Section VIII Pinholes Open to Surface - Criteria
Section VIII Pinholes Open to Surface - Criteria
(OP)
All,
Researching acceptance criteria for pinholes and elongated indications open to the surface. The item in question meets acceptance standards for Appendix 6 for MT and Appendix 8 for LPT that can be open to the surface. UW-38 address repair of defects and states pinholes open to the surface shall be removed. Does this mean that pinholes regardless of size, open to the surface are defects and not acceptable?
Thanks in advance
Researching acceptance criteria for pinholes and elongated indications open to the surface. The item in question meets acceptance standards for Appendix 6 for MT and Appendix 8 for LPT that can be open to the surface. UW-38 address repair of defects and states pinholes open to the surface shall be removed. Does this mean that pinholes regardless of size, open to the surface are defects and not acceptable?
Thanks in advance





RE: Section VIII Pinholes Open to Surface - Criteria
RE: Section VIII Pinholes Open to Surface - Criteria
RE: Section VIII Pinholes Open to Surface - Criteria
Not sure how the Code addresses those defects, but I cant imagine it will allow them. Refer to this example of a video showing the pinhole leak I meant. This is a video of a leak though apinhole we found a few years ago in a piece of piping during installation of that piping in a skid.
RE: Section VIII Pinholes Open to Surface - Criteria
I tend to be in agreement with your assessment, however what is the purpose of UW-38? This is my hold back,UW-38 is applied after conducting RT repairs as noted in UW-51. Would any other weld area not RTd be required to meet UW-38? Or just weld repair area?
Thanks guys enjoy the input and learning experience.
RE: Section VIII Pinholes Open to Surface - Criteria
What is the purpose of UW-38? It's simply stating that defects are to be removed and rewelded.
This is my hold back,UW-38 is applied after conducting RT repairs as noted in UW-51. It can be, but it also refers to VT.
Would any other weld area not RTd be required to meet UW-38? Or just weld repair area? I don't see anything in UW 38 that restricts it radiographed joints or to repair areas.
RE: Section VIII Pinholes Open to Surface - Criteria
RE: Section VIII Pinholes Open to Surface - Criteria
Are pin holes which may propagate through thickness the issue or is porosity the issue.
Interpretation: VIII-1-89-88
Subject: Section VIII, Division 1 (1986 Edition, 1988 Addenda), UW-38
Date Issued: May 10, 1989
File Number: BC86-519
Related Documents:
Question: Does UW-38 prohibit all visible surface porosity in welds?
Reply: The Code has no specific requirements in this regard. The Manufacturer shall establish workmanship criteria consistent with the material and/or service requirements.
RE: Section VIII Pinholes Open to Surface - Criteria
You as the client can impose any additional requirements that exceed the code requirements as long as it is reflected in contract documents.
Generally this is by way of a project specification.
Hope that helps,
Regards,
DD
RE: Section VIII Pinholes Open to Surface - Criteria
Is a through-thickness pinhole also regarded a pinhole in this respect, or is surface porosity in general a pinhole? To my believes it matters a lot if it's through thickness or not.
RE: Section VIII Pinholes Open to Surface - Criteria
Pinhole is a non standard welding term that is generally used for castings or surface treatment (painting etc).
As I am sure you are aware if gas is entrapped in molten metal it can sometimes break through to the surface and create surface porosity.
The really small ones are called pinholes (again - non standard terminology).
A through thickness "pinhole" would be extremely difficult on a single run weld, virtually impossible on a multi run weld.
Cheers,
DD
RE: Section VIII Pinholes Open to Surface - Criteria
Google-ing on pinhole shows defects that seem be caused by improper setting on the welding machine like e.g. incorrect downslope.