stress relieving al alloy 5083 'o'

[antd]

i need to stress relieve a part manufactured from aluminium alloy 5083 type 'o'. i am struggling to find any information about temperature and duration required.

Can anyone help or recommend a suitable website with the information on.

many thanks

 

[CoryPad]

MIL-H-6088G Heat Treatment of Aluminum Alloys states that 5083 can be fully annealed (O temper) by heating to 650 degrees F for 2 hours.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[antd]

thanks cory pad, but this is not the information i require.
the part is machined from 5083 type 'o' 'fully annealed' and i wish to stress relieve after machining not anneal it.

regards

ant

 

[unclesyd]

As your alloy is strain hardening it would normally require a full anneal to come back to "O" temper after forming. Being primarily a plate alloy the ALCOA handbook has one mention of what it calls a partial anneal of strain hardening alloys. It call for a temperature of 400°F to 500°F but gives no time. As a full anneal of these alloys only requires the part to fully attain the temperature one would assume that this is true with a partial anneal.

Don’t use a radiant heat (elements exposed) oven.

 

[antd]

thanks unclesyd,

i presume that what you are saying will return the material to its original state after machining?
the part is not plate it is a machined billet(quite large) that is then going to be formed. i want to stress relieve it prior to forming.

ant

 

[unclesyd]

If you are at "O" temper you are about as stressed relieved as possible. You don't need to do a stress relief at "O" temper prior to machining as the block should have heat treated after it was formed.

If you have done any secondary forming work on the block after it was brought to “O” temper, yes I would partially anneal it prior to machining.

You may want to do an intermediate "partial stress relief" after your rough in the part. This may or may not be necessary depending on the amount of hardening (strain) that is done by machining. With the proper tooling this should not be a problem unless you have thin sections.

The aircraft industry and others get by machining Al with very high speed ridged machines.

 

[BTIGUY]

andt

To stress relieve your 5083 parts you can use sub-harmonic stress relief IF your intended goal is limited to one of three reasons: 1. distortion control following machining, 2. reduce delayed distortion, or 3. reduce premature fatigue. This sub-harmonic process should not be used to try to alter the "T" condition of the part or to try to straighten a distorted part.

The website that you can learn more about the process is

http://www.meta-lax.com.

You can virtually use this sub-harmonic process any time since there is no treatment distortion or alteration of the material's mechanical properties. But this process is strictly a preventative mfg. step. Once the distortion is already there, it's too late.

Best of Luck
BTI Guy