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RE: [MW:6800] wrong holes on header closed by welding-reg

By Materials & Welding

01.The holes closed is a right method?

If you have made a proper bevel and welded with GTAW root, could not be a problem.

02.what will be the strength in future working conditions?

You may provide an additional pad plate on top of it, best alternative could be if space permits provide a nozzle with blind flange.

03.what will be the suitable inspection method at this condition?

Check with remote visual (e.g. video scope) for full penetration. if you are not sure of weld quality better to remove cap, inspect the patch  and re weld the cap.

04.finally ,can accept this or not?

Acceptance and salvage depends on your construction code and client’s./ AI’s acceptance.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Karthik
Sent: Tuesday, August 31, 2010 2:51 PM
To: materials-welding@googlegroups.com
Subject: [MW:6799] wrong holes on header closed by welding-reg

 


Dear all,

in our current job of prefurnace,holes(2 nos.on end of the both side of header) specified in the drawing was wrong.But it was found only after the holes were drilled.

Specification of header pipe as follows.

Material - A106 Gr.B

Dia - 6"

Thk. - 7.11mm

Hole dia - 74

Design Pressure - 16bar

MAWT - 190degree celsius

After that,it was noticed to our engineering departmmment and they revised the drawing and asked our production to close the wrong holes by attach the same grade of material and weld.Now the repair has finished as said above.

But on this hole closed area, we cannot do UT (because of thickness limitation) also RT cannot be done because of the adjacent tubes and elbows.Even we cannot see the penetration of the weld due to endplates were closed on both sides.just we did PT only and there is no defects.

Pls.give your suggestion on the below questions.

 

01.The holes closed is a right method?

02.what will be the strength in future working conditions?

03.what will be the suitable inspection method at this condition?

04.finally ,can accept this or not?

 

Thanks & Regards,

 

(Karthik)

 

Karthikeyan.S

QA/QC Manager

Getabec Energy Co.,Ltd.

379,Moo6,Soi8,Nikhomphatana,

Rayong-21180,

Thailand.

Phone: 0066 38 897035-8 (Off)

Fax: 0066 38 897034

Hand Phone: 0066 892512282

 


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