[MW:9641] RE: 9622] Weld Repair on PTFE lined vessel

Dear Vinod,

 

In my opinion there is no opportunity to repair undercuts in piping with only 2 mm wall thickness. By welding you will definitely damage the PTFE liner inside the piping.

Only possibility is to change weld geometry in such case that it will no longer be a sharp transition from weld to base material (if third party agrees).

You can do this by burr grinding but with such small wall thickness you will have the risk to remove too much material.

In this case I would propose to use high frequency hammering with a pin which have a radius at the front of min. 2 mm.

By this method you not removing any material but only changing welds profile. Beside that the loss of strength caused by the undercut will be compensated by the introduced compressive stresses in this area.

 

Met vriendelijke groeten / Best Regards

 

Herman Pieper

 

Pieper Quality Support & Inspection

Phone: +31 (0)521 380083

Fax:     +31 (0)84 7539225

Cell:     +31 (0)6 51691215

www.pieper-qsi.nl

 

Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens Vinod Kataria
Verzonden: dinsdag 1 februari 2011 8:12
Aan: materials-welding@googlegroups.com
Onderwerp: [MW:9622] Weld Repair on PTFE lined vessel

 

Dear All,

Please see the attached photo for the undercut and advice if it is possible to repair this on PTEF lined vessel the vessel. The size is 2” NB and wall thickness is 2mm with inside PTFE lining of 4mm. We have imported this vessel from Germany but during 3^rd party inspection it is rejected because of this undercut. The working pressure of this vessel is only 3.5 bar and its successful withstood a hydro test pressure of 10 bar.

Now I request all the expert to please advice if we can repair this undercut if yes than please provide me some guideline or some procedure to carry out this repairing.

Thanks in advance for your kind help.

With kind regards,

Vinod Kumar Kataria

GM - Operations

Bliss Anand Private Limited,

92B/93B Sector 5

IMT Manesar,Gurgaon,

National Capital Region Delhi.

India .

Phone : +91-124-4366000 (9 Lines)

Mobile Phone : +91-9560199004

Fax : +91-124-2290884

--
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.