Annealing till glow or 750??

[Randy L]

I KNOW my method works

What is your method? Thanks in advance.

Randy

 

[Webster]

We all know that brass differs in thickness and composition. Variances between manufacturers are well documented. Even something as “simple” as differing lot numbers of the same brand can show variance. How can 750 degrees be a hard and fast rule?

I don't see how carbon, 2 thou neck thickness variation or % zinc can have much affect on the time to reach temperature. Copper is a very good conductor of heat. I agree with several others 750F is probably stress relieving not annealing. A fraction of a second at 750F will not change the brass hardness.

 

[Fotheringill]

I choose to use the 750 Tempilaq method. Having made that decision, I stick with.

All the second guessing can drive you nuts, particularly in a hobby that draws anal retentive types like shit draws flies (and I put myself squarely in that group)

Indeed.

 

[muleman69]

I have been working with metals for most of my life. I trust my eyes and the color of the metal. I bring it up to a dull to medium red which should be about 800-1000 degrees. I anneal every firing to ensure consistent neck tension and to relieve stress in the metal. I have gotten up to 22 firings out of my Lapua .308 Win brass so far and still counting.
I am not concerned with excessive heat as I would have to get it much hotter to start bringing out the zinc in the metal.
As far as I am concerned, if you don't get the red then you aren't doing anything but warming up the metal.
Just my $0.0002 worth.

Can't beat true results, good enough for the girls I go with

 

[MagnumManiac]

What is your method? Thanks in advance.

Randy

My annealer is self fabricated using a rotating table, solid steel top with holes for the cases to sit in atop a solid disc with a slot milled in for the cases to fall out into a basket. I use 3 torch heads/angles and the cases rotate for 6-8 seconds in the flame.
The dwell time is controlled by essentially a speed controller for other electrical applications.
I can adjust the speed of the spin of the table, the cases rotation and time in the flame.
I copied an existing commercial design but used my own electronics and heat/flame system.

Cheers.

 

[Ccrider]

It looks like the salt bath method is easieer to regulate and more precise than torches. A lots cheaper than an Amp too.

 

[Webster]

So I have an annealeez. I also have 750 tempilaq. With the cheap hornady brass I have, if I turn the lights out the brass gets the deep glow right at 750 degrees. Perfect. Then when I do the lapua brass I turned to the same neck thickness to the hornady and run it through the annealer I see no glow when the tempilaq disappears at 750. Even if I slow down the speed a lot, way past the 750 mark, I still don’t see a glo. What the heck. I do not want to super over anneal the brass and ruin it. Thoughts please

Tempilaq is not intended to be used with a 1800F flame on it. I used Tempil Stiks a lot at work. We took a hot piece of steel plate from a hot rolling mill and rubbed the Tempil Stik on it. Templaq and Tempil Stik are intended to be used on a hot surface, not with external heat being applied while testing. Should be OK in an induction annealer because the metal is heated from the inside. With a flame it should be inside the neck so you don't have direct contact with a 1800F+ flame. If you pay attention it's difficult to over anneal. Rapid hardness change starts to occur when the brass glows red for more than a couple seconds.

 

[Dusty Stevens]

Tempilaq is not intended to be used with a 1800F flame on it. I used Tempil Stiks a lot at work. We took a hot piece of steel plate from a hot rolling mill and rubbed the Tempil Stik on it. Templaq and Tempil Stik are intended to be used on a hot surface, not with external heat being applied while testing. Should be OK in an induction annealer because the metal is heated from the inside. With a flame it should be inside the neck so you don't have direct contact with a 1800F+ flame. If you pay attention it's difficult to over anneal. Rapid hardness change starts to occur when the brass glows red for more than a couple seconds.

Everybody ive seen does put the tempilaq inside the neck

 

[bigfish28]

The answer is in the Copper-Zinc phase diagrams. Annealing is to set a specific crystalline structure. The phases diagrams I looked at (on the Internet) it appears the structure desired is Beta. If this is true ( I am not a brass metallurgy person) this can be achieved by heating to over 800 degrees F.
This what I work for 750 to 800 window for best annealing. There is to much variance in many parts of this. It would be great if a metallurgist posted.

