PWHT for welding under the scope of ASME B31.3

[James Scrufy]

I need to prepare PQR according to ASME B31.3 for qualification of piping welding (SS 316L to SA-333 Gr 6, NPS 14inc, thickness: 26mm), but reviewing the par. 331.2.3 of ASME B31.3 I am not pretty sure if I should do or not PWHT.

[wgadmin]

By the AMSE code B31.3, par. 331.2.3(b) it is made clear that when you weld dissimilar materials like a ferritic component (at your case SA-333 Gr 6) and an austenitic component (at your case SS 316L) then the PWHT of welded joint shall be as required for the ferritic material and thus taking into consideration the given piping dimensions it arises that you shall perform PWHT at a temperature range 593 – 649 deg. C as required by the table 331.1.1.

[Jubert]

Hello,

Another question here regarding the requirement of PWHT.
What if the line class of piping requires PWHT (regardless of thickness) and the weld between the pipe and reinforcement pad is less 10mm (the throat), does it requires PWHT?
I am just aware that PWHT is being applied only for the through thickness of the pipe. Just need some idea whether PWHT can be waived on the fillet joint between reinforcement pad and pipe for pipe class requiring PWHT.