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FW: [MW:4052] Preheat & PWHT values as per API 1104

By Materials & Welding

 

Hello Asif,

 

I referred API-1104-2006 edition for your query. Parallel to API-1104, ASME also has a code on transmission pipelines for hydrocarbons (ASME B-31.4). Both of these codes specifies that preheating, interpass  temperature control, PHWT  as mandatory  requirements for field and shop welds, however the extent of preheating and PWHT (including time and temperature) is left up to the fabricator.

 

In absence of the same follwing one of the requirements. B-31.1 or ASME –Sec-VIII-DIV-1, as you have listed below would be appropriate to follow. Preheating requirements are same for both the codes however ASME B-31.3(Table-331.1.1)  is more specific on PWHT time and temperature and additionally hardness requirements for  welds/HAZ are specified, which helps to control environmental assisted cracking, e.g SCC and others.

 

As regarding PWHT, one has to ensure that PWHT temperature should not be more than the tempering temperature of the pipes., or else the tensile stress will fall after welding and PWHT.

 

 

Hope this would help you.

 

Thanks  

 

Pradip Goswami,P.Eng

Senior Engineer/Specialist(Welding-Metallurgy)

Machine Dynamics & Component Integrity Dept.

Engineering & Training Services Division

ONTARIO POWER GENERATION Inc.

PO Box-2000, RR-55(South)

Nanticoke, Ontario,N0A1L0

Tel:-(519) 587-2201, Ext 3107--in Nanticoke

         (416) 231-4111, Ext 5925--in Kipling,Toronto

Fax: (519) 587-6814

Email-pradip.goswami@opg.com.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of ASIF
Sent: Wednesday, January 13, 2010 9:36 AM
To: materials-welding@googlegroups.com
Subject: [Norton AntiSpam] [MW:4042] Preheat & PWHT values as per API 1104

 

Dear all

how to determine the values of Preheat or PWHT for Cross Country Pipeline Welding (As per API 1104)
Like we refer 330 & 331 tables of ASME B3.3 for process piping
& Non-mandatory Appendix R & UCS-56 of ASME SECVIII div 1 for PV

--
Best Regards;
ASIF IQBAL SYED
CSWIP 3.1-38557,
ASNT-Level II (RT, UT, MPT & LPT)
0091-99750 163 55

THIS MESSAGE IS ONLY INTENDED FOR THE USE OF THE INTENDED RECIPIENT(S) AND MAY CONTAIN INFORMATION THAT IS PRIVILEGED, PROPRIETARY AND/OR CONFIDENTIAL. If you are not the intended recipient, you are hereby notified that any review, retransmission, dissemination, distribution, copying, conversion to hard copy or other use of this communication is strictly prohibited. If you are not the intended recipient and have received this message in error, please notify me by return e-mail and delete this message from your system. Ontario Power Generation Inc.

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