I don't usually anneal new brass (as MD said it's usually done during production), but occasionally have needed to. I've mentioned here before about a recent batch of Lapua brass which clearly showed annealing marks, but cracked necks on a number of pieces on the first firing; those needed to be annealed again. The problem there is that it's not obvious if annealing is necessary until necks start to crack.
Agreed that water quenching after annealing doesn't hurt. I think the reason some have said to do it is to keep the heat from migrating to the case head; in my experience if that's a problem you've gotten the neck and shoulder way too hot anyway (or maybe when working with very short cases). Just looking at material hardness though, brass and copper aren't affected by a water quench so it's fine to do it either way.
When torch annealing I didn't bother to quench, but now that I'm using salt bath annealing, it makes sense to quench because the water rinses the salt off. After thorough rinsing I dry them in the oven at 225° F for about half an hour.
As another point of interest on that topic - another example of different but similar alloys behaving differently with quench is lead bullet alloys. The common lead, tin, and antimony (plus a trace of arsenic) alloys can be hardened by water quenching, but only after aging for several weeks. It remains soft right after quenching but ages harder over time as the crystaline structures grow. High carbon steels on the other hand harden immediately with quenching, as most of us know. Interesting stuff and you have to dig into phase diagrams to really understand what and why of each alloy.
Last edited by Yondering; 05/08/19.
