According I’m confusing about details in ASME IX as below, please you advice me.

QW-407.2 A change in the PWHT heat treatment (see QW-407.1) temperature and time range
The procedure qualification test shall be subjected to PWHT essentially equivalent to that encountered in the fabrication of production welds, including at least 80% of the aggregate times at temperature(s). The PWHT total time(s) at temperature(s) may be applied in one heating cycle.





Time at temperature 80% in my understanding is

If I have PWHT 2 hours on the job. my PQR must have been qualified with PWHT time at least 96 minutes ,right?




Regards

Nakarin Potidokmai

Welding Inspector

Pluto LNG Project. / Thailand

E-mail: nakarin_welding@hotmail.com

I agree with your interpretation.

Just something else to consider however, if you have repairs, likely you will be required to perform PWHT again after repairs so it's often better to do the PQR for at least long enough to permit 2 (or more) PWHT cycles.

A very good practice is to apply 2,5 times the PWHT time required for production to the PQR test coupons. Of course only if your material will still have the required properites.

so in your example 2 hours production PWHT give a recommented treatment of 5 hours for the test.

If you need to have three PWHT cycles due to repairs in the shop or even later in service,
3 times 2 hours times 80% result in 4,8 hours, which is qualified by the PQR.

That makes sense, right?

DK

Right, but this is a supplementary ess. variable and it applies only when impact testing is required by the Code of construction. Otherwise FORGET IT.