 

[riflewoman]

Here is a phase diagram from the Copper Development Association. It has % Zinc on the horizontal scale and temperature on the vertical scale. Cartridge brass is 70% Copper and 30% Zinc. If you go vertically (increasing temperature) there’s no way you can get any Beta alloy as the metal will melt first. Note that the temperature on the right is in Fahrenheit. So it melts at about 1700F.

Look under my postings on many threads for links to published papers on annealing. These indicate that unless you get to at least 1000F you’re only stress relieving not annealing.

Not a metallurgist, but a mechanical engineer for 30+ years...

 

[muleman69]

Tempilaq is not intended to be used with a 1800F flame on it. I used Tempil Stiks a lot at work. We took a hot piece of steel plate from a hot rolling mill and rubbed the Tempil Stik on it. Templaq and Tempil Stik are intended to be used on a hot surface, not with external heat being applied while testing. Should be OK in an induction annealer because the metal is heated from the inside. With a flame it should be inside the neck so you don't have direct contact with a 1800F+ flame. If you pay attention it's difficult to over anneal. Rapid hardness change starts to occur when the brass glows red for more than a couple seconds.

You have mentioned it is difficult to over anneal ,so if I put tempil inside the neck and wait for it to melt I should be okay even if the neck glows a bit?

 

[dcali]

The answer is in the Copper-Zinc phase diagrams. Annealing is to set a specific crystalline structure. The phases diagrams I looked at (on the Internet) it appears the structure desired is Beta. If this is true ( I am not a brass metallurgy person) this can be achieved by heating to over 800 degrees F.
This what I work for 750 to 800 window for best annealing. There is to much variance in many parts of this. It would be great if a metallurgist posted.

Brass isn’t like steel- you’re not changing crystal structures, you’re just shrinking/growing the grains. The hotter it gets the faster it happens. Most references quote 1 hour temperatures, which will be lower than what is required for our purposes. How much lower is a matter of debate unless you’ve got access to some pretty fancy equipment. It’s really hard to measure in short periods of time.

 

[TC260]

View attachment 1079111Look under my postings on many threads for links to published papers on annealing. These indicate that unless you get to at least 1000F you’re only stress relieving not annealing.

Not a metallurgist, but a mechanical engineer for 30+ years...

Mechanical engineer here too. The materials professors and textbooks I had in school refered to it as partial or recovery annealing because it's annealing that's limited to the recovery phase. Reorienting the atomic lattice without change to the grain structure.

 

[riflewoman]

Mechanical engineer here too. The materials professors and textbooks I had in school refered to it as partial or recovery annealing because it's annealing that's limited to the recovery phase. Reorienting the atomic lattice without change to the grain structure.

The term the metals guys use now is “Sub-critical Annealing”. Keeps the benefits of the cold work without the residual stress...at least that’s the theory.

 

[TC260]

Well at least the brass still behaves the same regardless of what they call it

 

[hambone1971]

Maybe stress relieving brass is all we need to do to make it last. Seems to work for me.

 

[Webster]

View attachment 1079111

Here is a phase diagram from the Copper Development Association. It has % Zinc on the horizontal scale and temperature on the vertical scale. Cartridge brass is 70% Copper and 30% Zinc. If you go vertically (increasing temperature) there’s no way you can get any Beta alloy as the metal will melt first. Note that the temperature on the right is in Fahrenheit. So it melts at about 1700F.

Look under my postings on many threads for links to published papers on annealing. These indicate that unless you get to at least 1000F you’re only stress relieving not annealing.

Not a metallurgist, but a mechanical engineer for 30+ years...

If I remember from 30 years ago these phase diagrams are for temp and % Zn and phases for an infinite time. Agree only alpha phase possible. The chart doesn't apply to annealing.

 

[Webster]

You have mentioned it is difficult to over anneal ,so if I put tempil inside the neck and wait for it to melt I should be okay even if the neck glows a bit?

If your removing heat when the Tempilaq melts at 750F how could it glow red. Red is about 1050F?

 

[Martin52]

fwiw, using the drill and socket method with a single propane torch on 308 lapua cases with 0.014 neck thickness, I get a dull to medium red at about the 7 second mark, the 450 Tempilaq on the case body is then melting about 1/3 way down from case body/shoulder junction.

 

[muleman69]

If your removing heat when the Tempilaq melts at 750F how could it glow red. Red is about 1050F?

Bit confused ? Should I go 750 or red?