PWHT for Material SA 203 E

Dear Members,

Regarding to material as above(SA 203 E), I refer to the ASME Section II, part D table 1A 2007 Edition, this material fall in P-No. 9B, Group No. 1 and then I go through to the ASME Section VIII part UCS-56 (Requirement for Post weld Heat Treatment). From table UCS-56, Note 3(a) Material over 16mm nominal thickness is mandatory for PWHT.

As per my design shell thickness is only 12.7mm, So as per my understanding PWHT is not required. I'm correct? because some people argue about that.

Could anyone support me regarding this matter?

Best Regards,

Faizol.