PWHT requirements for Pressure vessel weld repair

[napster385]

I am working on a Pressure Vessel Requalification project.

Is it required to conduct PWHT on weld repairs of pressure vessel eventhough the original construction doesn't require? The remaining plate thickness is 16mm A516 Gr.70.

Does any code (API 510 or ASME VIII) states some requirement on this specifically for weld repairs?

Appreciate your helpful comments.

 

[pradipgoswami]

API-510, Clause 8.1 alearly states that "All repairs and alterations shall be performed in accordance with the applicable principles of the ASME Code, or the applicable construction or repair code.
Orginal welding was performed to ASME, i.e the design and construction code. As PWHT was NOT called for in the original construction, repairs need not be PWHT-ed. Although not mandatory as per API-510(8.1.6.4.2),controlled weld deposition technique would be advisable as a good repair technique.

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario, Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[napster385]

Hi Pradip,

Thank you for the useful info.

 

[Mr168]

Is this pressure vessel registered with the National Board? If so, NBIC Part 3 has specifics pertaining to weld repairs and PWHT.

 

[metengr]

The NBIC defers back to the original code of construction for PWHT requirements, when possible. If PWHT is not practical, alternative methods can be used. For the above example, PWHT is not required for repairs if the original code of construction did not require it.