June 27th, 2018

Accidental Annealing — Did Your Wife Kill Your Brass?

Oven anneal annealing Alpha Munitions Craig Arnzen Area419.com
NOTE: If you prefer drying your brass in an oven we recommend a temp setting no higher than 200° F. Better yet, use a dedicated case dryer that cannot possibly over-cook your cases.

Tech Tip by Craig Arnzen of Area419.com
As wet-tumbling brass has become more popular in recent years, guys have tried a LOT of ways to get their brass dry — towels, hair dryers, and even food dehydrators. (See Top Ten Brass Drying Methods). Another common method — albeit with some potential issues — is putting your wet brass in the oven to dry. Provided you monitor TEMP and TIME, this method is fast, effective, and easy (as long don’t use the wife’s favorite cooking pans — that’ll get you in trouble.)

With oven-drying, however, unexpected issues can arise, as illustrated by this worrisome story: “I put my brass in for an hour at 200° F and turned it off. Next thing I know I realize my wife has the oven pre-heating to 350° F. Is my brass ruined?”

Oven anneal annealing Alpha Munitions Craig Arnzen Area419.comIf you search the AccurateShooter.com Shooters’ Forum, you’ll find at least three threads with stories like that (i.e. higher-than-expected oven temps when drying brass), and answers on both sides of the line. I know this, because it happened to me — I had some 6XC brass drying and the wife pre-heated the oven. Concerned about my cases, I consulted a genuine annealing expert, Andrew Rixon.

Andrew is the Director of Engineering and Manufacturing at Alpha Munitions, makers of premium-grade rifle brass. I had baked a batch of Alpha’s new 6XC brass, which is exceptionally consistent and well-made.

Before Andrew would answer my question though, he gave me a little lesson on what really happens during annealing:

“Annealing is performed by heating the brass to specific temperatures. There are three phases of annealing: recovery, recrystallization, and grain growth. All of which have specific temperatures and or exposure times related to them. It is key for cartridge brass annealing processes to hit the recrystallization phase which allows for strain-free grains to grow. The growth of strain-free grains eliminate dislocations, drastically decreasing hardness and increasing ductility. For recrystallization to occur the material temperature must be within 600-1000 degrees Fahrenheit (F).”

Oven anneal annealing Alpha Munitions Craig Arnzen Area419.com

He then got into really answering the question, and was (fortunately) definitive in his answer: “If the temps do not exceed 450 degrees F then there is nothing to worry about as it did not exceed the critical temperature for annealing to occur.” Editor: Caution — do NOT assume that the temperature marked on the oven knob is the actual temperature INSIDE the oven, particularly near the back. Some older ovens can be off as much as 75 degrees F. Be conservative!

Well, there you have it. If you’ve baked your brass, you’re probably OK. If you got it hotter than 450° F then there can start to be some changes to the metal, but we will let you learn more about that directly from Andrew, who is working on a lengthy, detailed article on the science of annealing, to be released later this summer.

This TECH TIP brought to you by Area 419
Oven anneal annealing Alpha Munitions Craig Arnzen Area419.com

Want to learn more about Alpha Munitions? Visit AlphaMunitions.com.