Annealing Questions

[divingin]

As-in purging? I have pressure coming out, but It is NOT propane. I unscrewed everything and visually check, then blew out with compressed air. I have opened and ran for over 10 minutes, and I am still not getting the propane smell. Could there be that much dead air in each of those tubes???

Well the hole in the torch tip is pretty damn small. When running there isn't all that much flow. Depending on your hose, there could be a significant amount of air in there, but I've never really noticed much of a start up delay. To put it in real perspective, open everything up, allow to pressurize, then shut off everything except the torch valve, and see how long it takes to bleed down. On my setup it's a surprisingly long time.

On the general annealing thing, check out https://www.ampannealing.com/articles/ and look at the "Annealing under the Microscope" series. Though geared towards AMP's products, there is a lot of good info in there.

 

[Straightshooter1]

Well the hole in the torch tip is pretty damn small. When running there isn't all that much flow. Depending on your hose, there could be a significant amount of air in there, but I've never really noticed much of a start up delay. To put it in real perspective, open everything up, allow to pressurize, then shut off everything except the torch valve, and see how long it takes to bleed down. On my setup it's a surprisingly long time.

On the general annealing thing, check out https://www.ampannealing.com/articles/ and look at the "Annealing under the Microscope" series. Though geared towards AMP's products, there is a lot of good info in there.

Yes, that Annealing Under The Microscope series is a really good read. I only wish they had collected data on flame annealing instead of salt bath annealing for a comparison.

 

[Tesoro]

I can see Prairie Doggers and PRS guys needing machines to anneal bulk brass, but thats not me who will shoot 50 rounds per range session per rifle. I sold my machine because I was annealing for at least 4 diff cartridges and the initial set up for each size was too much of a pita to do 50 or 100 cases.
I came up with my own invention using a mini potters wheel where all I have to do is light the torch and 20 minutes later I have done my 100 of any size. KISS

 

[BHP9]

I can see Prairie Doggers and PRS guys needing machines to anneal bulk brass, but thats not me who will shoot 50 rounds per range session per rifle. I sold my machine because I was annealing for at least 4 diff cartridges and the initial set up for each size was too much of a pita to do 50 or 100 cases.
I came up with my own invention using a mini potters wheel where all I have to do is light the torch and 20 minutes later I have done my 100 of any size. KISS

View attachment 1748960

Well, that's inventive! well done.

 

[fatelvis]

I know a lot of you guys are saying that "flash heating" your brass at 750* does next to nothing to anneal, but I have been doing just that for about four years now on every firing, and I see a marked improvement in the shoulder bumping consistency over non-annealed brass. It obviously is doing something beneficial towards sizing consistency. Just my observation.

 

[Webster]

I know a lot of you guys are saying that "flash heating" your brass at 750* does next to nothing to anneal, but I have been doing just that for about four years now on every firing, and I see a marked improvement in the shoulder bumping consistency over non-annealed brass. It obviously is doing something beneficial towards sizing consistency. Just my observation.

Your probably stress relieving. It would be interestting if stress rellieving reduces or prevents neck cracks. I reloaded from 1970 to about 2005 without annealing. I don't remember tossing much brass from neck cracks. . Didn't know anything about shoulder bump in that time period. I still killed a lot of ground hogs. I doubt that most of us shoot good enough to see the difference in good shoulder bump and a large variation. I use a 6BR and a 6BRX for GH hunting with Kreiger barrels and Lapua brass. More than good enough for varmints. Both rifles can shoot under .350" with good bullets.

If your happy with 750F keep doing it. Case life was all I wanted from annealing, not an accuracy improvement.

 

[kelbro]

I know a lot of you guys are saying that "flash heating" your brass at 750* does next to nothing to anneal, but I have been doing just that for about four years now on every firing, and I see a marked improvement in the shoulder bumping consistency over non-annealed brass. It obviously is doing something beneficial towards sizing consistency. Just my observation.

It has been my understanding that the correct terminology for what we are doing is stress relieving.

 

[Webster]

It has been my understanding that the correct terminology for what we are doing is stress relieving.

Stess relieving should do little if anything to make the brass softer. Annealng makes the brass softer.

 

[kelbro]

Stess relieving should do little if anything to make the brass softer. Annealng makes the brass softer.

It bends easier. It does not seem to trim any easier. I can tell that it's softer so it's possible that I am annealing. A metallurgist once corrected me and the term 'stress relieving' stuck in my head.

I get great sizing and have not seen a split neck after many reloads so I will continue doing whatever this is.

