Question About Annealing

[Jeff82]

From recommendations on one of my previous threads, I've tried annealling to help standardize the BHN of my bullets. I heat bullets at 325 degrees for one hour and then let them cool in the oven. Works great! I've also heard of people using the same process but with much higher temperatures to harden bullets. And, I've heard of people annealing brass to enhance its life.

Can anyone explain in simple terms why heating at 325 degrees softens bullets and heating at 500 degrees hardens them? Also, has anyone tried annealing brass?

Thanks,

--Jeff

[Smoke4320]

annealing brass will greatly lengthen case life ..but must do it about every 3 firings for hi pressure mag calibers ..

[xr650]

Jeff,
Hardening boolits require quenching in water when hot. The faster you cool the alloy the harder it can be.
Annealing boolits require slow cooling.
Either temp that you specified will harden or soften. Just depends if you quench or cool slow.
Have a day,
Larry

[grampa243]

don't try to anneal brass in an oven. for 1. it would be hard to get it hot enough and 2. you only want to anneal the neck and not the base.

[Defcon-One]

What they said! [smilie=1:

Cooling rate affects grain size! Grain size affects hardness! In a Lead alloy it is the Antimonial grain structure that causes it to harden. You need the Antimony to quench harden. A bit of Arsenic improves the hardening by refining the grain structure further.

I'm pretty sure that to anneal Brass you heat it, then quench it! Brass is affected differently than Lead. And Yes, it is the neck only!