Thanks,
When I read through AMP's statement, I didn't see anything about full annealing versus recovery annealing - maybe I missed it. I just noted the lab tests that measured the degree to which the brass was effected by the two methods.
Is there a short version of what is the distinction between full and recovery annealing?
Which of those two is being accomplished by the candle anneal method?
Thanks,
Rex
They don't mention anything specifically about the differences in their articles that I know of but I haven't looked at their website in a while.
In a nutshell, there's two basic mechanisms that effect the hardness of the case, it's grain structure and defects within the atomic lattice. There's 3 phases in annealing, recovery, recrystalization and grain growth. During recovery, which is what you're doing when keeping temperatures relatively low (750 tempilaq, SBA, etc), enough energy is applied to remove dislocations within the atomic lattice. That moderately softens the case but retains the strength of the cold worked grain structure because there's no recrystalization/grain growth. Heating the case to higher temps (or longer times), causes the grains the recrystalize and grow back as large strain free grains. That's what yields the large reductions in hardness (increase in ductility) but at the expense of a weakened material.
Unfortunately I get up at 2am for work so have to leave it at that but hopefully that gives some insight as to why there's a disconnect between what AMP claims and the experience of users of other annealing methods.
