Annealing Under the Microscope

[Lapua40X]

Tempilaq

Been there; done that. I have a bottle I'll give you if you want to pay the postage.

 

[Lapua40X]

That is the great thing about the AMP annealer, it is backed up by extensive settings in the library. Most makes of brass and numerous neck thicknesses for neck turned brass are listed. Get on the AMP site and go to the Settings menu and you'll be amazed by the amount of variations covered and the Settings Library is continuously being updated.

Thanks, Willie. I missed that first time around:

(From their web site)

"3. Neck turning does make a difference. As brass is removed, the mass in the air gap reduces, meaning that less power is required. We provide separate settings for standard brass and neck turnings of -0.001”, -0.002” and -0.003”. If requested, we will add settings for further turning reduction. It is important to enter the correct setting. Brass with say 0.003” turned off the neck will be very overheated if the standard setting is used. Our Standard settings now include the nominal neck wall thickness of each cartridge we calibrate. This is an average of six readings per case x 4 cases, using a Mitutoyo tube micrometer with a ball anvil."

http://www.brownells.com/reloading/...aling/induction-case-annealer-prod104413.aspx

 

[memilanuk]

Interesting how this:

1.6 Dezincification

Dezincification is a process where zinc is selectively leached out of the brass leaving behind a weaker copper structure. Dezincification occurs under conditions where certain chemical species such as chloride ions, mildly acidic solutions or ammonia-based chemicals attack the brass. Elevated temperatures can accelerate the dezincification process. On a brass sample, fresh dezincification is evident by a pink-coloured structure and with time this turns darker.

​

I have not seen, experienced or found reference articles that discuss dezincification of brass under heating conditions alone. All avenues point to dezincification in the presence of certain chemicals either on their own or in solutions.​

became this:

Dezincification of brass can occur because of chemical attack, but heating brass, even to high annealing temperatures cannot cause dezincification unless chemicals are present. The zinc content of the alloy cannot burn or melt out up until boiling point (Appendix 1 - 1.6).
​

The whole dezincification thing caught my attention initially because I was under the impression that the orange flame that comes off when the flame is too hot and/or the exposure time is too long, was some portion of the alloy burning off. I'd heard that referred to as dezincification in the past; I can accept that may not be the correct terminology, but if so I'd be interested in what is.

​

 

[Mozella]

....... snip........... I was under the impression that the orange flame that comes off when the flame is too hot and/or the exposure time is too long, was some portion of the alloy burning off. I'd heard that referred to as dezincification in the past;..... snip..........

Dezincification is real and it's potentially dangerous, but only if you put cheap fittings on your boat. Don't worry about your cartridge cases. You won't "burn away" the zinc by annealing cartridge cases.

In basic terms, brass is copper and zinc and bronze is copper and tin or copper and silicon. Zinc is an active metal and when you use brass as a through-hull fitting in a saltwater environment, and especially if you add a little electrolysis like you are bound to get if you plug into shore electrical power, you might very well sink your boat. The zinc leaves the brass and what remains is a pink, spongy, and very weak fitting which can fail in a surprisingly short time. Bronze, on the other hand, contains silicon or tin and electrolysis is much less of a problem.

For those interested in more info, look here:
http://www.proboat.com/2012/07/beware-the-brass/

 

[memilanuk]

You won't "burn away" the zinc by annealing cartridge cases.

Great... so what causes the orange flare I described above, if not burning *something* off?

 

[SheepDog]

The orange flame is caused by contaminants on your brass.

 

[Medic505]

The orange flame is caused by contaminants on your brass.

I totally agree with this statement. I ran a load of brass through a SS pin wash with no soap or lemi Shine and there were no orange flames. Next batch with both and the orange reappeared.

Also this article addresses the removal of carbon in the neck. Looks like I won't be worried so much about that anymore. I see an AMP coming to my reloading room soon.