Hypothetical annealing question?

[eric n]

I start with two pieces of identical brass. Run an expander through both, expanding .020. Then , neck down .010 and expand neck up .005.
If I repeated this process five times, with the difference being... One piece of brass was annealed between each sizing and the other was annealed at the end of the cycle, would they both be the same at the end?

 

[dedogs]

Probably not. It's an imperfect world. And annealing (to some) is VOODOO!

 

[fguffey]

I start with two pieces of identical brass. Run an expander through both, expanding .020. Then , neck down .010 and expand neck up .005.
If I repeated this process five times, with the difference being... One piece of brass was annealed between each sizing and the other was annealed at the end of the cycle, would they both be the same at the end?

eric, a few years ago reloaders claimed they necked sized their cases 4 times after the first firing and then started over by full length sizing and then continued neck sizing for the next 4 firings and then again started over by full length sizing and I always asked how is that possible?

How it is possible to start over by full length sizing when the case has been fired 5 times? And now? They are annealing after every firing? I was over in the Delta West of Memphis, Tennessee; the farmers were complaining about plowing in the delta. I had to ask about the problem; I suggested after all these years they should have had it figured it out by now.

One farmer said he had it worked out; he said he went in at noon to eat and it was too wet to plow. He said he went back to plowing after eating and found the field was too dry to plow leading me to believe there was no right time to plow.

I suggest a reloader should not over work his brass. I am the fan of reducing case travel.

F. Guffey

 

[jlow]

The most impressive demonstration of work hardening I have ever seen is a video of a lady holding a brass rod. She bends the rod 45 degrees seemingly with ease, and then tried to bend it back straight and could not. See here:

 

[eric n]

The most impressive demonstration of work hardening I have ever seen is a video of a lady holding a brass rod. She bends the rod 45 degrees seemingly with ease, and then tried to bend it back straight and could not. See here:

Thank you for posting that video jlow, it gives me direction in testing for myself with some flat bar.

F. Guffey- I take great pains in not overworking my brass.
The question came from my first time making a false shoulder for a dasher.
Expand and turn, neck up to 6.5, my Forster 6br f/l die is stupid tight in the neck so it needed to be expanded back up again to not shave bullets. I wasn't comfortable with how much work hardening was occurring so I stopped after a dozen and began annealing between each step. I guess I will find out if it matters eventually.

 

[RonAKA]

I start with two pieces of identical brass. Run an expander through both, expanding .020. Then , neck down .010 and expand neck up .005.
If I repeated this process five times, with the difference being... One piece of brass was annealed between each sizing and the other was annealed at the end of the cycle, would they both be the same at the end?

I think the short answer is that if you don't create a low cycle fatigue crack in the microstructure in the process, then yes they will both be the same. If you physically crack the material, you can't fix that by annealing. That is the basic logic behind annealing every 5 firings, or whatever rule of thumb you come up with. You are trying to anneal before permanent (cracking) damage is done.

The difference between annealing every 5 times vs every time you fire is that when you use a case that has been fired 1, 2, 3 etc times without annealing, it is getting stronger each time. Each time you stretch the material to yielding you increase the yield strength. That can cause changes in neck tension over the 5 firing cycle. Those who anneal every time, will be dealing with the same strength material every time -- providing they anneal at the proper temperature for the right amount of time. You don't have to get the temperature much under the ideal 750-800 degrees to do essentially nothing.

 

[eric n]

I think the short answer is that if you don't create a low cycle fatigue crack in the microstructure in the process, then yes they will both be the same. If you physically crack the material, you can't fix that by annealing. That is the basic logic behind annealing every 5 firings, or whatever rule of thumb you come up with. You are trying to anneal before permanent (cracking) damage is done.

The difference between annealing every 5 times vs every time you fire is that when you use a case that has been fired 1, 2, 3 etc times without annealing, it is getting stronger each time. Each time you stretch the material to yielding you increase the yield strength. That can cause changes in neck tension over the 5 firing cycle. Those who anneal every time, will be dealing with the same strength material every time -- providing they anneal at the proper temperature for the right amount of time. You don't have to get the temperature much under the ideal 750-800 degrees to do essentially nothing.

Thank you for taking the time to reply.