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NDT performed after or before Hydrotest test

mrmalcolm

mrmalcolm

Marine/Ocean
Joined
Jan 24, 2024
Messages
59
Location
CN
Dear colleagues,
Any code mentioned Non-destructive testing should be performed after or before the hydrostatic test?
If non-destructive testing is performed after the hydrostatic test, is it possible that the hydrostatic test could cause minor imperfection to expand into major defects?
If non-destructive testing is performed before the hydrostatic test, could the pressure of the hydrostatic test cause the pressure vessel to explode?
Thank you.
 
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r6155 said:
“To in sure weld integrity”. : INCORRECT
Pressure test is to check a pressure vessel integrity, not only the welds
Hydrostatic pressure test for piping is different for pressure vessels.
Click to expand...
I think you lost it, better take a chill pill
 
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r6155 said:
“To in sure weld integrity”. : INCORRECT
Pressure test is to check a pressure vessel integrity, not only the welds
Hydrostatic pressure test for piping is different for pressure vessels.
Click to expand...
Nitrogen leak test
 
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After Cleaning fittingtack welding and welding atlas centaur oxygen and hydrozine fuel lines, a pressure test is conducted with helium. The welds do leak but it is very very light. Which then has to be repaired or reworked.
 
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I have seen clients specify that RT, PT, and/or WFMT examination of welds be performed AFTER hydrotest for certain applications. Implicit in this requirement is the assumption that hydrotesting could potentially damage welds but I've only ever heard of this happening with austenitic stainless steel vessels that were hydrotested using water relatively high in chlorides.


-Christine
 
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Christine74 said:
I have seen clients specify that RT, PT, and/or WFMT examination of welds be performed AFTER hydrotest for certain applications. Implicit in this requirement is the assumption that hydrotesting could potentially damage welds but I've only ever heard of this happening with austenitic stainless steel vessels that were hydrotested using water relatively high in chlorides.


-Christine
Click to expand...
Our shop had di water. Some of tubing and pipes
Did not allow city water. To many contaminants.
 
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Christine74 said:
I have seen clients specify that RT, PT, and/or WFMT examination of welds be performed AFTER hydrotest for certain applications. Implicit in this requirement is the assumption that hydrotesting could potentially damage welds but I've only ever heard of this happening with austenitic stainless steel vessels that were hydrotested using water relatively high in chlorides.


-Christine
Click to expand...
Hi Christine,
Another Client without a clue. :)
I had similar requirements on my last project with specifications that were about 30 years old from a major US O&G company.
Did not take long to get the requirements waived with a bit of information provided.
Just out of personal interest - how would damage caused by high chlorides be identified by RT ?
 
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DekDee said:
Hi Christine,
Another Client without a clue. :)
I had similar requirements on my last project with specifications that were about 30 years old from a major US O&G company.
Did not take long to get the requirements waived with a bit of information provided.
Just out of personal interest - how would damage caused by high chlorides be identified by RT ?
Click to expand...
The products I was envolved with were for petroleum, chemicals, aerospace.
For many more. Applications varied.
Some of the products haver close tolerance diameters. Some of the materials inconclusive 718, inconclusive 625, titanium, hasteloy, waspaloy, 304, and 316 stainless. The process was unique. Plate sheared, brake formed, swaged, and pulled thru a sizing die.
No catamination was allowed with tap water.
Even the. Shipping paper had to be neutral.
Seam welds where automatic plasma, tig, .
Criteria was for the welds was very critical.
Ut, rt, penetrant. Visual , not in that order.
It depends if chloride contamination was an issue. Rt was not for the parent material.
 
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If NDE is performed after the pressure test and a defect is detected and repaired , a new NDE must be made on the repair and pressure test must be performed again.
Obviously NDE must be performed before the pressure test to protect personnel.
Visual examination must be made before, during and after pressure test.
 
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DekDee I have no idea what the reason is for requiring RT after PWHT, but I found examples of this requirement:


"Nondestructive testing shall be performed, for the main part, during the normal fabrication sequence; exceptions (a) materials shall be tested in their final heat treated condition, and (b) pressure welds shall be radiographed after hydrostatic test."

"Magnetic particle inspection of weld O.D. surfaces after hydrostatic test is substituted for radiography."

"Liquid penetrant tests of weld preparations, back chipped surfaces and weld OD and ID surfaces. The weld ID shall be liquid penetrant tested after hydrostatic testing."



-Christine
 
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