Reducing Wall Thickness Of 6082 Tube - Strength?

[Ianb]

500e on this forum is kindly sorting some 6082 T6 aluminium seamless tube for me, I am wanti ng to use it as an air tube to hold high pressure air, to increase the capacity and reduce weight I was wondering how machining out the i.d and reducing wall thickness from 5mm to 3mm will effect its strength?

i fully understand the reduction in wall and increase in i.d. will reduce its strength, but was wondering what effect if any on it would have on a crystaline/molecular level/internal stresses because of how it was formed into tube?

Is it best to leave as is or will it be fine to thin it as long as the dimensions still work in the pressure calculations?

Thanks

 

[Richard.]

Are we taking about air straight out of a compressor? 100-150psi of pressure?
Are you putting various outlets on the tube to tap into?
Personally I cannot see 150psi of air pressure doing any harm to 3mm wall aluminium.
Any welding you do will need to be decent and use the right consumable if your to avoid springing an air leak.
Of course to answer your question taking 2mm off the wall reduces the tube strength but it’s not going to even remotely come close to reducing it enough for compressed air pressure to have any effect on it.

 

[pressbrake1]

Diameter is the key to wall thickness strength , look at 1/2” ally air pipes maybe a mm thick but 6” would need to be 5mm(this is guess to show what I mean by the ratio)
And what do you mean by high pressure, as Richard rightly say above that airline pressure will not be a problem

 

[Shox Dr]

I think he want to use far more than 150psi. Probably more like 200bar

 

[Richard.]

I think he want to use far more than 150psi. Probably more like 200bar

I missed that part. What’s it gonna be used for then.

 

[Shox Dr]

I missed that part. What’s it gonna be used for then.

Air rilfe?

 

[wyn]

Machining marks internaly might cause points where the stress is raised. It might let go at 200-300 bar.

I'm sure there is a recent thread on " airgun bbs" about aftermarket hw100 cylinders going pop.

 

[Richard.]

Air rilfe?

Are you asking me?
I haven’t a clue. That’s why I asked if it was to do with compressed shop air.

 

[Shox Dr]

Are you asking me?
I haven’t a clue. That’s why I asked if it was to do with compressed shop air.

No. Just reading between the lines

 

[eLuSiVeMiTe]

Original post https://www.mig-welding.co.uk/forum/threads/source-of-7075-aluminium-tube.87709/#post-1269763

 

[Richard.]

I’ve no clue about the pressures involved with an air rifle and completely unqualified to make A suggestion if that’s the case. Sounds dodgy to me to start making/modifying parts for something like that but again I wouldn’t know.

 

[TechnicAl]

I believe there are "schedules" for Aluminium.......have a google......if you can find it you should be able to compare or calculate the strength differential

 

[Ianb]

Yes it is for an airgun so 2-3000psi. It is a scarey pressure, thats why I want to get it right, I will fill with water and pressurise to safely check it before filling with air.

Wasnt sure if anyone knew of any reason that machining the tube was aa problem, but I guess it is no different to cutting threads in the end if I was using screw in end caps.