Salt Bath Annealed Necks collapse during seating

[jthor]

Though the biggest problem here is you sized and then annealed. Annealing will deform the brass which is why you want to anneal then resize. So your problem isn’t from SBA flash annealing too soft, which it cannot, it’s your Brass was deformed during the seating operation.

 

[Texas10]

Though the biggest problem here is you sized and then annealed. Annealing will deform the brass which is why you want to anneal then resize. So your problem isn’t from SBA flash annealing too soft, which it cannot, it’s your Brass was deformed during the seating operation.

What deformation are your referring to? I haven't been able to measure any deformation before, so if you know where to look, please don't hesitate to school me on what you've observed. Inquiring minds would like to know.

 

[mikecr]

1,000°F is a bit higher than needed. I agree with the recommended 850°F.
But it takes ~1200°F to begin full annealing, and I would be surprised if that could be reached with a LEE pot and salt, even set at max.
Mine wouldn't(with lead).

From the people bringing SBA to us:
NOTE: If heated above 590°C [1094°F] this salt will begin to decompose, releasing hazardous nitrogen oxide fumes . At higher temperatures the salt becomes a powerful oxidizer that may cause spontaneous and violent ignition of flammable materials,,

A fuming hazard applies with pure lead, with ~similar excess temperatures.
It's simple: just don't go out of your way to mess up here.

 

[Texas10]

I think I accidentally had my Lee melter pot up to 1125 F one SBA session when I got distracted and let mine go a little too long before rechecking. Brass didn't seem to mind, nor did my lungs so maybe the hazards are a bit overblown.

I've read a lot of testing regarding re-crystalization, grain structure, Hardness, but never any testing where a measurement of force required to expand or yield the neck without the friction element seen when seating a bullet. I think that would be a more useful measure of anneal effectiveness.

 

[jthor]

What deformation are your referring to? I haven't been able to measure any deformation before, so if you know where to look, please don't hesitate to school me on what you've observed. Inquiring minds would like to know.

Umm I have no way of measuring. If you go look through legitimate articles on annealing brass you’ll find in some of them they discuss the deformation that happens in annealing. Lapua even mentions it on their website. Deformation after heating is typical in a lot of metals. Even in steel, there’s a reason why you do not heat treat to relieve stress in the metal after rifling, it will warp slightly. While brass does not act like steel, especially in the area of tempering and annealing, it deforms during heat treatments.

 

[Rick300]

I use a metronome app on my phone to time it. Works great. Also have done 1000 degrees for 6 seconds with no ill effects.

 

[mikecr]

I've read a lot of testing regarding re-crystalization, grain structure, Hardness, but never any testing where a measurement of force required to expand or yield the neck without the friction element seen when seating a bullet. I think that would be a more useful measure of anneal effectiveness.

Unfortunately, nothing currently exists to do this.

 

[jthor]

^ AMP currently is working on something that some what fills that roll. Works for seating. No news if they will end up producing the unit, but they might if there is enough interest. Still in the RnD phase currently.

 

[riflewoman]

Two words for simple thermodynamics, heat transfer. The rate at which the brass heats is faster when the delta in temperature between the brass and the heat source is large. Once that delta becomes smaller the rate at which the brass heats up becomes slower. Furthermore, just because you put something in a hot liquid for 6 seconds does not mean, at all, that it has reached the temperature of the liquid.

While the mechanism of heat transfer here is complex as there is both conduction and convention, I would submit that the primary transfer method here is conduction. And you have a few grams of brass in intimate contact with tens if not hundreds of grams of molten salt. The brass gets to temperature pretty quickly.

 

[jthor]

While the mechanism of heat transfer here is complex as there is both conduction and convention, I would submit that the primary transfer method here is conduction. And you have a few grams of brass in intimate contact with tens if not hundreds of grams of molten salt. The brass gets to temperature pretty quickly.

