Hydraulic case forming

Started by Newton, Apr 22, 2023, 10:31 PM

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oafpatroll

Happily none of my dreams were harmed by your post. A few of my nightmares may have been confirmed though ;)



JamesNotBond

Quote from: oafpatroll on May 03, 2023, 11:19 AMHappily none of my dreams were harmed by your post. A few of my nightmares may have been confirmed though ;)
Perhaps ?
https://youtu.be/a01QQZyl-_I?t=64

Newton

Quote from: Brian on May 02, 2023, 10:28 PMI worked in hydraulics and pneumatics all my life. Owned my own medium sized hydraulic and pneumatic company for over 30 years.
Thanks
Unfortunately no-one has yet clarified just EXACTLY how much pressure is needed to "form" brass a few thou mm
I can "form" brass using case lube in my LEE Challenger press - 300 Win Mag to 308 Norma Mag
Which involves relocating the neck and shoulder
However that is not going to help if you need to "blow-out" all the case dimensions ... a few thou mm

Before we - speculate can someone give a properly calculated answer as to exactly how much pressure is required to do this ?
I would suggest it is far BELOW the crazy pressures mentioned here ....


janfred

https://www.azom.com/article.aspx?ArticleID=6341

Print it out and ask your workshop buddy to interpret.

The property you are looking for is called "yield strength". Also known as the elastic limit. That depends on the temper of the brass.

Cartridge makers like Norma and Lapua manipulate the temper of the brass they use to get as close to full-hardness at the webb and and around 1/4 temper at the neck and shoulder. Kan be as soft as 20 ksi for the neck to 65 ksi at the web area. The softer the material the less springback you get and the more difficult it becomes to extract.

There is a reason why rifle calibers are all below 65 ksi pressure rated.

223

Quote from: Newton on Apr 22, 2023, 10:31 PMGreetings
I am sure most people know about hydraulic case forming using a special die and water to form cartridge cases
Rather than the normal fire-forming which uses expensive components.
The hydraulic method can however potentially be a bit messy

I wonder if anyone has looked at using a - Pneumatic process to do the same work ?
Would be a lot cleaner and not messy
Should not be too difficult to make the necessary parts ?
I do wonder what kind of air pressure you would need though ?
300 Bar is not unusual in some engineering processes.

The components used for fire forming are only expensive if you waste them.

My idea of fire forming, barrel break-in etc is to make a useful load and actually do something useful while doing these operations.  There is no reason a fire-form load can not be used on a target or even a varmint or game animal in the field.

Newton

Quote from: 223 on May 07, 2023, 10:12 PMThe components used for fire forming are only expensive if you waste them.

My idea of fire forming, barrel break-in etc is to make a useful load and actually do something useful while doing these operations.  There is no reason a fire-form load can not be used on a target or even a varmint or game animal in the field.
It would be interesting to take twenty good factory rounds and put them on target at 100m - with a chronograph
Then take twenty rounds to be fire formed and do the same ( of course it depends on what it is you are trying to fire-form )

I wonder what you would see / learn ?

IF in the US ( and wealthy ) this is what you do ...





Newton

Quote from: janfred on May 07, 2023, 08:42 PMhttps://www.azom.com/article.aspx?ArticleID=6341

Print it out and ask your workshop buddy to interpret.

The property you are looking for is called "yield strength". Also known as the elastic limit. That depends on the temper of the brass.

Cartridge makers like Norma and Lapua manipulate the temper of the brass they use to get as close to full-hardness at the webb and and around 1/4 temper at the neck and shoulder. Kan be as soft as 20 ksi for the neck to 65 ksi at the web area. The softer the material the less springback you get and the more difficult it becomes to extract.

There is a reason why rifle calibers are all below 65 ksi pressure rated.
Thanks
Did you check and measure your brass at the web ?
Before firing / after firing / after reloading
Did you check and measure you FL sizing die ?

IS there any movement at the web ?

I would suggest that this is a rough method that some use to check for pressure signs

I am interested to know -  IF this area is sized at all in the FL sizing process ?

IF so how much pressure you are exerting with your reloading press - 65ksi ?


Newton

Quote from: janfred on May 07, 2023, 08:42 PMhttps://www.azom.com/article.aspx?ArticleID=6341

Print it out and ask your workshop buddy to interpret.

The property you are looking for is called "yield strength". Also known as the elastic limit. That depends on the temper of the brass.

I see this also explained here ...

The Truth of the Myth


Newton

I have now discovered that the pressure needed to fire-form brass is 12,000.00 psi
According to the MS calculator = 827.37084 BAR
Still a lot ...

janfred

Please share with us your calculations or source