PWHT P5A

[3lilaggies]

In ASME VIII UCS-56 pg 158, it lists a PWHT temp of 1250F though the old welding engineer has a temp of 1375F listed in the WPS. I can't find any reasons why you would increase the tempature that much. He is no longer here to ask why. If anyone has any reasons or experience with P5a and what they have done in the past it would be greatly appreciated.

 

[stanweld]

Some other codes like ASME B31.1 and B31.3 require PWHT in the range of 1300 F to 1400 F. Also weld hardness may not meet the B31.3, Customer mandated or NACE requirements with a 1250 F min PWHT; as a result a number of manufacturers and contractors use the higher temperature ranges defined in the pipe codes. Many specify 1350 F +/- 25 F.

 

[metengr]

I agree with stanweld. I have seen 1375 deg F specified on many WPS's for use with other Codes and Standards for P-No 5A material. Also, for some welding procedures used to join P-No5A to P-No 5B material, the PWHT temperature will be selected on the higher end to accommodate both alloy groups. Always remember, that you want to remain below the lower critical transformation temperature, which for P-No 5A material is 1480 deg F.

 

[3lilaggies]

thank you both very much you've been most helpful