Porosity Acceptance Criteria
Porosity Acceptance Criteria
(OP)
Using ASME B31.3 as a reference; why is surface porosity always unacceptable regardless of size, while internal porosity has an acceptance criteria.
Let's assume both are the same size, why does the fact that it's on the surface make it unacceptable?
Let's assume both are the same size, why does the fact that it's on the surface make it unacceptable?





RE: Porosity Acceptance Criteria
Have a look at Table 341.3.2 Note 5,
Regards,
DD
RE: Porosity Acceptance Criteria
(5) These imperfections are evaluated only for welds ≤ 5 mm (3⁄16 in.) in nominal thickness.
I assume it means that for welds below 5mm thick are evaluated. But for welds thicker than 5mm are not evaluated? Does that mean all surface porosity is acceptable or not?
RE: Porosity Acceptance Criteria
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Plymouth Tube
RE: Porosity Acceptance Criteria
RE: Porosity Acceptance Criteria
RE: Porosity Acceptance Criteria
You said "Porosity in thin welds may reduce the supporting ligament to such an extent where in service leakage could occur and there is plenty of emperical evidence to support such failure. "
But this condition would occur for both internal and external porosity. it doesn't give me a reason which explains the difference in acceptability.
metengr,
"Because surface porosity can result in lower fatigue properties since stresses are highest at a free surface"
You said "it can", tehn that to be should have allowed some to be acceptable and then you should have an acceptance criteria?
RE: Porosity Acceptance Criteria
"Because surface porosity can result in lower fatigue properties since stresses are highest at a free surface"
You said "it can", then some sized porosity on some thickness weld should have allowed some to be acceptable and then you should have an acceptance criteria?
RE: Porosity Acceptance Criteria
I don't agree that porosity can obscure the interpretation of surface NDT, as a trained NDT Professional's job is to interpret discontinuities.
RE: Porosity Acceptance Criteria
Review comments regarding fatigue and corrosion (add corrosion fatigue) at surfaces (internal or external) exposed to corrodants.
RE: Porosity Acceptance Criteria
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Reply; No.
Here is a tip, if you have a problem/issue/concern with the code, either attend a code meeting and voice your concern or more important submit an inquiry.