Phillip,
API-RP 2A-WSD-Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms—Working Stress Design and AWS D-1.1 have restrictions for PWHT on the above steels.
In addition the spec for base metal, API -2W -2000, have the following precautionary note for such(TMCP) steels:-
-
1.2 POST MANUFACTURING HEATING
Due to the inherent characteristics of the TMCP method, plates manufactured to this spec cannot be formed or post weld heat treated at temperatures above 1100°F (595°C) without some risk of sustaining irreversible and significant losses in strength and toughness. If warm-forming is to be required during subsequent fabrication, the tensile and notch toughness properties of the finished component shall be verified and the properties shall conform to the requirements of this specification. The procedure for verification shall be subject to mutual agreement. The plates may be post-weld heat treated at elevated temperatures not exceeding 1100°F (595°C) providing test coupons are subjected to a thermal cycle to stimulate such fabrication operations, as described in S9. Verification or simulation is not necessary for heating at temperatures not exceeding 400°F (205°C).
For a thickness of 3" if the design/ service conditions calls for PWHT, I would think the best option would be carry out through the Simulated Heat Treatment ,see the base metal properties, and then to decide PWHT.
What're the code or specifications for design and construction???
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 Philip, Taiye (Lagos)
Sent: Thursday, July 21, 2011 8:08 AM
To: materials-welding@googlegroups.com
Subject: [MW:11848] POST WELD HEAT TREATEMENT OF API 2W GR 50/API 2MT1 PIPES WITH THK 3''
Hello Gents,
Using AWS D1.1 as project code, is it wise/Professional to carry out
PWHT on joints made from (TMCP PLATES- API 2W Gr 50/ API 2MT1 Gr 50 rolled into pipes with thickness 3'')
Used for TKY joints on jackets.
Note: TMCP - thermo-mechanical control process.
Regards
Philip Taiye
Principal QA/QC Welding Engineer
(EPCM-1 Quality Assurance/Control)
DeltaAfrik Engineering Limited
2nd Floor, City Express Bank Building
Plot
Victoria Island,
Phone: +234-1-461-8508, +2341-461-6137 ext. 1257
Cell: +234-(0)-803-803-1396
Fax: +234-1-262-2418
e-mail: taiye.philip@worleyparsons.com
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