# Re: Burst strenght of 430 Stainless Steel Tube

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Posted by John Andrews (209.113.165.108) on December 10, 2002 at 12:52:08:

In Reply to: Burst strenght of 430 Stainless Steel Tube posted by Henry on December 04, 2002 at 14:35:28:

: I'm hoping someone can help me. I have a stamped stainless steel part, a flanged tube. The material is 430 stainless, which has been stamped, annealed and then stamped again at least 3 times into the final shape. The approx dimensions of the part are 1.25" lenght, 1.5" inner diameter and a .050" wall thickness. Can anyone tell me how I calculate a burst pressure for this part? I have a requirement to perform a 400 psi leak test, but want to be sure the material hold up before attempting this.

: Henry

This is a complex question since the part you are testing is not a simple cylinder...it has a flange with dimensions that were not mentioned. The short answer is be careful. The longer answer is as follows:

the yield stress, Sy, of the stainless will define how high in pressure you can go NOT the "burst pressure"(which implies part destruction). If you take a conservative allowable stress from ASME (Sa) not the yield and then compare to the stress in a cylinder, you should feel pretty comfortable. See below:

Sa = 12000 psi
P = 400 psi
ID = 1.5"
t = 0.050"

circumferential (hoop) stress = PR/t = 400*0.75/0.05 = 6000 psi

This is 50% of the allowable stress. You should be OK. However, please note that the flange is likely the failure point. Use water for leak testing and proper safety attire. If a pressure vessel ruptures with any air in it, fragments can do serious damage. Good luck.

John Andrews, P.E.

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