// What rectification shall I do on the defective segment on the service point of view?//
Shall be repaired by Qualified WPS for which PWHT holding time shall not exceed the 1.2times of PQR holding time.
I hope you might have given 1 hour holding time for the original joint. the second PWHT may be again for 1 hour. So, your WPS shall support for total 2 hours of holding time.
Moreover, the simulation heat treatment requirements shall be verified for the applicability.
// What are the NDE's required?//
MT/PT on gouged area, reweld, PT/MT on final weld, RT on final weld before PWHT and after PWHT.
// Is a local PWHT mandatory at the repaired segment?//
Since, PWHT is a service requirement, and shall be carried out after repair, may be locally or complete CS.
// Any special precautions for H2 service...//
Hardness shall be carried out after PWHT and shall not exceed 22 HRC
The important point is design temp -80 deg C. The material selected SA516-60 may not be appropriate for such condition. The UCS curve is supporting up to 80 deg F (Not 80 deg C).
If the original vessel is ASME Code stamped, then repair shall be done to NBIC Code with R stamp.
M.Vijayan
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of K.M Hrishikesan
Sent: Tuesday, September 27, 2011 9:14 AM
To: materials-welding
Subject: [MW:12548] defect on circ-seam of H2 service vessel
Dear Mr. Pradeep Goswami & other experts...
We have a newly fabricated Vessel having following details
Vessel: 1200 mm ID X 4550 mm TL-TL
MOC: SA 516 Gr 60
Code of constr: ASME section VIII div 1 2007 edn.
Thickness: shell-20mm; DE-24 mm
Design pr- 32.3 kg/sq.cm; Design temp - 80 deg.C
Service: LPG+Naphtha ; Vessel is designed for Hydrogen service, 100%RT, Fully PWHT; hydrotested ,cleared by TPI, erected at site, yet to be commissioned
Imperfection (a notch or gouge out)of about 3-4 mm deep and 15 mm long observed on weld seam CS-1 (Top Dished end to shell circ. seam joint ) from inside of vessel. Please see the attached image of segment radiographed by us.
My queries...
What rectification shall I do on the defective segment on the service point of view?
What are the NDE's required?
Is a local PWHT mandatory at the repaired segment?
Any special precautions for H2 service...
appreciate your quick feedbacks..
Regards
Hrishi
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
This communication and any files transmitted with it are confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). If you are not the intended recipient or the person responsible for delivering it to the intended recipient(s), please note that any form of distribution, copying or use of this communication or information contained in it is strictly prohibited and may be unlawful. If you have received this communication in error please return it to the sender, and delete the material from any computer. We reserve the right to monitor email communications through normal internal and external networks. We believe but not warrant that the email and the attachments are virus free. The statement and opinions expressed in this communication are those of the writer and do not necessarily represent those of Madina Group, whose registered office address is
P.O. Box 20459, Doha, Qatar.
Tel. +974 44600818
Fax. +974 44603143
Comments