Hydro before PWHT

[HABER]

Can we have a final inspection with hydro-test before Post Weld Heat Treatment?
It could save us a lot of time and money.

 

[Cuemaster64]

At least not in B31.3...see 345.2.2 sec b

"Heat Treatment. Leak tests shall be conducted after any heat treatment has been completed."

Hope this helps.

 

[HABER]

We can not. I just found UW40(e) SectionVIII Div.1
Thank you

 

[arto]

Hydro before PWHT would tend to relieve the favorable stresses induced by the hydrotest at concentrated stress areas, so you'd want to do it again afterwards anyway

 

[metengr]

Hydro before PWHT would tend to relieve the favorable stresses induced by the hydrotest at concentrated stress areas, so you'd want to do it again afterwards anyway

No, absolutely not. This is not a normal practice and must be avoided. Certain as-welded base materials can exhibit poor toughness in the heat affected zone region of the weld that can upon hydrotest result in failure.