Limesh,
PWHT is an essential variable as per Sec-IX. Please look under any table from QW-252 onwards.
If I understand correctly: You've :-Low temperature carbon steel impact tested PQR with a PWHT range of 600⁰±10⁰C.
· This PQR will support a WPS with PWHT only. It will not support a WPS without PWHT.
Regarding the max interpass clause QW-406.3, An increase of more than 100°F (55°C) in the maximum interpass temperature recorded on the PQR is considered to be a supplemental essential variable. This does not apply if the PWHT is for C.S is above upper transformation temperature (7230C) or for austenitic S.S , when soln annealed.
As the PWHT in your case is 600⁰±10⁰C. the max interpass temperature clause as above will apply, second clause as above will not apply.
To summarize based on the PQR data(max interpass 1400C), on paper max interpass allowed would be 1950C ( when there's impact requirement), welds shall be subject to PWHT. If you want to refer this PQR for case where PWHT is to be performed but No impact Requirement, you may increase interpass temperature to 2000C.
Hope it clarifies your query.
Thanks.
Pradip Goswami,P.Eng.
Welding & Metallurgical Engineer/Specialist
Ontario Power Generation Inc.
Email-pgoswami@sympatico.ca,
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of limesh M
Sent: Tuesday, September 14, 2010 8:43 AM
To: materials-welding@googlegroups.com
Subject: [MW:6999] ASME SEC IX Code Issue
Dear All,
Design Code: ASME B31.3 Welding Code: ASME SEC IX
I have a Low temperature carbon steel impact tested PQR with a PWHT range of 600⁰±10⁰C.Is this condition giving an exemption for me on QW406.3 to prepare a WPS with maximum interpass temperature of 200⁰C.
Maximum interpass temperature observed during specimen welding: 140⁰C
Regards,
Limesh
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