alluminium tube
I found an alluminum tube in a photocopier with outer diameter 49 mm and wall thickness 7 mm
Is it safe to make it an air reservoir for 200 bar?
It is soft aluminum. what is the lowest yield stregnth of the mort soft alluminum alloy .
Many Thanx
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Something wrong with the formula.
It should read od, not do.
And 10 to 1.5, not 1.5 to 10
If you don’t know the grade of the material, much less the heat treat, Don’t Use it! Period!
Alu. tube is just not that expensive. and certainly not expensive enough o risk your, or someone elses live or well being. Just Say NO!!! LOL!!!
Thank you all for replies
The formula for calculating tube working pressure is called Barlows formuala
Equation:
P = 2 s t / (do SF) (1)
where
P = max. working pressure (psig)
s = material strength (psi)
t = wall thickness (in)
do = outside diameter (in)
SF = safety factor (in general 1.5 to 10)
The Barlow’s estimate is based on ideal conditions at room temperature.
Material Strength
The strength of a material is determined by the tension test, which measure the tension force and the deformation of the test specimen.
the stress which gives a permanent deformation of 0.2% is called the yield strength
the stress which gives rupture is called the ultimate strength
My problem is that I dont know what tybe of alluminum is my tube
Depending on Heat treatment 6082 is between 6061 and 7075 in. So a pretty tough hard alloy. Knowing what you got is important when messing with hp air.
I heard that Hatsan uses the 6082 grade aluminium in their air tubes, the tube having 35mm OD and the WT being 4mm. The Wolverine uses the same 6082 grade aluminium. I dont know the OD and WT of it, all i know is that is larger than Hatsan’s.For who own an Wolverine and knows the dimmensions of air tube, is wellcome to post. I am interested too to use an 6082 tube 40mm x 5mm or 45mm x 6,4mm to make an air tube.
If you don’t know how to do the math then don’t risk your life!
Emad,
I would exercise extreme caution if I was you concerning that tubing. It could turn into a rather deadly experiment. If I am not mistaken, when aluminum is used in air reservoirs, it is a pretty hard alloy. 200 bar is a lot of pressure and you really should not go cheap when you mess around with it.
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Emad,
Just a few observations:
Barlow’s formula is a good starting point when designing the bulk part of pipe or pressure vessel. But that’s the easy part. Connections and end fittings require careful attention, and are usually trickier to get right.
Any high pressure system has design goals, such as deformation under load, number of load cycles before fatigue failure and so on. Such systems need to comply with safety standards set forth by US DOT (in the US). All such goals are verified by testing before a system is considered fit for use.
A “failure mode effects analysis” tells us just how cautious we need to be. A worst case tank rupture could release enough energy (think explosion here) to seriously injure or kill someone nearby.
So, best to be pretty darn careful around compressed gas pressure vessel design. IMHO, these designs are best left to experts with the knowledge and resources to get it right.
-x356b