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ASTM A312 TP 316L yield/pressure test question

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Johnnyoo

Petroleum
Feb 24, 2015
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CA
The lads overpressured a couple spools during a hydrotest in our yard.
The Line class/spec sheet calls for a 345Psi test and we tested at 430psi.
I am trying to figure out how to evaluated the test pressure from the foundry to see if we came close to yielding the pipe.
The MTR indicates hydrostatic test to ASTM A999.
I am having troubel getting a straight answer from our supplier and need a hand here please.
The spools were both A312 TP 316L schedule 10, one was 6" od and the other 4".
I tried to attach a copy of the MTR so hopefully it makes the trip.
Thank you in advance for any and all assistance.
Johnnyoo

 
 http://files.engineering.com/getfile.aspx?folder=53a44f0b-08d2-4756-bfed-6b26613bb66b&file=TP316_316L_MTR_ZHEJIANG_STELLAR_PIPE_INDUSTRY_CO_LTD.pdf
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I rather doubt you have approached the yield strength of the spool material. You can perform a visual examination and surface NDT to check for swelling and cracks, respectively. If neither are found, the spool should be accepted for service. You can also evaluate the hoop stress at the elevated hydrostatic test pressure and compare with the specified minimum yield strength.
 
stress = pressure x diameter/2*wall

For 6" sch10 it should have 6.625" od and a min wall of 0.122"
430x6.625/2*0.122 = 11,675psi stress
This is well below the yield. Don't worry.

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P.E. Metallurgy, Plymouth Tube
 
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