PWHT Requirement

1.5" = 38.1 mm. Maybe that will give a hint. Also, you seem to have a copy of the Code. Did it say over 1.5", or equal to and over? Did it say over 38 mm, or equal to and over?

Code specifically says to not mix imperial and metric and that no conversion should be made between the two. I know it's frustrating at times, but don't do it.

Use the imperial section, or use the metric section. Never convert between the two.

-A-

Open ASME Sec-VIII Div-1.Search for UCS-56 table for P1 material PWHT requirements. Read UCS-56, Note: - 2 (a) and 2(b) carefully. It is self explanatory and can be used for general service conditions. However, you have to consider other service requirements as per ASME Sec-VIII Div-1 (Eg. Lethal service & Impact requirement) for a detailed analysis before a conclusion.

yes For p number 1 note no 2-b it is clerly speicfy that for welded joint over 11/4(32 mm) nominal thickness through 11/2(38mm)nominal thickness unless preheat is applied at Minimum Temperature of 200 F(95 C) during welding.

Which is more important to you - getting the part finished rapidly and out the door, or getting a reliable quality part?