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About the test temperature for CTOD test in warm water.

About the test temperature for CTOD test in warm water.

About the test temperature for CTOD test in warm water.

(OP)
We know that CTOD test can be used to waive the PWHT. For offshore platform in high latitude, we normally use DNV requirement to determine the CTOD test temperature:For members above water should be the lowest air temperature, For members below water should be zero(freeze point of water).

This time we are working on a platform in a warm area(lowest air temperature 20 Celsius degree, lowest water temperature about 10 Celsius degree). If we still use the DNV rules, then a zero degree test have to be performed, but it is unreasonable(too low).
So which one should be used:15,10 or zero?
Any other codes have relative requirements?a

RE: About the test temperature for CTOD test in warm water.

Will your proposed materials, welding processes etc meet the requirements at zero C? If so, do the CTOD tests at zero and avoid the conflict. If not,and a 10 or 15 degree temperature rise is necessary to meet the requirments, then they sound marginal for the application!

RE: About the test temperature for CTOD test in warm water.

(OP)
Thank you Carburize!
The Fabricator have a CTOD test in the previous project(same material, same steel mill, same WPS) at 15 degree.
So they want to reuse the test result. I think it is not meet the DNV code requirement.

RE: About the test temperature for CTOD test in warm water.

You should definitely qualify the work using 10 C, not 15 C.

RE: About the test temperature for CTOD test in warm water.

Using just CTOD tested PQRs for waiving PWHT is a crude method. The best method is to go for a fitness for purpose evaluation using ECA.
The latest rev of Total specs GS-STR-301 very nicely addresses the logic to be followed for impact tests, PWHt and/or CTOD.
A 0 Degree CTOD test is not unreasonable with the standard type(s) of consumables used in fabrication and erection of offshore jackets/platforms/pipelines. I feel "0" would be the most appropriate test temperature in your case, because you are not doing any fracture mechanics/fitness for purpose evaluations. If I were the client welding engineer, I would enforce a new procedure to be qualified- wouldn't accept a previously qualified procedure in the case that ECA not being performed, and ask for the testing @0 Degrees C.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

RE: About the test temperature for CTOD test in warm water.

(OP)
Thank you Mr. Sayee Prasad R! I have learn a lot from you.

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