I just finished annealing some Lapua brass (6.5x47) and noted a pink color just below the shoulder where usually a light blue color appears. I also noted that as soon as I applied flame to the brass (within a second or two) a light green color appeared in the flame (zinc disintegration I assume). My normal process is to clean the necks with steel wool, then anneal the brass before resizing and cleaning. The brass was turned in a drill and dropped into an aluminum pan as soon as the neck mouth started to turn pink. The brass has been annealed several times and has been loaded 11 times without evidence of stress. I'm very interested in knowing if anyone has seen this before and what did you with the brass.
Pink color on freshly annealed brass
- Thread starter cruiser49
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jonbearman
I live in new york state,how unfortunate !
That pink looks like that is where part of the flame was concentrated while heating. If you cant crush it with extremely light pressure from a pair slip joint pliers,I would use it.
could be the photo, but the brass forward of the pink doesn't look any different from that below the ring. i use a hand held flame and spin the cases and get a distinct bluish/grey color in the neck and shoulder, fading to a red/purple transitioning into normal brass color. i compare my brass to a new lapua and they are sometimes impossible to tell which is which. any chemical residue that could be on your brass?
Color of annealing is not a good indicator of how well the process worked. I have seen this color and I think a lot of it is affected by how clean the brass is and what contaminants is on its surface when it was cleaned.
Here is what the Bench-Source Annealing Manual says about this “The surface condition also plays a part in the looks of an annealed caseâ€
Here is what the Bench-Source Annealing Manual says about this “The surface condition also plays a part in the looks of an annealed caseâ€
Killshot
X's matter....but 10s win (but damn, Xs feel good)
I never use exterior color as a determining factor, too many variables in brass makeup from manufacturer to manufacturer. Those cases look underdone to me. Best to confirm with Tempilaq and a infrared thermometer.
Tom, your comm'l firm used natural gas due to its lower cost most likely. Propane has double the BTU(energy) per cubic foot that natural gas has but it is more costly.
FWIW the maker of the Bench-Source machine recommends against MAPP gas as well.
Tom, your comm'l firm used natural gas due to its lower cost most likely. Propane has double the BTU(energy) per cubic foot that natural gas has but it is more costly.
FWIW the maker of the Bench-Source machine recommends against MAPP gas as well.
MAPP gas is way too hot. With 308 brass, two regular torches with the BenchSource and the flames turned down and the torches moved way back, I am having a tough time getting the time to 4 seconds. Ended up doing 3 seconds which is still within their prescribed time but frankly would like it to be a little longer so that the brass can rotate around the two torches a bit longer to get more even annealing. Actually thinking about running them through twice.... ;D Not immediately but after they cool down.
jonbearman
I live in new york state,how unfortunate !
You do not need to anneal twice back to back imho.You could easily overanneal them as you vaporize small particles of trace metal;s in the mix that make it as strong as it is today.
Well, I am glad you posted because that is exactly my question.jonbearman said:
To be fair, everything I know up to now says that annealing is not cumulative but only temperature dependent. If this is true, you can anneal something a 100 times and its effects does not add up (as long as you let it cool to room temps in between). If it is indeed cumulative, then what you say is true.
So what does the experts say?
Killshot
X's matter....but 10s win (but damn, Xs feel good)
From my admittedly modest understanding of mettalurgy is that is correct, jlow.
For the first couple of dozen lots I annealed, I had the torchheads moved all the way back from the plate and a fairly long flame with the end of the flame about 1/2" from the caseneck. The results were good but I thought the 5-8 seconds (cartridge dependent) was too long.
I spoke to Dave Dorris (maker of Bench-Source) and with his recommendation I moved the heads closer, reduced the flame and put the end 1/4" from the caseneck. Now the dwell times are 2.75 to 3.5 seconds and the results are equal or better than what I got before.
Lapua cases anneal the "best" by far. I do customer work so sometimes the brass I'm doing isn't Lapua and I'll need to vary dwell times from what Lapuas would require. The machine makes it easy.
Can't imagine doing this with a drill and a socket.......
For the first couple of dozen lots I annealed, I had the torchheads moved all the way back from the plate and a fairly long flame with the end of the flame about 1/2" from the caseneck. The results were good but I thought the 5-8 seconds (cartridge dependent) was too long.
I spoke to Dave Dorris (maker of Bench-Source) and with his recommendation I moved the heads closer, reduced the flame and put the end 1/4" from the caseneck. Now the dwell times are 2.75 to 3.5 seconds and the results are equal or better than what I got before.
Lapua cases anneal the "best" by far. I do customer work so sometimes the brass I'm doing isn't Lapua and I'll need to vary dwell times from what Lapuas would require. The machine makes it easy.
Can't imagine doing this with a drill and a socket.......
rvn1968 said:
Interesting. I've experimented with other heat sources for annealing and noticed that the color change isn't the same as it is propane. I haven't thought about it a whole lot about it but I assumed it had to do with the temperature of the flame and/or how hot the the surface of the case was getting. Maybe it's just the additive causing it. Either way it strikes me as similar to reading primers...