 

[Webster]

It bends easier. It does not seem to trim any easier. I can tell that it's softer so it's possible that I am annealing. A metallurgist once corrected me and the term 'stress relieving' stuck in my head.

I get great sizing and have not seen a split neck after many reloads so I will continue doing whatever this is.

The report doesn't have much value to compare to flash annealing. Probably not worth looking at.

Reading the report may be boring. I tend to just look at the text charts. and graphs. Not flash annealing. The charts are a one hour anneal. I tend to just get an idea of whats going on. I try to compare 1 hour to flash anneal at 750F.

A college thesis on stress relieving 70/30 brass. A good read.

The properties of cold rolled - stress relief annealed 70-30 cartridge brass

"Because of the possible commercial application of the proposed treatment of 70-30 brass, this work was undertaken. In addition, the data resulting from this work will result in a better understanding of the treatment of brass. The objectives of this work were as follows: Determine if higher...

scholarsmine.mst.edu

 

[Straightshooter1]

Here another college thesis on Recrystallization on Behavior of 70/30 brass:

Recrystallization Behavior of 70/30 Brass

Cartridge brass undergoes significant changes in mechanical properties as a result of cold work. These changes are effectively reversed in the annealing process returning the metal to its precold-worked state. The major goal of this study is to

www.academia.edu

And other newer one from year 2014 Characterisation Study of Brass Cartridges for High End Competition Target Shooting (note the Tempilaq temperature on page 23 ):

https://ballisticrecreations.ca/wp-content/uploads/2019/06/Ryan-Stevenson-Dissertation.pdf

 

[Webster]

Here another college thesis on Recrystallization on Behavior of 70/30 brass:

Recrystallization Behavior of 70/30 Brass

Cartridge brass undergoes significant changes in mechanical properties as a result of cold work. These changes are effectively reversed in the annealing process returning the metal to its precold-worked state. The major goal of this study is to

www.academia.edu

And other newer one from year 2014 Characterisation Study of Brass Cartridges for High End Competition Target Shooting (note the Tempilaq temperature on page 23 ):

https://ballisticrecreations.ca/wp-content/uploads/2019/06/Ryan-Stevenson-Dissertation.pdf

Very good article. I need to spend some time reading it. The first time I heard that expansion of the neck from firing produced more hardness increase than sizing. Industry sometimes uses whats called explosive forming. They lay a piece of metal on a die, place a sheet of high explosive on top and set it off. A whole new interpretation of metallurgy.

 

[Tesoro]

And other newer one from year 2014 Characterisation Study of Brass Cartridges for High End Competition Target Shooting (note the Tempilaq temperature on page 23 ):

https://ballisticrecreations.ca/wp-content/uploads/2019/06/Ryan-Stevenson-Dissertation.pdf

Well there ya go!!! ^^^^^

So much for hand annealing to improve accuracy! For extending case life anneal every time or dont do it at all. For precision competition use virgin brass, with choice to neck turn or skim. Don't turn necks all the way to the junction.

Hand annealing necks to even out neck tension on multi use cases is a myth, unless it is possibly done with a more controlled method such as a timed induction annealer. Similar testing would have to be done to prove how it affects the brass structure.

I have always been a believer that there are many other variables that will overcome the benefit of annealing for the purpose of getting more consistent neck tension. For one, just think about the variable amounts of lube we put on each bullet.

I can make up the best batch of used brass I can, and when seating with my arbor press I wind up having 3 batches separated by the feel of the seating pressure. With new brass I get 2 batches.

I try to set neck tension at max 1 thou because I believe the lesser the tension the lesser the effect of uneven neck brass. But what do I know. Long term amateur!

I am going to look into an induction annealer!

 

[Straightshooter1]

Very good article. I need to spend some time reading it. The first time I heard that expansion of the neck from firing produced more hardness increase than sizing.

Being curious about how much a firing of a cartridge hardened the neck, when I took measurements before and after a single firing, I found little change, if any could be discerned at all. It was the sizing process that had significant affect on hardening the necks vs what the pressure does. Of course, the amount of movement going on in the whole cycle is a big factor.

Industry sometimes uses whats called explosive forming. They lay a piece of metal on a die, place a sheet of high explosive on top and set it off. A whole new interpretation of metallurgy.

I've seen a couple reports on "explosive forming", once on an episode of Myth Busters and another about an artist producing his art in that manner. It was fascilnating to me seeing how that works and how it can be controlled to some exent.