RE: [MW:12551] defect on circ-seam of H2 service vessel

did you compare this image with the RT taken at fab shop? Did you conclude anything why it was happened?

Did you check visually and measured these dimensions or assumption from the RT image?  Images like this are possible May be due to the thickness difference of shell and dished end. If it is visually confirmed, yes repair by welding is required followed by local PWHT/NDT/hardness check and re hydro

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of K.M Hrishikesan
Sent: Tuesday, September 27, 2011 11:44 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