overheat brass

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gunbug

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Hi: I think i just ruined my 30-30 brass. I washed the lube off in dish soap&water rinsed and then put in the oven with the door propped open an inch and a half. Cranked the temp control and phone rang. Any way it was on too high {about500F] 1/2 hr later noticed what i did and pulled brass but the old brass instead of brown was almost silver and some of the newer stuff had a bluish green tint. Next time i will make sure oven is on 150 like i usually. Just wanted to let everyone know what happened. Regards
 
Here is a link and some interesting info on annealing: http://www.6mmbr.com/annealing.html


Optimal Case Temperatures for Successful Annealing

Brass is an excellent conductor of heat. A flame applied at any point on a case for a short time will cause the rest of the case to heat very quickly. There are several temperatures at which brass is affected. Also, the time the brass remains at a given temperature will have an effect. Brass which has been "work hardened" (sometimes referred to as "cold worked") is unaffected by temperatures (Fahrenheit) up to 482 degrees (F) regardless of the time it is left at this temperature. At about 495 degrees (F) some changes in grain structure begins to occur, although the brass remains about as hard as before--it would take a laboratory analysis to see the changes that take place at this temperature.


The trick is to heat the neck just to the point where the grain structure becomes sufficiently large enough to give the case a springy property, leaving the body changed but little, and the head of the case virtually unchanged.


If cases are heated to about 600 degrees (F) for one hour, they will be thoroughly annealed--head and body included. That is, they will be ruined. (For a temperature comparison, pure lead melts at 621.3 degrees F).


The critical time and temperature at which the grain structure reforms into something suitable for case necks is 662 degrees (F) for some 15 minutes. A higher temperature, say from 750 to 800 degrees, will do the same job in a few seconds. If brass is allowed to reach temperatures higher than this (regardless of the time), it will be made irretrievably and irrevocably too soft
Click to expand...
 
Never heard of washing brass.
I just fire them back in the tumbler after sizing.
Sounds like a bit of a odd procedure if you ask me.
 
well it's easily remedied with new brass- only about 30 bucks or so for 50 or 100-unless there's a problem with supply- anyway, ive been at this 30+ years and i've never washed or stuck the brass in an oven- just always tumbled- yea, i do know about annealing, but i've never tried it
 
I often wash brass in hot water and automatic dishwasher detergent after sizing to remove case lube. Usually I leave them out to dry for a day before loading.

If I am in a hurry I put them on a cookie sheet for half an hour in the oven set at 200 degrees, let them cool to touch and go. :)

Ted
 
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