A friend tried annealing for the first time and overheated the cases,the brass will not springback when he seats a bullet,can these cases be saved by reannealing
Annealing question ?
- Thread starter s100whunter
- Start date
They are also now dangerous to use since if they were over heated, the bases were almost certainly also weakened. They should be destroyed to make sure no one else finds them and uses them without realizing the situation. A weakened body or base area of the brass can cause it to separate on firing and damage the gun or injure the shooter.
Thanks all I will get rid of them
I wouldn't assume the case heads were softened and they are not safe to shoot. I would take a pair of pliers and crush an unannealed case and an over annealed case about 1/4 of the case length from the rim and see if there is a noticable difference in the force to collapse the case. Try it in the shoulder area too. The head area would have to be above at least 750F for 5-10 seconds to get a minimal hardness change. It's hard to say how many times you need to expand and size the neck to get a decent hardness. The shoulders probably won't be cold worked enough to get the hardness back up. After annealing one case you should have tried the pliers test on the necks. How far does the oxidized color go down the case from the neck area? If you don't have confidence in the safety of the cases I would get rid of them. You are only issued one set of eyes. Definitley wear OSHA approved safety glasses for all shooting.
How do you know for sure you have over done it?
No you can't "cook" the zinc out. All you are doing is changing the grain structure.
I agree with others, how do you know they are ruined?
I agree with others, how do you know they are ruined?
ridgeway said:
It will depend on just how hot the cases got. But, I have over heated cases a time or two and restored them with the above method. It usually take three or four passes through the die and mandrel, but they usually harden again. It's unlikely that they have been damaged to the point of being unsafe unless they were heated all over. Since I wasn't there, I can't say for certain. My suggestion would be to try a few and use the vise grips to check on springback. I suspect you'll get good results.
Rick
Raythemanroe
Bullet Whisperer
s100whunter said:
You mean your friend
Ray
savage10shooter said:
Yes you can. Ever tried to TIG-weld brass?
If you get brass hot enough, zinc will offgas, leaving a white powder which is zinc oxide, the same stuff you smear on your nose to prevent sunburn.
Zinc boils at a lower temperature (1665°F) than copper melts (1984°F).
That said, I'm with the others -- after checking the heads for being too soft, I would try to work-harden them back up in the sizing die. If that worked to re-harden them, I would then use a bent paper clip to check a few cases for a "head separation ring" on the inside of the case just forward of the head (if the entire case was softened, running it through the FL sizing die several times could conceivably create such a ring, I think) and if they passed that test, I'd probably load a couple and shoot them and check for loose primers, which could indicate that the heads got annealed and may be too soft to be safe. Good luck and don't forget those safety glasses!
If you heated your cases long enough to get a bluish green flame you've not only burned out the zinc (which doesn't change the flame color) but you've started burning the copper too.
You might be able to work harden the case necks enough to make the case usable but chances are it's history if you burned copper as well.
You might be able to work harden the case necks enough to make the case usable but chances are it's history if you burned copper as well.
savagedasher
Banned
Two kinds of Annealing Stress Relief annealing And Homogenize annealing . What one is the reason for annealing ?
Larry
Larry
savagedasher
Banned
That would be Homogenize annealing. LarryWebster said:
General description of homogenizing. In bronze, steel and other ingot cast metals you get segregation of elements like sulphur , phos and many other elements. This is because the ingot cools and solidifies from the outside and the center core last. There is a temperature gradient in the molten metal and the solubility of the alloy elements vary with temperature. This results in what’s called dendritic segregation. The center of the ingot has a higher % of alloy elements than the outer portions. Holding the metal for a long time at high temp allows these elements to diffuse evenly throughout the metal so you have the same properties throughout the part. Homogenize anneal combines homogenizing and annealing in one heat treatment since both treatments are in the same temperature range. Does not apply to cartridge brass since 30% zinc will completely dissolve in molten copper at any temp.
People need to quit getting hung up on metallurgy. You simply heat the neck shoulder area for 5-10 seconds at somewhere between 750-1200F and you’re finished. Higher temp shorter time. Read all the post it’s all in there. The normal reason for annealing is to reduce the hardness and make the metal more ductile for some kind of machining or die forming process.
Probably one reason why zinc is limited to 30% in cartridge brass.
http://www.engineeringarchives.com/les_matsci_unlimitedandlimitedsolubility.html
If a small amount of liquid zinc is added to liquid copper, a single liquid solution is produced. When that copper-zinc solution cools and solidifies, a single solid solution having an FCC structure results, with copper and zinc atoms randomly located at the normal lattice points. However, if the liquid solution contains more than about 30% Zn, some of the excess zinc atoms combine with some of the copper atoms to form a CuZn compound. Two solid phases now coexist: a solid solution of copper saturated with about 30% Zn plus a CuZn compound. The solubility of zinc in copper is limited. The solubility increases with increasing temperature.
People need to quit getting hung up on metallurgy. You simply heat the neck shoulder area for 5-10 seconds at somewhere between 750-1200F and you’re finished. Higher temp shorter time. Read all the post it’s all in there. The normal reason for annealing is to reduce the hardness and make the metal more ductile for some kind of machining or die forming process.
Probably one reason why zinc is limited to 30% in cartridge brass.
http://www.engineeringarchives.com/les_matsci_unlimitedandlimitedsolubility.html
If a small amount of liquid zinc is added to liquid copper, a single liquid solution is produced. When that copper-zinc solution cools and solidifies, a single solid solution having an FCC structure results, with copper and zinc atoms randomly located at the normal lattice points. However, if the liquid solution contains more than about 30% Zn, some of the excess zinc atoms combine with some of the copper atoms to form a CuZn compound. Two solid phases now coexist: a solid solution of copper saturated with about 30% Zn plus a CuZn compound. The solubility of zinc in copper is limited. The solubility increases with increasing temperature.
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