Steel pipe under high external pressure

[ptaa32]

Hi,

We have a steel tube with yield limit 1000 N/mm2.
It is 250 mm long, outside diam. is 76 mm, inside diam. is 60 mm.
It is plugged at both ends.
Inside pressure is 0 (zero) and outside pressure due to submersion is 69 Mpa.

Will this be safe?
How can I calculate what pressure that would be 'catastrophic' for the pipe?

Kind regards,

Per-Tore Aasestrand
Bergen, Norway

 

[Q_Goest]

Hi Per-Tore, welcome to the board. I would use the ASME piping code to determine safe stresses on externally pressurized pipe. We had a discussion on this here:
https://www.physicsforums.com/showthread.php?t=532901
If you don't have access to the ASME BPV code, you might consider using Roark's but I always use the ASME code for this and am not familiar with how Roark's does this and I've left my copy at the office.

Edit: I'm sure there's a piping code in Europe which is equivalent to the ASME code in the US. If this is an industrial application, you will be required by law to perform the structural analysis per the applicable European code.

 

[ptaa32]

Hi,

Thanks for the tip.
It is for a research project, so there is no need for code compliance.
The cylinder will contain some instrumentation, and I only need to know if it will survive the depth. Preferably also what the margins are.

 

[Dong xianming]

Casing Pipe 139.7*9.17 , mark C-75

Who can find this casing pipe ?