Brass Rail Repairs

[JIMRPT@AOL.COM]

In a message dated 3/21/99 9:23:17 PM, you wrote:

<< Our practice was to anneal the necks of the brass casings
so that they wouldn"t split after a few firings.  We would stand the
cases upright in a pan of water, heat the upper case until dull red
and then tip them over onto the pan of water.  This was the proper way
to soften or anneal the brass. As I understand it, annealing and
tempering brass is completely different than annealing and tempering
steel.  You must cool the brass quickly not slowly.>>

rduschen@netusa.net;
  Brass is not of a molecular structure that lends itself to "tempering",
brass is hardened or softened by the addition/subtraction of other metals to
make different brass alloys. Also steels/irons with any but the most
insignificant amounts of brass component do not lend themselves to
"tempering".
   Brass however will "work harden", which is what happens to cartridge casing
necks when they are slammed against the chamber when the round is fired, and
as the projectile is forced from the neck by expanding gases.  As you have
noted after several cycles of this the brass necking will start displaying
cracks.  This is "work hardening" the neck and is where "annealing" comes into
play.

  Annealing allows the brass to take on its original designed molecular
structure which has been altered by "work hardening" or just the plain passage
of time and miniscule cyles of expansion and contraction.

  If my understanding is correct the structure is more or less lined up by
"work hardening" and is allowed to retake its design structure by "annealing"
which puts the structure in a more random and therefore more crack resistant
form. ( as noted by the tech who found the "annealed" brass would bend without
cracking far more than the "unannealed" brass would)  Work hardened brass is
just as soft as  newly annealed brass but not as pliable...if that makes sense
:-)

  The reason for 'sudden quenching' of the cartridge cases is to preclude an
early cracking in the throat of the case, or so I was lead to believe.

  Finally, if Brass/Copper/Bronze could be "tempered" the history of this
planet might be completely different and we 'might' all be speaking the Trojan
version of english rather than the Italian version :-), or possibly Bantu, or
Eqyptian.

Same disclaimer applies, "I'm not a metallurgist", just have an interest in
metals.
Jim Bryant (FL)