Addendum re: Age hardening

by Hoot , Diversityville, Liberal-sota, Friday, February 20, 2015, 06:07 (3569 days ago) @ Hoot

After much reading, it seems that cartridge brass, Cu-Zn alloy, does not 'age harden'...at least, near as I can 'cipher it. It's mostly the beryllium copper alloys used for springs and electrical contacts. It's properly called precipitation hardening and there's reams of technical data, phase diagrams and whatnot out there in the ether.

This would then leave a couple of possibilities: improper/no annealing or chemical contamination (mercuric primers, ammonia cleaning, etc.). Storage conditions may also be a possibility but that isn't very certain.

The brass all looked in good shape, so no obvious corrosion evidence. There is also no discoloration associated with annealing although that is easily polished off.

FWIW...