Hi Sakib,
There is nothing wrong to support a weld requiring 2 hrs -15 mins of PWHT as per ASME Sec-VIII,DIV-2, to support with a PQR which was performed with 4 hrs of PWHT (assuming at the same temperature).
As per QW-407.2 -A change in the post weld heat treatment (see QW-407.1) temperature and time range--) is a supplementary essential variable)-
- 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.
If you have to subject the above vessel to 2 Stress Relieving operations, in case of any repair after PWHT then a PQR with 2 hrs -15 mins would not support your welding procedure specifications.
It's always better to qualify PQR's with some additional PWHT time, considering additional weld repair after SR, which may necessitate SR again
Hope this clears your doubt.
Thanks.
Pradip Goswami,P.Eng.
Welding & Metallurgical Engineer/Specialist
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Karthik
Sent: Sunday, April 18, 2010 1:40 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:4849] requirements for PWHT
| hi, the calculated time might be the minimum holding time.also u haven't mention about the holding temperature as per the code and actual holding temperature used in PQR.anyhow during PQR it may be used the lower temperature wuth extra holding time or may be due to the temperature fluxations they have maintain the more holding time or the material thickness used in PQR might be require 4hour holding temperature. If u have any quiries pls.feel free to ask. regards Karthikeyan.S Getabec Energy Co.,Ltd. 379,Moo6,Soi8,Nikhomphatana, Rayong-21180, Thailand. Phone: 0066 38 897035-8 (Off) Fax: 0066 38 897034 Hand Phone: 0066 892512282 --- On Sat, 4/17/10, Sakib <sakib321@gmail.com> wrote:
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