From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold causing
the aluminum to freeze off quicker make a better quality part? Maybe not as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.










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"Bob La Londe" fired this volley in
:

With that thought in mind would a process to rapidly cool the mold
causing the aluminum to freeze off quicker make a better quality part?
Maybe not as good as a forged part, but better than a slow cooled
cast part? I am not sure where I am really going with this, but there
are plastics that are injected into water jacketed molds for rapid
cooling and freeze off. The differences in temperature for those
plastics and water at cooling

Plastics (except for thermo-setting types) are elastic, and tend not to
crack from stress fractures when the surface cools more quickly than the
interior.

A "thick" (relative term) aluminum casting will shrink severely at the
surface while the interior remains expanded by the heat.

I don't think that will work, unless you can put up with stress
fractures.

Lloyd

On Tue, 5 Nov 2013 14:20:45 -0700, "Bob La Londe"
wrote:

From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold causing
the aluminum to freeze off quicker make a better quality part? Maybe not as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.

Or you could simply heat treat the casting after it was removed from
the mold.
http://www.thebloughs.net/hobbies/me...uminum7075.pdf
refers to this.
--
Cheers,

John B.

"John B." wrote in message
...
On Tue, 5 Nov 2013 14:20:45 -0700, "Bob La Londe"
wrote:

From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold causing
the aluminum to freeze off quicker make a better quality part? Maybe not
as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.

Or you could simply heat treat the casting after it was removed from
the mold.
http://www.thebloughs.net/hobbies/me...uminum7075.pdf
refers to this.
--
Cheers,

John B.

Heat treating the casting sounds like a good option, but your link just
teases and taunts me.

"Oops! It's Not HERE!

We've searched everywhere, and we can't find the document you were looking
for. In techno-babel, the document you requested was called
/hobbies/metalworking/.../Aluminum7075.pdf

We're sorry. We called everyone we could think of to help us find it, but
it's just not here.

So, we've notified the Webmaster with all the information so he can fix it.
He's slow, so wait a day or so, and then try again"


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"Bob La Londe" wrote in message
...
"John B." wrote in message
...
On Tue, 5 Nov 2013 14:20:45 -0700, "Bob La Londe"
wrote:

From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold
causing
the aluminum to freeze off quicker make a better quality part? Maybe not
as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.

Or you could simply heat treat the casting after it was removed from
the mold.
http://www.thebloughs.net/hobbies/me...uminum7075.pdf
refers to this.
--
Cheers,

John B.

Heat treating the casting sounds like a good option, but your link just
teases and taunts me.

"Oops! It's Not HERE!

We've searched everywhere, and we can't find the document you were looking
for. In techno-babel, the document you requested was called
/hobbies/metalworking/.../Aluminum7075.pdf

We're sorry. We called everyone we could think of to help us find it, but
it's just not here.

So, we've notified the Webmaster with all the information so he can fix
it. He's slow, so wait a day or so, and then try again"


Found it. Thanks. Also found:
http://www.speedymetals.com/information/Material7.html


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On Wed, 6 Nov 2013 11:56:05 -0700, "Bob La Londe"
wrote:


Found it. Thanks. Also found:
http://www.speedymetals.com/information/Material7.html


Saved!!

Thanks!!

One of the clearest explanations Ive ever seen.


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On Wed, 6 Nov 2013 11:14:48 -0700, "Bob La Londe"
wrote:

"John B." wrote in message
.. .
On Tue, 5 Nov 2013 14:20:45 -0700, "Bob La Londe"
wrote:

From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold causing
the aluminum to freeze off quicker make a better quality part? Maybe not
as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.

Or you could simply heat treat the casting after it was removed from
the mold.
http://www.thebloughs.net/hobbies/me...uminum7075.pdf
refers to this.
--
Cheers,

John B.

Heat treating the casting sounds like a good option, but your link just
teases and taunts me.

"Oops! It's Not HERE!

We've searched everywhere, and we can't find the document you were looking
for. In techno-babel, the document you requested was called
/hobbies/metalworking/.../Aluminum7075.pdf

We're sorry. We called everyone we could think of to help us find it, but
it's just not here.

So, we've notified the Webmaster with all the information so he can fix it.
He's slow, so wait a day or so, and then try again"


---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com
You guys never heard of chilled permanent mold casting of aluminum??
It is a common method of producing high quality aluminum parts.

On Wed, 6 Nov 2013 11:14:48 -0700, "Bob La Londe"
wrote:

"John B." wrote in message
.. .
On Tue, 5 Nov 2013 14:20:45 -0700, "Bob La Londe"
wrote:

From what I have read slow cooling of aluminum allows minerals to
precipitate out rather than remain in a more uniform suspension and or
solution when you cast aluminum. This is why a cast aluminum part is
usually not considered to be as good (and certainly not as strong) as a
forged part where the metal is only heated up enough to be shaped by the
press.

With that thought in mind would a process to rapidly cool the mold causing
the aluminum to freeze off quicker make a better quality part? Maybe not
as
good as a forged part, but better than a slow cooled cast part? I am not
sure where I am really going with this, but there are plastics that are
injected into water jacketed molds for rapid cooling and freeze off. The
differences in temperature for those plastics and water at cooling
temperatures are much lower than that of aluminum and water, but the
potential for a steam explosion in the event of a failure is still there.

Or you could simply heat treat the casting after it was removed from
the mold.
http://www.thebloughs.net/hobbies/me...uminum7075.pdf
refers to this.
--
Cheers,

John B.

Heat treating the casting sounds like a good option, but your link just
teases and taunts me.

Amazing! I went back and tried to reload the reference and not a thing
did I find :-(

However, a little judicious searching and I come up with:

http://www.barrcasting.com/713aluminum.html
who apparently supply alloys for casting
http://www.asminternational.org/port...621e010aRCR D
which discusses aluminum alloys in general
http://www.dtic.mil/get-tr-doc/pdf?AD=ADA425609

And so on.

Casting aluminum alloys is apparently a complex subject and requires
study. I note that high silicon is conductive to fluidity (if that is
a word :-) but also makes it difficult to weld, for example :-(

Likely that if your parts can be low strength you won't encounter too
many problems but if high strength is required then the opposite is
going to be true.

Sorry if my previous gave the impression that it was easy.

--
Cheers,

John B.

On 11/05/2013 03:20 PM, Bob La Londe wrote:
From what I have read slow cooling of aluminum allows minerals to


Completely not what Bob is concerned about,
but fascinating.

https://www.youtube.com/watch?v=1IugvemOyZY



technomaNge
--
jonbanqueer won't understand...