Annealing color

[UndFrm]

I recently acquired a batch of fired brass (unknown how many times fired), inspected it and went to the annealing step.

Within 2 seconds under the flame, the top gives out a florescent green color on it. This happened to almost 90% brass from the batch. I have inspected for any visual markings and it seems to be fine. The brass is Peterson 284. Would anyone know anything about this bright green color? It goes directly to this color, without passing any red or orange.
I'll try to capture a pic the next time my annealing machine is out.

Thank you

 

[Cynical]

Copper gives off a green/green blue when heated by flame. There’s a majority of copper vs other metals in any brass composition.

 

[RegionRat]

+1 Agree with Cynical.
When I was a young kid and still studying chemistry and metallurgy, copper and cartridge brass burned a green/blue in visible colors.

Also keep in mind, there are always some small surface oxides of the copper, zinc, and contaminates that give off a good show when in a flame.

Don't confuse these flame colors with the heat treat temps. These little chemistry shows in the flame don't mean we know the temperature of the brass.

 

[flogxal]

Yeah for sure what Cynical and RegionRat said. It was an early lesson when I learned CrMo tube brazing with brass fillets. The brass fillet rod introduced to the two-tubes-of-CrMo junction saw the flame go blue to green. Saw it in std inorganic chem labs in HS and college previously, as well.

It's related to the old blue-green haze you can see on old copper pennies sometimes. Copper's natural salt color is that blue-green.

 

[straightshooter1]

I recently acquired a batch of fired brass (unknown how many times fired), inspected it and went to the annealing step.

Within 2 seconds under the flame, the top gives out a florescent green color on it. This happened to almost 90% brass from the batch. I have inspected for any visual markings and it seems to be fine. The brass is Peterson 284. Would anyone know anything about this bright green color? It goes directly to this color, without passing any red or orange.
I'll try to capture a pic the next time my annealing machine is out.

Thank you

You might try cleaning some of those before annealing to see what happens; maybe some residue is causing the brass to burn that color (like maybe the previous owner annealed using a salt bath???).

 

[UndFrm]

Possibly.
I tried using the annealer once again, after a wet tumble and it takes a while to get to that, so will have to adjust the time.

Thank you