Author Topic: 4130 reservoir  (Read 231 times)

38special

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4130 reservoir
« on: April 28, 2021, 08:02:17 PM »
I am wanting to build an air reservoir out of 4130 dom normalized tubing with an od of 1.375 but want it with a 3 to 3.5 safety factor at a 4500 psi fill. I think I'm using Barlow's formula correctly but would like to know for sure the correct wall thickness needed. Thanks


  • NA, Arkansas

rsterne

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Re: 4130 reservoir
« Reply #1 on: April 29, 2021, 09:01:50 AM »
Personally, I would use a 0.120" wall thickness for 4130 CrMoly, which is a standard size.... Using Lloyd's tube strength spreadsheet for the 1.375" OD x 0.120" wall at 4500 psi I get safety margins of 2.7:1 to Yield and 4.1:1 to Burst.... ASME require 3.5:1 to failure, but only 1.5:1 to yield (worst case, after maximum possible cycles), but Lloyd and I always use at least 2.5:1 to Yield.... If you want a 3:1 safety margin to Yield, you would need to increase the wall thickness to ~ 0.150", which is not a common size, the next size may be 0.188" wall.... adding weight and losing internal volume, of course....

Please note, I am NOT an Engineer, you are responsible for your own build....

Bob
« Last Edit: April 29, 2021, 09:05:39 AM by rsterne »
  • Coalmont, BC

38special

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Re: 4130 reservoir
« Reply #2 on: April 29, 2021, 07:58:02 PM »
Thanks for answering my question. Wanted to make sure I wasn't about to build something that wasn't safe.
  • NA, Arkansas