Do bullets heat treat without arsenic?

[Canuck Bob]

My research into heat treating bullets has me a bit confused.

Please correct me if I'm wrong.

Bullets containing antimony will heat treat without arsenic. In some articles the arsenic improves the hardening time curve but antimony alloys still harden.

Do I understand this correctly?

[DukeInFlorida]

That's the way I also understand it.

It's the antimony that's important.

[cbrick]

Yes, you could HT lino that has no arsenic (don't know why you would want to) because of the antimony. Adding a trace of arsenic would greatly increase the amount of hardening well past what the percentage of antimony would suggest.

The percentage of antimony will control the age hardening time curve. A 4% antimony alloy will reach final hardness sooner than a 2%, 6% quicker than 4% etc.

Rick

[Canuck Bob]

Thanks Rick,

What is the time curve for hardening at 2-4-6% Antimony?

[cbrick]

Thanks Rick, What is the time curve for hardening at 2-4-6% Antimony?

[smilie=l: Your looking for scientific set in stone data from second hand scrounged metals? :shock:

All of the other metals in your alloy will also effect the time curve, most notably tin. The higher the percentage of tin the slower the age hardening time (also the faster the age softening but this is fairly slow). This is part of the reason the tin percentage should not be higher than the Sb in Pb/Sb/Sn alloys. A Sb alloy of 2% or less could take a couple of weeks to reach it's max, a 6% much quicker.

In general a Pb/Sb alloy of around 4-6% should be near it's max strength in 2-3 days with minor and slow increases after that as long as the Sn percent is at 2-3% or less. The first alloy listed in my thread on WW and Roto Metals Super Hard was 14 BHN in two days and 15 BHN in three days. http://castboolits.gunloads.com/showthread.php?t=86349. This alloy has equal Sb/Sn. I expect it to reach 16 BHN by the end of the week but it should be close enough now that any other changes will be minor.

Tonight I will make another alloy with 15 pounds SWW, 2 pounds Super Hard (94.3% Pb, 3.7% Sb and 2% tin). I expect this to be 16-17 BHN (my goal anyway) in about three days with very minor increases after that.

Hope this helps.

Rick

[Canuck Bob]

Thanks again Rick,

I do suffer from the affliction, paralysis by analysis.