Dear Pankaj,
A change of PWHT time and temperature is a supplementary essential variable (when impact test is required as per design) in ASME BPV codes. You may use the PQR with PWHT @ 620-650 deg C for buttering on a vessel of P1 base metal subject to PWHT @ 510-540 deg C.
However if there is any specific requirements from client, especially for oil and gas especially sour service or any petrochemical services, then PWHT time and temperature is deemed to be an essential variable (not by code but by client's spec), The single biggest function of PWHT is to reduce, residual stress and control hardness a systematic fashion so as to increase equipment integrity for such services.
Thanks.
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of pankaj kolhe
Sent: Saturday, February 19, 2011 1:32 AM
To: pgoswami@quickclic.net; materials-welding@googlegroups.com
Subject: [MW:9937] pwht
I have a job of p1-p4 material. in that pwht is mentioned 510-540 Deg C for 10 hrs
shell is of p1 material and skirt is of p4. shell to skirt is a closing seam of 22 thk
in this but joint i do buttering on p4 by 7018.
I have pqr of buttering with 620-650 deg c SR for 135 Min soaking.
will it be applicable for above requirement
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