Alu alloy selection automotive cockpit frame

[choddiec]

Hi, I am trying to select between A5052 and A6082 alloy for CNCing a large frame to bolt to the top of a magbeam. The machined frame needs to hold dimensional accuracy as far as possible.

Can anyone suggest what might be the better choice to avoid twisting of the frame during machining, while at the same time having as much vibration dampening in service? My understanding is that 5052 has good vibration properties but is not heat treated and therefore may be less stable i.e. there could be some risk of twist. I can't find anything on 6082's vibrational properties however.

If neither is any good, other 5000-7000 wrought selections can also be considered.

 

[SwinnyGG]

Well..

My understanding is that 5052...is not heat treated and therefore may be less stable

"5052" has nothing to do with heat treat or temper condition- it is an alloy designation. The number which comes after the alloy designation tells you the temper condition.

With that said, 5052 is traditionally used in sheet form for cold formed (bent, deep drawn) products. It does not machine well when compared to 60XX alloys which are more common. Unless your part has bends, there's no good reason to use it.

With regard to this question:

while at the same time having as much vibration dampening in service?

3

No aluminum alloy is going to exhibit more 'vibration dampening' than any other aluminum alloy. Your parts are going to act like springs unless you add dampening through some other means.

 

[choddiec]

Thanks jgKRI,

Unless your part has bends, there's no good reason to use it.

Ok, this is machining from a solid block so I guess say a standard product like 6082-T6 will be ok.

No aluminum alloy is going to exhibit more 'vibration dampening' than any other aluminum alloy. Your parts are going to act like springs unless you add dampening through some other means.

The mechanical design will include damping.

 

[MikeHalloran]

I love machining 2024-T3ish, which cuts like butter, makes beautiful chips, and is as strong as steel.

The strength comes from severe cold working, so it will distort as you relieve locked in stresses.

However, if you rough and finish machine, sneaking up on the geometry you need, it might be worth a look. ... if you environment is benign.

Mike Halloran
Pembroke Pines, FL, USA