Anneling?
- Thread starter .264 Win Mag
- Start date
Harold Manback
CGN Regular
Brass work hardens with each use, expanding to fit the chamber and then getting squeezed back into spec by the sizing die. Annealing brass makes it softer again. Some people put them in a cookie pan with water so that just the case mouths are above the water level and heat them in the oven. When they reach the desired temp, (indicated by color I think) they shake the pan and they get quenched, or rapidly cooled, by the water. I have never annealed cases before, I will try to post a link to a article I read about it, if I can find it.
BattleRife
CGN Ultra frequent flyer
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All metals have a structure of crystals. The action of working brass (expansion during firing followed by squeezing in the reloading die) breaks and deforms those crystals.
The ability of any metal to deform (bend, stretch etc.) depends on the ability of the atoms to slip in planes through the crystals. When crystals are deformed, the slip planes don't align, and it is much more difficult for the metals to deform as a whole. This means it takes more force to bend them , which means they are harder and stronger, but much more likely to crack instead of deform plastically.
Annealing is the process of heating metal to allow the crystals to recover some or all of their regular form. The annealing temperature of cartridge brass is usually given as 425C-750C for industrial purposes. The home annealer can likely achieve good results with somewhat lower temperatures, but a really good, reliable, well-controlled annealing method has yet to be settled on for the home loader.
The ability of any metal to deform (bend, stretch etc.) depends on the ability of the atoms to slip in planes through the crystals. When crystals are deformed, the slip planes don't align, and it is much more difficult for the metals to deform as a whole. This means it takes more force to bend them , which means they are harder and stronger, but much more likely to crack instead of deform plastically.
Annealing is the process of heating metal to allow the crystals to recover some or all of their regular form. The annealing temperature of cartridge brass is usually given as 425C-750C for industrial purposes. The home annealer can likely achieve good results with somewhat lower temperatures, but a really good, reliable, well-controlled annealing method has yet to be settled on for the home loader.
- Location
- In the middle of gopher country
There is an excellent article on annealing in "Gunners Den".
It is available via internet
Cheers
It is available via internet
Cheers
Annealing brass
My home method is as follows. Take the spent primers out of the cases. set them uprigtht in a pan, of some sorts, and pour water in to a depth of maybe 3/4 of an inch, for 30-06 class empties. Use a propane torch, the type you would solder with, and heat the tops of them, one by one. When a neck glows dull red, upset it in the water.
This does an excellent job. The base of the case must never be heated, because you want the base to stay hard. Brass carries heat so well, that even with just the base in the water, it takes a lot more heating than it would without the water.
If they are too close together in the pan it will only be a matter of time until you accidentaly knock them over by the domino effect!
So, is it worth the effort, in order to get a few more loadings out of them? I doubt it, unless they are special, or maybe excessively expensive.
My home method is as follows. Take the spent primers out of the cases. set them uprigtht in a pan, of some sorts, and pour water in to a depth of maybe 3/4 of an inch, for 30-06 class empties. Use a propane torch, the type you would solder with, and heat the tops of them, one by one. When a neck glows dull red, upset it in the water.
This does an excellent job. The base of the case must never be heated, because you want the base to stay hard. Brass carries heat so well, that even with just the base in the water, it takes a lot more heating than it would without the water.
If they are too close together in the pan it will only be a matter of time until you accidentaly knock them over by the domino effect!
So, is it worth the effort, in order to get a few more loadings out of them? I doubt it, unless they are special, or maybe excessively expensive.
I do mine in a casting pot in molten lead. Set my temperature at 700. Remove primers first. Hold case head with your fingers, submerge the neck. When the case head gets warmer than you like to hold, remove, shake any lead free from neck and drop in water to stop annealing moving down the case. Brass does not harden when quenched like steel does. Works for me.
- Location
- Somewhere on the Hudson Bay Coast
My system is to hold the case in my fingers, with the case mouth angled upwards and rotate it in a gas flame directed at the shoulder and neck. This system has two advantages. First, when the case is too hot to hold you drop it into the water, so the heat does not transfer to the head of the case and soften it. Rotating the case in the flame heats the case evenly on all sides, so the brass softens uniformly.
There might a greater advantage to annealing than just extending the case life. If with each subsequent firing and resizing the case neck hardens, it would follow that the bullet pull weight will change. There is a chapter in the A-Square manual that claims that velocity increases with each subsequent firing - resizing cycle, and that brass should be annealed every second firing for the best uniformity. I find this intriguing and I intend to conduct an experiment to see the results for myself.
I will use 3 new cartridge cases selected by weight. Each case will be full length resized and reloaded with a proven accurate load with each firing. One case will be annealed with each firing, one case will be annealed every other firing, and one case will not be annealed. The prediction is that the case that is not annealed will show an increase in velocity with each subsequent firing. It will be an interesting experiment, but I'm going to wait for warmer weather.
There might a greater advantage to annealing than just extending the case life. If with each subsequent firing and resizing the case neck hardens, it would follow that the bullet pull weight will change. There is a chapter in the A-Square manual that claims that velocity increases with each subsequent firing - resizing cycle, and that brass should be annealed every second firing for the best uniformity. I find this intriguing and I intend to conduct an experiment to see the results for myself.
I will use 3 new cartridge cases selected by weight. Each case will be full length resized and reloaded with a proven accurate load with each firing. One case will be annealed with each firing, one case will be annealed every other firing, and one case will not be annealed. The prediction is that the case that is not annealed will show an increase in velocity with each subsequent firing. It will be an interesting experiment, but I'm going to wait for warmer weather.
BattleRife
CGN Ultra frequent flyer
- Location
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No, the cooling rate is completely inconsequential to the process. Box cool them over a period of hours or drop them into a doer of liquid nitrogen to quench them, the hardness will come out the same. The anneal is determined by the recovery of the stable crystalline structure, and that is driven by time at temperature. "Five seconds at 400 C". "30 minutes at 340C". These are the important factors in the annealing heat treatment.
People have a tendency to think about steel when the processing of metal comes up. Don't. There are something like 70 metals on the periodic table of elements, and iron is almost unique among them in terms of several of its properties.
The work hardening of the necks and shoulders comes from repeated firing and re-sizing. Annealing softens the brass.
"...a neck glows dull red..." The brass doesn't have to be red hot. Heat the necks and shoulders, only, until the brass changes colour and tip 'em over. The water should come up to just below the shoulder of a bottle necked case.
"...a neck glows dull red..." The brass doesn't have to be red hot. Heat the necks and shoulders, only, until the brass changes colour and tip 'em over. The water should come up to just below the shoulder of a bottle necked case.