Not as quickly with bottleneck cases due to variable surface area and the body itself acting as a heat sink with SBA. Straight walled cases do anneal better with SBA than bottlenecked cases do. I really do not want to debate this here though. Lol

 

[dolek]

Umm I have no way of measuring. If you go look through legitimate articles on annealing brass you’ll find in some of them they discuss the deformation that happens in annealing. Lapua even mentions it on their website. Deformation after heating is typical in a lot of metals. Even in steel, there’s a reason why you do not heat treat to relieve stress in the metal after rifling, it will warp slightly. While brass does not act like steel, especially in the area of tempering and annealing, it deforms during heat treatments.

I am with you on this 100 percent . Brass will deform slightly while annealing.

 

[Straightshooter1]

Umm I have no way of measuring. If you go look through legitimate articles on annealing brass you’ll find in some of them they discuss the deformation that happens in annealing. Lapua even mentions it on their website. Deformation after heating is typical in a lot of metals. Even in steel, there’s a reason why you do not heat treat to relieve stress in the metal after rifling, it will warp slightly. While brass does not act like steel, especially in the area of tempering and annealing, it deforms during heat treatments.

Hmmm??? All the more reason to do annealing as the very first operation after firing. huh?

 

[mikecr]

^ AMP currently is working on something that some what fills that roll. Works for seating.

We already have that, at probably 1/4 of what they'll charge. It's not what we need to measure actual hoop tension.

 

[jthor]

Hmmm??? All the more reason to do annealing as the very first operation after firing. huh?

I prefer to deprime, clean and then anneal, but that’s just me.

 

[jthor]

We already have that, at probably 1/4 of what they'll charge. It's not what we need to measure actual hoop tension.

No one has something like this that records the force on the press and graphs it. In the graph the lines on the bottom are annealed cases and the ones on top are not annealed.

 

[mikecr]

There are at least 3 or 4 existing seating force systems on the market. Graphing has been done in the past as well: https://www.shootingsoftware.com/recoil.htm
I have sampling modules and have graphed seating forces in the past, but there is no value in graphing over direct readout for this.

Anyway, we currently have no method of directly measuring neck tension.
You can lap up AMP kool-aid if you like, but all seating forces have shown us directly is seating friction.
That's not to say it isn't useful information(potentially), but only if you understand what you're actually doing & seeing.
To begin, you have to understand that push/pull forces are not neck tension. Most folks can't get past that much, and I doubt AMP will either.. The OP did not collapse shoulders due to 'high neck tension', regardless of the forces that could have been sensed/graphed with his efforts.

 

[Uncle Ed]

You do not need a salt bath annealing system to collapse the case shoulder.

All you need to do is set the seating die to crimp the case mouth before the bullet is fully seated.

You can argue if neck tension, bullet grip, friction or too much gravity causes this. I threw my 30-30 case with the collapsed shoulder in the trash, readjusted the die and didn't let anyone know I screwed up.

P.S. Sorry mikecr if I caused any "friction" between us with this post. I also have a question for you mikecr, if you rub two bullets together can you start a fire and burn down a forum?

And does anyone mind if I dunk.

 

[DDRH65PRC]

You do not need a salt bath annealing system to collapse the case shoulder.

All you need to do is set the seating die to crimp the case mouth before the bullet is fully seated.

You can argue if neck tension, bullet grip, friction or too much gravity causes this. I threw my 30-30 case with the collapsed shoulder in the trash, readjusted the die and didn't let anyone know I screwed up.

P.S. Sorry mikecr if I caused any "friction" between us with this post. I also have a question for you mikecr, if you rub two bullets together can you start a fire and burn down a forum?

And does anyone mind if I dunk.

Dry lube media like above will help. Also, dry tumbling brass will help too. Wet brass cleaning will cause friction between the brass and copper jacket. Metal on metal. Seating bullets will feel like high neck tension. Dry lube and/or dry tumbling will add a layer of leftover carbon for the bullet to seat smoothly.

 

[Pawnee Bill]

probably annealed too long ...

That's my guess.

 

[Texas10]

About 5 seconds at 1000 F is too long? If so, how is 3300 F for 3 or 4 seconds better? If you have any data to support that, I'd be very interested in reading. Inquiring minds would like to know.