Repair welding after PWHT as per Sec VIII Div 1 vs B 31.3

[sayee1]

Section VIII division 1 allows some repair welding (with restrictions) after PWHT(correct me if I am wrong) without the need to carry out PWHT again. I am talking of P1 materials. However as per B31.3, The only clause is that the same PWHT temperature and time shall be followed after the repair weld as for the original weld. So if I have a piping joint between two pipes of thickness in excess of 1" for eg, PWHT is required. Now if after PWHT there is need to reweld at one location say 5mm depth , would re-PWHT need to be carried out? Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[deanc]

You must follow the Code you build to.

 

[SHG]

IT DEPENDS TO THE RATIO OF THE DEPTH OF REPAIR AREA TO THE THICKNESS OF THE PARTS TO BE REPAIRED. YOU CAN REFER TO THE "NATIONAL BOARD" FOR REPAIRING WITHOUT SECONDARY PWHT.

 

[danjo]

First of all, i think you want to refer a B31.3 piping to the ASME PVC which are not necessarily similar. The requirement for PWHT between these 2 codes differ slightly.
For your question on re-doing the PWHT after a repair is done, I would say you should, i.e, if I am the client. However such PWHT can be eliminated in cases where it can be proven that there is no detrimental effect to the metal if no PWHT is applied after the repair. But probing this may be difficult since you have to have experience of similar metals in the past.