[TheForge] Aluminium

[David E. Smucker]

Solution heat treating temperatures are in the 900 F range for most heat 
treatable alloys follow by a water quench.  Solution heat treating is 
different than the heat treating we think of with steel.

"In solution heat treating the alloying elements go into solid solution in 
the base metal.  After quenching they are locked in solution and then 
following aging precipitate to increase the strength and hardness of the 
metal.  Some aluminum alloys  are classified as precipitation hardening 
metals. When a precipitation hardening alloy is quenched, its alloying 
elements will be trapped in solution, resulting in a soft metal. Aging a 
"solutionized" metal will allow the alloying elements to diffuse through the 
microstructure and form intermetallic particles. These intermetallic 
particles will nucleate and fall out of solution and act as a reinforcing 
phase, thereby increasing the strength of the alloy. Alloys may age 
"naturally" meaning that the precipitates form at room temperature, or they 
may age "artificially" when precipitates only form at elevated 
temperatures."

The quote above from Wikipedia because I thought it would say it better than 
I.

Heat treatable aluminum alloys are found in the 2000, 6000 and 7000 alloys. 
(Added copper, silicon, zinc in that order.)  Most aluminum can be anneal 
around 600 F and partial annealed at lower temperatures.

Dave

--------------------------------------------------
From: "Mark A. Pesetsky" <pesetsky at Princeton.EDU>
Sent: Wednesday, May 28, 2008 10:32 AM
To: <munlaw2 at hcsmail.com>; "Blacksmithing List Sponsored by ABANA" 
<theforge at mailman.qth.net>
Subject: RE: [TheForge] Aluminium

> So what is the ht temp of Al?
>
> Yes, be careful with heat on aluminum. A friend had a baked-on fancy
> paint job on a scuba tank done at a body shop. The heat lamp was
> apparently hot enough to alter the structural integrity of the metal and
> it exploded during the filling process. It caused serious bodily injury.
> Ron C
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