Aluminum 6061-T6 per AMS-QQ-A-250/11 (plate) versus 6061-T6 per ASTM-B221 (extrusion)?

[deadeye]

What's the difference? I am a machine shop supervisor with a staff of two, that's all, not a rocket scientist nor a metallurgist... please don't judge as I didn't ask for this position! We made a long thin part out of extruded aluminum rather than the plate stock that was defined on the print, assuming the print to be 'wrong'. Now I need to know what effect the difference in material will have on the finished part, especially with regard to potential issues with mechanical resonances. (stole that last line from the query that came to me)

Can someone provide some explanation? (not sure why our design group wasn't tasked with this)

Thanks for your time and patience with me!
CT

 

[cloa]

Noone would judge you here. You must have a toxic work environment. Such a question is very much an engineering question which many engineers wouldn't be able answer. You defined your problem well and gave sufficient information and that's one big step ahead of other posters. Just try to relax a bit.

http://www.eng-tips.com/threadminder.cfm?pid=1529

Use translation assistance for Engineers forum

Note the rules include No Student posting

 

[TVP]

There won't be any difference in terms of chemical composition. Plate is rolled, which is obviously a different manufacturing process from extrusion. This means that the microstructure will possibly/probably be a little different in terms of grain orientation, average grain size, distribution of second phases, etc. Unless this application is very critical for fatigue and fracture properties, it will likely perform similarly using either product form. Natural frequency and vibration are most significantly affected by the density and elastic modulus, which will be the same for either product form.

 

[mrfailure]

Great question, actually:

First, AMS QQ-A-250/11 has been canceled as of 2008. It has for 6061-T6 been superseded by AMS 4027. My comments only apply to QQ-A-260/11.

Compositions are the the same for both alloys.

However, Mechanical properties are a little different: QQ-A-250 11 specifies 42 ksi minimum tensile strength, 35 ksi minimum yield strength, and 10% minimum elongation (at 0.249" maximum thickness). B221 specifies 38 ksi minimum tensile strength. 35 ksi minimum yield strength and 8% minimum elongation to 0.249" and 10% over 0.249". Also, QQ-A-250 has bend test requirements while B221 does not.

Aaron Tanzer

http://www.lehightesting.com

 

[cloa]

He'll probably want to ask what if we get 6061-T6 AMS 4027 and what difference does it make for me as a machining supervisor- the latter answer is probably not much but deadeye can post a thread that links to this one in Machines and Machining forum
Deadeye, I hope you aren't annoyed by my explicit advice but supposed engineers have trouble with this basic advice- don't double post- post a link to your main thread.

Just write:
I have this thread in Metals and Metallurgy Forum.

http://www.eng-tips.com/viewthread.cfm?qid=347488

In this subforum:

http://www.eng-tips.com/threadminder.cfm?pid=281

http://www.eng-tips.com/threadminder.cfm?pid=1529

Use translation assistance for Engineers forum

Note the rules include No Student posting