Thread: Cooked my brass, Whoops

I forgot about my brass I put in the oven to dry after tumbling. Looks like I annealed the whole batch.
180 degrees for 30 minutes, I was meant to lightly warm the oven then turn off leaving the fan going. Bloody TV distracted me.

Would you still use it?

I am not a metallurgical whizz but no I personally wouldn't use it.

50°-100° is all you need but for a bit longer.
Dehydrator if ya have one works better.

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Yeah thanks, I thought the same.
I've binned them.

In theory though you should be alright. The temperature at which strength begins to be affected in brass is close to 240 celcius according to the chart below. Despite this I'm inclined to agree with R93 and err on the side of caution.

I too would err on the side of caution, but it would be interesting to do the crush test with pliers to see how much softer they are than virgin brass.

Where'd you get that graph from @Puffin ?

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Originally Posted by Feather or Shoot

Where'd you get that graph from @Puffin ?

Hmmm... tricky to recall now, but my best guess would be that I copied it from a posting by The Firing Line & Shooters' Forum stalwart Unclenick. It appears to be taken from a metallurgy text.

@Feather or Shoot I recently came across the following:
http://web.nchu.edu.tw/~jillc/me/Ch1...0Treatment.pdf
Pages 33-37

Originally Posted by Puffin

@Feather or Shoot I recently came across the following:
http://web.nchu.edu.tw/~jillc/me/Ch1...0Treatment.pdf
Pages 33-37

That's some confusing stuff @Puffin!

I get that softening happens during the re crystallization temperature boundaries of 200& 500°C. I don't get how they don't show time on that graph. They then refer to the annealing of brass at 580°C being totally re crystallized after 8 seconds.
Interesting that the more worked brass is the less temperature it takes to anneal.

In the steel section they talk of age hardening at low temperatures for long times, I wonder if brass age softens when treated the same.

Any idea what hardness we are aiming for when annealing cartridge brass?

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Originally Posted by Feather or Shoot

That's some confusing stuff @Puffin!

I get that softening happens during the re crystallization temperature boundaries of 200& 500°C. I don't get how they don't show time on that graph. They then refer to the annealing of brass at 580°C being totally re crystallized after 8 seconds.
Interesting that the more worked brass is the less temperature it takes to anneal.

In the steel section they talk of age hardening at low temperatures for long times, I wonder if brass age softens when treated the same.

Any idea what hardness we are aiming for when annealing cartridge brass?

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Agree. I'm assuming that time is fixed, but no figure has been given, and then the crossing of the data plots in figure 10-33 is unintuitive. Also online searches reveal a differing in opinion over whether low temperature "age" annealing is possible. If I was sufficiently motivated I'd spend a day up at the VUW library trying to get to the bottom of it as it is in the area of my educational background, but my DIY inductive annealer has recently appeared to result in a halving of vertical dispersion out to 1000 metres so I'm content at the moment to engage in casual reading on the topic, follow the debate in an ill-informed manner, while enjoying the practical benefits !

Originally Posted by Puffin

Agree. I'm assuming that time is fixed, but no figure has been given, and then the crossing of the data plots in figure 10-33 is unintuitive. Also online searches reveal a differing in opinion over whether low temperature "age" annealing is possible. If I was sufficiently motivated I'd spend a day up at the VUW library trying to get to the bottom of it as it is in the area of my educational background, but my DIY inductive annealer has recently appeared to result in a halving of vertical dispersion out to 1000 metres so I'm content at the moment to engage in casual reading on the topic, follow the debate in an ill-informed manner, while enjoying the practical benefits !

Always wanted to do a DIY induction annealer. Where'd you get the parts and plan from? Or is this original puffin magic?

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Is that a graph? Looks like a drawing from my 2 yo

Id use em, well below annealing temp.

I park em for 30 mins at 100 degrees C (with the timer on) cos I'm a dumb shit and bound to forget and miss the timer. Worst case is I just have very very dry brass. Then, once timer goes, I just switch the oven off and crack the door for half an hour to let them cool.

If you look at that graph it says it's for one hour. I'm guessing if you left the brass hot for ages the temperature required to anneal would be less.

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From what I've read that isn't the case. Annealing doesn't start at all until a particular temperature is reached. Then it proceeds very quickly. Is that right? I'm no expert.