PWHT times and temperatures

[engineer54]

What is required postweld heat treat hold times and max and min hold temp?

 

[bpv66]

Need more information. Construction Code, material, thicknesses...

PW-39 for Section I, UCS-56 for Section VIII-1

 

[engineer54]

Section 8 div 1. I know the code has a minimum temp listed. what about maximum temp. I normally have seen 1125 F +- 25 F used. what is code justification for using +- 25 F range.

 

[metengr]

There is no stated maximum because in the event you want to re-heat treat the welded component one can do this under present rules. Typically, the maximum subcritical PWHT temperature is the lower critical transformation temperature for the base materials being joined. The +/- 25 deg F refers to the spread in temperature to allow for some variation - for example 1125 deg F spread would be 1100 deg F to 1150 deg F, and not the maximum PWHT permitted.