I see both types of coloring in the same batch of brass heated with the same source sometimes. It could be something as simple as moisture on the surface of the brass (i.e. from lube) which oxidize in the heat.
Copper which is a component of brass has two oxidation states – cupric oxide which is black in color which is what we are usually familiar with that causes “tarnishingâ€, and cuprous oxide which is red in color. This one is less often seen but people who do SS media cleaning sees it more often since only cupric oxide is dissolved by the citric acid in Lemishine but the cuprous oxide is left which gives you that pink brass. It’s a frequent question in the SS media threads.
Copper which is a component of brass has two oxidation states – cupric oxide which is black in color which is what we are usually familiar with that causes “tarnishingâ€, and cuprous oxide which is red in color. This one is less often seen but people who do SS media cleaning sees it more often since only cupric oxide is dissolved by the citric acid in Lemishine but the cuprous oxide is left which gives you that pink brass. It’s a frequent question in the SS media threads.
As brass gets annealed, it gets softer, the hotter the flame, the softer the brass.
The idea is to take out that hardening from firing but only soft enough to get a consistent shoulder bump and neck tension, and also to reduce the chance of neck splits.
If you anneal with too hot a flame, the neck will be too soft to hold the bullet and the heat may also travel down to the head of the case and a soften head is a candidate for a KB.
The idea is to take out that hardening from firing but only soft enough to get a consistent shoulder bump and neck tension, and also to reduce the chance of neck splits.
If you anneal with too hot a flame, the neck will be too soft to hold the bullet and the heat may also travel down to the head of the case and a soften head is a candidate for a KB.
i'v asked this before with no response. as i understand annealing, the heat realigns some aspect of the microstructure of the brass that is changed by use and time. this structural change hardens the brass and annealing corrects it. some "anneal" after each firing. is this structural change there after only one firing? is there a "crush" test for a brass case to measure the softening effect of the process and can this test determine if no. 1... is the brass actually annealed and no. 2... does annealing after one use actually alter the brass?
atmosphere & annealing / Volatilises & Boudouard reaction
Annealed in a controled atmosphere chamber. Click file. 22pdf See part 3.2 http://heattreatment.linde.com/International/Web/LG/HT/like35lght.nsf/repositorybyalias/wp_semifnshd_22/$file/22.pdf
- Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI
when work hardened. I would guess, if you burn the zinc out of the brass, it becomes pink. Pure copper would be weak. :-\
Annealed in a controled atmosphere chamber. Click file. 22pdf See part 3.2 http://heattreatment.linde.com/International/Web/LG/HT/like35lght.nsf/repositorybyalias/wp_semifnshd_22/$file/22.pdf
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI
when work hardened. I would guess, if you burn the zinc out of the brass, it becomes pink. Pure copper would be weak. :-\
The confusing part about this is that there's two forms of annealing "partial" or "recovery" annealing (which is what we do as reloaders) and "full" annealing which is what's generally referred to by annealing but is not what we want to do in our situation.
When the brass is worked, the nicely aligned rows of atoms dislocate and cross each other so they're no longer free to move back and forth. The effect is the ductility of the material decreases, it doesn't bend as easily. "Harden" is just the slang term we use. Actual hardness is a different property. When we apply heat, we're providing energy for those dislocated rows of atoms to rearrange themselves back to a lower energy state. This is what we're accomplishing with partial annealing. Full annealing is a completely different process involving changes to grain structure which ruins the cases for our purposes.
Picture holding two 2x4's parallel together. You can slide them back and forth. Now if you cross one below the other in a x pattern, you can't move them back and forth against each other. That's what's happening on an atomic level. You can see the same effect if you bend a paper clip. When you bend the wire out and then try to bend it back there's a stiff spot and it won't bend back to it's same shape. You've strain hardened the material the same as we do with cases. Bend it back a forth a few times and it breaks.
good explanation. same question...will firing a properly annealed case once produce enough of this described reorientation to be corrected by annealing? just wondering if some are spending a LOT of time "annealing" for no real benefit. i anneal after 6-10 firings and believe i can detect an ease of trimming and when necking down some 6br cases to 22 cal after they were fired as a 6br, i believe i can detect an easy neck turning....not really sure.
Yes, every time the brass is sized and fired the dislocation density goes up and the brass becomes less ductile. You can prove it to yourself by doing something like a large neck-up. Take a new .22 caliber case (annealed from the factory) and neck it up 7mm or 30 cal. Then do it again with a once fired case. If you do a few of them you'll see more neck splits with the fired cases because the firing process reduces some ductility each time.
As to your underlying question as to whether or not there's an actual benefit on paper to annealing more frequently. I'm not a benchrest shooter but it's noticeably improved the accuracy of my guns. Instead of being skeptical, just test it. Take your 10x brass and freshly annealed brass and compare them side by side. If you don't see an improvement then don't do it. If you do, you have your answer.
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