Bump Heat treatment of cast bullets
quote:
Jim Stark
QUESTION????? If you quench a cast bullet(s) right out of the mold... and this hardens the surface...What happens to that hardened surface when you run them thru the sizer????
Thanks,
JIM..............
Part 1
Alloy has everything to do with shrinkage percentage. When you cast a bullet that has been overly sized, it will remove the layer of hardness induced by the quenching. The entire bullet is not = in hardness in the through sectional, therefore you have to pay attention to alloy and the resulting dimensions. The closer you have to final size from the mold, the more you retain the hardness layer.
If you want more hardness, increase antimony to 6%, if you want less, drop it to 2%. An increase in antimony decreases the time required to exit the lower side of the transformation range, which in turn increases the hardness.
You can also add trace levels of arsenic (1/4% of 1% or so) and this will also increase the effect of hardening/and depth of hardening through quenching. 1/2 to 3/4 of 1% will get you into the brittle range where it will shatter when it hits steel with sufficient velocity. (all predicated on .5% max or less tin, 5-6% antimony, and remainder lead)
Part 2
quote:
dandak1
Don, your link has an answer in it...the fellow at LASC tested 10 year old heat treated bullets and found they had only softened a little. That was what I needed to know. I can go ahead and load up 200 or so rounds and if it takes me a year or so to go thru them they will still be as hard as when I cast them. I also learned NOT to skim off the antimony from the top of the melt (I had been doing that but didnt know it was antimony). That article was excellent. Thanks again.
quote:
Jim Stark, read the lasc article, he answers your question, basically running them thru a sizer can work soften them. I dont size my bullets so I didnt pay much attention here, but believe he says to size them before he oven treats them. If you water quench like I do, well, sizing may work soften the surface which is probably not what you want.
Plan on (finally) having some time to myself this weekend, where I will read the other links that readers have been kind enough to post. Thanks guys.
There is no such thing as work softening for metals in the context that is stated here. A standard stress strain diagram will show that it first passes through the elastic range (range at which it will return to it's original shape if bent AKA yield strength) then it will hit the plastic range (range at which a metal does not return to it's original shape but no exactly in the work hardening stage yet. The peak of which is known as its ultimate yield strength and the lead up to it being known as it's strain hardening region) Then it gets to the work hardening stage at which it becomes brittle and starts necking down and eventually snaps (brittle fracture).
http://www.optics.arizona.edu/optomech/references/OPTI_222/OPTI_222_W4.pdf
A good basic article on metallurgy designed to clue in optical engineers
http://en.wikipedia.org/wiki/Tensile_strength
More of a lay person explanation but still mostly accurate.
Here is a video I have from a tensile test of a weld sample.
http://s128.photobucket.com/albums/p190/CWI555/?action=view?t=tensile.flv
At 26 on the time line it begins to transition into the plastic stage,(yield) at 14 it's in the work hardened stage (ultimate yield), and by 12 it's beginning to neck down and headed towards breaking.
This is a stress strain diagram in action.
Bullet alloy is no different. Whomever lead you to believe there is something called work softening is in error. It's a one way street once it hits the plastic stage without any kind of reshaping/normalizing/stress relief.
Now as for this post From WCI:
quote:
What you have created is a paralax matrix that can not be identified or solidified by the hardness of the rockwell with out he third lunar eclipse aligning with the fourth Sunday in March. Then and only then will you have achieved the knowledge you seek to obtain your answer.
Signed
Grasshopper
It's the forth lunar eclipse on the 2nd Sunday in July.
Jim Stark
QUESTION????? If you quench a cast bullet(s) right out of the mold... and this hardens the surface...What happens to that hardened surface when you run them thru the sizer????
Thanks,
JIM..............
Part 1
Alloy has everything to do with shrinkage percentage. When you cast a bullet that has been overly sized, it will remove the layer of hardness induced by the quenching. The entire bullet is not = in hardness in the through sectional, therefore you have to pay attention to alloy and the resulting dimensions. The closer you have to final size from the mold, the more you retain the hardness layer.
If you want more hardness, increase antimony to 6%, if you want less, drop it to 2%. An increase in antimony decreases the time required to exit the lower side of the transformation range, which in turn increases the hardness.
You can also add trace levels of arsenic (1/4% of 1% or so) and this will also increase the effect of hardening/and depth of hardening through quenching. 1/2 to 3/4 of 1% will get you into the brittle range where it will shatter when it hits steel with sufficient velocity. (all predicated on .5% max or less tin, 5-6% antimony, and remainder lead)
Part 2
quote:
dandak1
Don, your link has an answer in it...the fellow at LASC tested 10 year old heat treated bullets and found they had only softened a little. That was what I needed to know. I can go ahead and load up 200 or so rounds and if it takes me a year or so to go thru them they will still be as hard as when I cast them. I also learned NOT to skim off the antimony from the top of the melt (I had been doing that but didnt know it was antimony). That article was excellent. Thanks again.
quote:
Jim Stark, read the lasc article, he answers your question, basically running them thru a sizer can work soften them. I dont size my bullets so I didnt pay much attention here, but believe he says to size them before he oven treats them. If you water quench like I do, well, sizing may work soften the surface which is probably not what you want.
Plan on (finally) having some time to myself this weekend, where I will read the other links that readers have been kind enough to post. Thanks guys.
There is no such thing as work softening for metals in the context that is stated here. A standard stress strain diagram will show that it first passes through the elastic range (range at which it will return to it's original shape if bent AKA yield strength) then it will hit the plastic range (range at which a metal does not return to it's original shape but no exactly in the work hardening stage yet. The peak of which is known as its ultimate yield strength and the lead up to it being known as it's strain hardening region) Then it gets to the work hardening stage at which it becomes brittle and starts necking down and eventually snaps (brittle fracture).
http://www.optics.arizona.edu/optomech/references/OPTI_222/OPTI_222_W4.pdf
A good basic article on metallurgy designed to clue in optical engineers
http://en.wikipedia.org/wiki/Tensile_strength
More of a lay person explanation but still mostly accurate.
Here is a video I have from a tensile test of a weld sample.
http://s128.photobucket.com/albums/p190/CWI555/?action=view?t=tensile.flv
At 26 on the time line it begins to transition into the plastic stage,(yield) at 14 it's in the work hardened stage (ultimate yield), and by 12 it's beginning to neck down and headed towards breaking.
This is a stress strain diagram in action.
Bullet alloy is no different. Whomever lead you to believe there is something called work softening is in error. It's a one way street once it hits the plastic stage without any kind of reshaping/normalizing/stress relief.
Now as for this post From WCI:
quote:
What you have created is a paralax matrix that can not be identified or solidified by the hardness of the rockwell with out he third lunar eclipse aligning with the fourth Sunday in March. Then and only then will you have achieved the knowledge you seek to obtain your answer.
Signed
Grasshopper
It's the forth lunar eclipse on the 2nd Sunday in July.
0
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All good stuff. Like most people I just want it to work. I don't necessarily have to understand the process. A word of caution, generally speaking the harder a cast bullet is the more likely it is to break up on impact. Remember what your origional goal is ie penetration ect. There is a difference in expectation in hunting and target rounds. 0
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