NDE before and after PWHT
NDE before and after PWHT
(OP)
Most companies require NDE to be performed after PWHT for P1 materials, however, I cannot find this as being a requirement anywhere in B31.3. I find it interesting that B31.3 states that leak testing should take place after PWHT (implying to me that soundness should be checked for for after PWHT),however, no where does it state that NDE on P1 material should be done after PWHT, which is also a check for soundness. Any thoughts?





RE: NDE before and after PWHT
RE: NDE before and after PWHT
This question has been asked many times before, and the same answer is provided,
ASME Codes/Standards provide minimum requirements for safe long-term operation. For certain base materials, NDT after PWHT is a specific process step that is not addressed because there is no specific concerns regarding sequence. This means all that is required is NDT after welding.
A User can certainly add process hold points for NDT to be done before and after fabrication (meaning welding AND PWHT). For P-No 1 base materials that are readily weldable, I have performed RT after welding and before PWHT and simply used surface NDT after PWHT. Other cases, I have performed both RT before and after PWHT. I like flexibility.
RE: NDE before and after PWHT
B31.3 specifically does not mandate final NDE after PWHT for carbon steel (P No. 1) pipe. I'm not so sure about your statement, "Most companies require NDE to be performed after PWHT for P1 materials..." It has been my experience that most of the Owners/Engineers that we deal with do not.
RE: NDE before and after PWHT
It is the norm that PWHT be performed before leak or hydro testing.
RE: NDE before and after PWHT
RE: NDE before and after PWHT
RE: NDE before and after PWHT
In addition to comments of metengr, PWHT may not have been performed as desired; this was common back when exothermal kits and other marginally controled heating methods were used for localized PWHT (before electric resistance heating and modern induction heating methodes were employed).
RE: NDE before and after PWHT