annealing alluminum

[mjh368]

hello everyone,
First i would like to apolozize for my ignorance, i am a plastics guy. At my company we etch .062 alluminum sheet on one side. Removing material from one side causes the sheet to bow and roll.
I was wondering what would happen if i clamped the sheet flat and annealed it. I was wondering if anyone had any comments as far as temperature and time. Also if they think this will work.
Thannks for your time
MJH

 

[mjh368]

i have also read that there are non-heat treatable aluminum alloys. what does this mean?

 

[TVP]

Some Al alloys can be strengthened by heat treatment. This process entails 1) heating to a high enough temperature to dissolve alloying elements, 2) rapid cooling (quenching) to retain the alloying elements in solution, and 3) allowing for age hardening (also called precipitation hardening). The age hardening process usually requires heating the alloy to > 125 C for a period of time to allow for precipitates to form, but in some alloys this occurs at room temperature.

For 1xxx, 3xxx, and 5xxx series Al alloys, the chemical composition is such that they do not respond to the above treatments (no increase in strength). They are only strengthened by strain hardening (cold working).

What is the specific alloy that you are processing? The time and temperature will depend on the alloy and its prior thermomechanical processing.

 

[stanweld]

Assuming that your .062" sheet is cold rolled, annealing can be done at 650F for 15 minutes. As annealing will lower strength will your design permit the lowered strength? Whereas considerable stress relaxation can be achieved at lower temperatures, you may wish to experiment to obtain ideal heat treatment. As TVP stated, you really need to know the alloy grade and present condition - cold rolled, cold rolled and annealed, solution treated and temper condition and the complete required design condition befor you decide whether to anneal or not.

 

[mjh368]

my alloy is 2024. in an ideal world i would not alter the hardness or strength of the sheet just the warp. So i will try some lower temps 550-650 and see what happens.

My next question is should the stress relieving be done before or after etching? I will be testing both.

 

[Goahead]

If processing conditions allow, you could possibly try to form an opposite deformation in the sheet before chemical milling. It should hopefully straighten up.
The advantage would be avoiding annealing.
You could also start from annealed sheets, but then why selecting 2024? Other materials would provide the same strength of 2024-O.

http://www.welding-advisers.com/

 

[mjh368]

The parts go in airplanes, material is chosen by customer. The material must be flat to go through etching conveyer.

 

[stanweld]

Alloy 2024 for airframe applications is most often in a hard temper; any heat treating will adversely affect strength properties. Take a look at Goahead's suggestions.