Why do some consider torch annealing superior to salt?
- Thread starter Mram10
- Start date
GeneT
Active member
‘At dead soft you will have ZERO neck tension to hold the bullet.”
I use an induction heater to anneal brass with and have been trying different shades of red to determine the temp I want the brass. I have taken it to red all the way down into the shoulder and still have plenty of neck tension to hold the bullet. Now to qualify that statement, this is on LC 5.56 brass cases of recent manufacture, and they feed and function in an AR-15.
My PPC and Beggs cases are taken to a slight glow in a low light setting which I’m sure is still well over 800 degrees, and have not seen a reduction in case neck tension.
Now, I don’t claim to know the best way to anneal brass, my reasoning to do it this way has to do with repeatability and time. It takes about 14 minutes to do 100 pieces of brass, and that’s at a leisurely pace. Still, I want to learn what others are doing and why. I have found that with annealed brass, my headspace can be adjusted to the .001 with virtually no spring-back, yet I’m reading that dead soft is not the goal. I’m not up to speed with you guys, so please help me along a little.
Wayne
I use an induction heater to anneal brass with and have been trying different shades of red to determine the temp I want the brass. I have taken it to red all the way down into the shoulder and still have plenty of neck tension to hold the bullet. Now to qualify that statement, this is on LC 5.56 brass cases of recent manufacture, and they feed and function in an AR-15.
My PPC and Beggs cases are taken to a slight glow in a low light setting which I’m sure is still well over 800 degrees, and have not seen a reduction in case neck tension.
Now, I don’t claim to know the best way to anneal brass, my reasoning to do it this way has to do with repeatability and time. It takes about 14 minutes to do 100 pieces of brass, and that’s at a leisurely pace. Still, I want to learn what others are doing and why. I have found that with annealed brass, my headspace can be adjusted to the .001 with virtually no spring-back, yet I’m reading that dead soft is not the goal. I’m not up to speed with you guys, so please help me along a little.
Wayne
I read your sacrilege
It doesn’t make sense that heating brass to 800f doesn’t anneal, salt or not. Every metallurgy table for annealing calls for 800f ish. I have had good results in the press and on paper with the salt. Any red while using a torch is too hot. I’d like to see more info from an unbiased source.
We need a simple equation showing how long it takes to heat the neck area, aka, .015” of brass to absorb 800f deg of heat. I’ll try and look it up
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At one point I had a very precise chart that showed crystal
structure changes in brass as a function of time and temperature.
It used larger pieces of cartridge brass to allow easier sectioning and
microscopic examination of the polished cross sections.
I cannot locate it, and have not found another.
Annealing is a function of both time and temperature.
If you are doing things by hand (like salt bath dipping) you want a slightly
lower temperature to help extend the required time and reduce variation.
An error of 1 second on a 4 second anneal is a lot worse than a 2 second error on a 10 second anneal.
And hardness measurement are a correlated measurement as opposed to cutting and
polishing a brass section and examining it under a microscope to determine the size of crystals in the metal.
structure changes in brass as a function of time and temperature.
It used larger pieces of cartridge brass to allow easier sectioning and
microscopic examination of the polished cross sections.
I cannot locate it, and have not found another.
Annealing is a function of both time and temperature.
If you are doing things by hand (like salt bath dipping) you want a slightly
lower temperature to help extend the required time and reduce variation.
An error of 1 second on a 4 second anneal is a lot worse than a 2 second error on a 10 second anneal.
And hardness measurement are a correlated measurement as opposed to cutting and
polishing a brass section and examining it under a microscope to determine the size of crystals in the metal.