusted up or down from that point. Depending on the emissivity of the metal, it was always just over 500C more or less. From these settings, we plotted microhardness and made slides to look at the grain structure. Each stage was adjusted a little, but they were in fact very close to that initial infrared glow point just depending on the set-ups.

A process that uses the heat flux to get a time to the melt point in that they back away from that event based on empirical tests. As far as I can tell, which is just a guess on my part, AMP goes beyond the glow point in order to get feedback with simple sensors. Infrared is complicated but sensing other events may not be.

Too much misinterpretation of metallurgy has been spread with respect to cartridge necks which are different than the tests or charts published on pucks or billets. The charts for alpha phase cartridge brass are used for other reasons, not for how we anneal the brass on the lines, or how a reloader does it at home. Thin brass necks and pucks are very different in terms of their time-temp issues. YMMV

 

[RegionRat]

I was trying to see if the code will be different. The brass that I have was from factory rounds that I hav eshot in the past three years and so they are different brass lots and hence the different codes.

Your results are normal and should not be a surprise.

You will want to start keeping a notebook of the brass batches and stats on the weights or direct thickness values to keep yourself organized.

This doesn't mean you must turn necks, or at least not because you would need to for annealing purposes. There are other reasons to turn or not turn necks and you would want to let those other reasons take priority cause you will be fine annealing un-turned necks.

None of the brass in the production lines was as good as turned brass, yet it was all annealed and well within hardness specs on the thick side and thin side, if that makes you sleep easy at night.

 

[JimSC]

Too much misinterpretation of metallurgy has been spread with respect to cartridge necks which are different than the tests or charts published on pucks or billets. The charts for alpha phase cartridge brass are used for other reasons, not for how we anneal the brass on the lines, or how a reloader does it at home. Thin brass necks and pucks are very different in terms of their time-temp issues. YMMV

Not doubting you at all, but it is Interesting that you have found annealing of actual cartridges different than billet or pucks. Other than the mass it the molecular structure would be the same. The lower mass would mean less energy transfer to needed to raise the temp but any changes to the grain should be occuring at the same temps it would seem. Just makes me curious as to the why and yes all my teachers hated me.

As far as having the perfect anneal, so far in my limited experience, two weeks now, with the AMP I have noted no difference in group size or velocity stats from flame annealing. Of course any improvement could be just getting lost in the noise.

 

[RegionRat]

Other than the mass it the molecular structure would be the same.

Not how it works... but you have friends who will explain... and why do I know...
This was where the time I spent in my youth came in handy.... The son of a stone mason/brick layer in the steel mills, I am called RegionRat which is a contraction of two concepts. First, I was raised in the Calumet Region, to many an unpleasant place due to the heavy smokestack mills, foundries, refineries, etc., (not to mention the crime). The second concept is Mill Rat, cause I was raised in the labs of the mills and foundries, thus being a RegionRat to all my suburban friends from cleaner places... A good place to be from... LOL

Before I was recruited to do weapon systems development work, I was already an expert in several metals and alloys. Due to the background I had growing up, I was also a chair of many committees and standards bodies including being a branch chairman of ASTM. So I am not pulling your leg or guessing in terms of cartridge brass annealing.

To prove the accuracy of your fire controls and weapons systems, you have a vested interest in accurate ammo during the live fire testing... thus my direct tie to the ammo folks and several tours of duty at many facilities and labs, not to mention the ones I ran.

What you learn if you spend time making metals and alloys, is that the way different metals react to heating and cooling is fascinating. The ability of steels to form fine Martensitic grain structure for example, gives us some amazing hard steel good for things like bearings or gears for example. That crystal grain structure is similar to the visible nature show we see when we watch frost or snow flakes as an example. Their structure depends on the speed we give the water to "stack" among other things. Do things faster or slower and there is a big effect, even when by our view the temperature changes are small.

Alpha phase brass like cartridge brass doesn't harden like steel by being cooled or quenched rapidly. However, the time it takes to form grain structure is directly related to heat flux and temperature, so in fact the mass does affect our outcome. Thick proportions change the equations, just as thin ones do. The biggest differences being in the time it takes the crystal grain structures to jump state.

We soak those pucks and billets in ovens for hours for studying other properties or running QC checks on raw materials. The hardness of those billet samples and the phase boundary diagrams are not to be confused with what happens when we take little "cups" and deep draw them into cartridges in several steps. The work is annealed more than once and in specific ways in order to get the rims, heads, bodies, shoulders, and necks to specific hardness as we go.

Not sure if you have ever had a chance to read this, but it may contain a glimpse into cartridge making. There are some specific words on the differences between annealing cups versus thinner parts starting on about page 18.

https://ia801603.us.archive.org/28/...tion Making-NRA by G. Frost-(1990) _text.pdf

Hope it makes for good nightstand reading.

Cheers, Dino aka: RegionRat

 

[darkangel_r2]

I am getting ready to anneal once fired 7.62M1A brass. I annalyzed (4) cases and had three different codes 153, 155 (twice), 157.
What does the code mean? Hotter/lower annealing temperature?

When I look up their website,my case is not listed, however, a Federal case code is a two digit code?

What am I doing wrong and/or not understanding?

Edward

Peterson Cartridge Ballistician Testing Data

docs.google.com

Peterson lists the codes for all their brass. You can use this to get you in the ballpark at least.

 

[Ccrider]

Peterson Cartridge Ballistician Testing Data

docs.google.com

Peterson lists the codes for all their brass. You can use this to get you in the ballpark at least.

Interesting. My Aztec code for Peterson 6 dasher is 152. They list 147. Probably not a big deal, but I would go ahead and run the Aztec for my specific lot of brass. I don’t think + or - 1 or 2 maters much. You will get diffent numbers if you clean your necks versus uncleared necks.

 

[Chiquita]

Thank you for your replies.

 

[Chiquita]

Does higher code number mean higher temperature or not necessarily?