[Dixielandjazz] Re: Cryogenic treatment for brass

[Larry Walton Entertainment]

Hal --Tempering is a little different in steel.  Steel is first heated,
depending on the steel, to about 2000 degrees or to the point a magnet won't
stick to it and then quenched in either oil, water or air.  (yes there are
air quenched steels) and that makes them very hard but also brittle.  Te
tempering process is where the steel is re heated to between 400-600 degrees
F. for a period of time depending on its mass and alloy and then cooled.
Steel goes through color changes  from blue to straw color and is used to
gauge the temperature.  After tempering, the steel comes out tough as well
as hard.

Unfortunately I don't know a lot about brass and it's properties except that
it is entirely different than steel.  Brass can become work hardened and has
to be heated to soften it again but that sums up about everything I know
about brass and it's properties.  I guess it's like every other metal and
depends on it's alloy.

I thought that this process was to relieve stresses and since brass behaves
differently than steel could this have an effect?  I think I agree with both
of you on this one but I have never seen it done.  What was the result if
any?

Larry
St. Louis
----- Original Message ----- 
From: "Hal Vickery" <hvickery at svs.com>
To: <dixielandjazz at ml.islandnet.com>
Sent: Sunday, September 25, 2005 10:35 AM
Subject: FW: [Dixielandjazz] Re: Cryogenic treatment for brass


> You've got more credentials than I have since I'm just a chemistry
teacher,
> but since I was in high school back in the mid '60s, I've seen a number of
> demonstrations of metals being put into liquid nitrogen.  Never have I
heard
> any claims from those performing the demonstrations that cooling the
metals
> would temper them.  Heat is also the only method I'm aware of.
>
> Hal Vickery
>
> -----Original Message-----
> From: dixielandjazz-bounces at ml.islandnet.com
> [mailto:dixielandjazz-bounces at ml.islandnet.com] On Behalf Of Robert Smith
> Sent: Sunday, September 25, 2005 9:47 AM
> To: Dixieland Jazz
> Subject: [Dixielandjazz] Re: Cryogenic treatment for brass
>
> As a metallurgist I regard cryogenic treatment as highly unlikely to
relieve
> any residual stress in any metals or alloys. Sress-relieving ('tempering')
> is done by increasing the temperature. Room temperature also relieves
> residual stresses, but usually takes a long time (depending on the metal
or
> alloy). Lead for example tempers rapidly at room temperature, whereas
brass
> takes several decades before the effect is noticeable.
> It would be impracticable to stress-relieve musical instruments because
the
> temperature involved would damage non-metallic parts including the
lacquer.
>
> Cheers
>
> Bob Smith
> _______________________________________________
> Dixielandjazz mailing list
> Dixielandjazz at ml.islandnet.com
> http://ml.islandnet.com/mailman/listinfo/dixielandjazz
>
>
> _______________________________________________
> Dixielandjazz mailing list
> Dixielandjazz at ml.islandnet.com
> http://ml.islandnet.com/mailman/listinfo/dixielandjazz