Section VII Div 1 RT Reqt For Full Penetration Weld ?? 2

[tc7]

Hello all-

We have a necked style flange welded to the spherical head of a pressure vessel (design pressure 1000psi). The pressure vessel is not a code stamped item and is unique to a test site, but we are treating it as a Section VIII Div 1 code vessel anyway.
The flange is an ASTM A105 forging and the spherical head is forged as well. The weld joint is a full penetration weld of the type shown in Section VIII Fig UW-16.1(d), and does not have a separate reinforcement plate. I presume this type of weld means it is NOT a category D butt weld as depicted in Figure UW-3.
The weld requires either a full depth repair of a crack which developed while in service, or we may elect to remove the flange and reweld a new flange with the entire full penetration circumferential weld, same as before.

By Section VII Div 1 requirements, does this weld require RT if it is either repaired or completely removed and rewelded? I cannot find the code citation which will help me to determine this, Please help.


Other info: The flange is 10-inches at it’s O.D and has a 3.83-inch diameter bore. There is about 2 ¼-inch distance between the underside of the flange and the spherical head. (RT, if required would be indeed difficult).

Thanks for any help on this question.
Tom

 

[stanweld]

Only Catagory A & B welds are subject to RT. Your weld description is not a butt weld; therefore, the weld is not subject to RT.

 

[metengr]

This weld would be considered a category D weld by description.

For repairs to an existing vessel use the NBIC, you have other options to verify the integrity of a weld repair or even new installation of a nozzle.

 

[tc7]

Thankyou Stanweld and Metengr -
Aside from my repair, since UW-11 only talks about butt welds and only mentions category A, B and sometimes C welds, that by default this category D, type UW-16.1(d), is exempted from RT ? (Trying to learn and I am looking for the code citation(s) that excludes RT).

Also Metenger, does the NBIC allow MT as the only final NDT?

 

[metengr]

tc7:
Nice to see you visit the forum. For this attachment and wall thickness I would suggest the root, mid-wall subjected to visual and dry powder magnetic particle testing (MT) and after completion of the nozzle weld, perform a final wet fluorescent MT.

Yes, the NBIC would permit this method of nondestructive testing because in lieu of RT you also have the UT option as well. However, intermediate MT is acceptable for this application.

 

[metengr]

tc7:
Regarding your code question, look at UW-11 (a) 4 and (a) 7 for NDT of nozzle butt welds.