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Welding After Hydro

Welding After Hydro

Welding After Hydro

(OP)
Quick question, is it permissible to weld insulation pins onto 2205 or 904L after hydro test on Section VIII Div. 1 equipment?  What are the restrictions on types of welds, tig, mig, resistance, etc.  The pins are 3.5" long and the equipment has a long trip to job site and may require us to put on insulation pins depending on where the code stands.  Any help is appreciated.

RE: Welding After Hydro

innovation2;
Simple answer is no, not for Section VIII because of impact concerns and the loss of benefit from a hydrostatic test (local yielding of material and work hardening), for new fabrication. There was a request for code revision regarding Sect I on this same issue and the folks from Section VIII shot it down in flames.

RE: Welding After Hydro

metengr is right.  no welding on vessel after hydrotest and if you have to weld then re-hydro.  The code is clear (in a way) see UG-99a(1).  However, you said insulation pins and that leads me to think you are welding to a skirt (ie. a non pressure part) or support.   Is that correct?  If so, then it would be OK to weld onto non-pressure membrane parts after hydro.  

How many times have we hear this request from fabricators who try to induce/trick the owner/EPC responsible equipment engineer to "interpret" the code meaning?  LOL.

RE: Welding After Hydro

(OP)
The QC is certain there is an exception for capacitor discharge welding.  I am under the assumption that it is not allowed after hydro.  Section VIII is vague on capacitor discharge welding.  Only reference I see is UW-37(h).

RE: Welding After Hydro

(OP)
It is allowable in Section 1 and Section 4 vessels but not in regard to Section 8.  

RE: Welding After Hydro

API-650 permits a limited amount of post-hydro welding.  Maybe your QC guy is thinking of that?

Joe Tank

RE: Welding After Hydro

Guys,

I am looking for information on this as well for a utility boiler. Does anyone have the specific line in Section 8 that says this?

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