[MW:9114] PWHT Of 347H

Dear All:

An urgent question:

Base on Project tech Documents we have to do PWHT( in 870°C for 3Hours,Air Cooled) for welding of 2 parts  as A312-347H(12.7mm) to A182-347H(6mm,) together((A182 is as a branch to A312). After performing PWHT we found some  cracks(dept of crack are  from 3 to 8 mm) Just in weld seam.

Joint Information:

Welding process: GTAM + SMAW.

Design Tem: 780°C and Design Pressure is 5.3Barg in convection coils.

Welding consumables are :E347H Esab, Wire ER347 esab.

 

Shall we repeat PWHT after repairing or not?

If reply is Yes, how much time shall be  Holding time ?

Please let me know your STD reference As well.

 

 

Thanks

Bazrafshan