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[MW:7704] RE: 7685] thicknesses of the corroded pipes?

By Materials & Welding

Hello Redouane,

The piping  as mentioned underneath, is  in-service piping  or new piping  to be installed in service? How big is the corroded area. If the wall thinning is only localized then B-31.3 have provisions for weld repair. However typically for sour services all clients will be hesitant to such repair.

I would say perform a total thickness mapping of the corroded and ground area. If the recorded readings are well below  required minimum design wall thickness( should not include corrosion allowance or mill tolerances) then the issue of rejection will arise, otherwise not.

If you could feel free to share more data,it would be appreciated.

Thanks


Pradip Goswami,P.Eng.
Welding & Metallurgical Specialist & Consultant
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net



-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Brl Pp
Sent: Thursday, October 21, 2010 11:46 AM
To: Materials & Welding
Subject: [MW:7685] thicknesses of the corroded pipes?

Hello Sir,

Is there anybody who can we directed me on the technique for taking of the thicknesses of the corroded pipes?

After sanding inside pipes, this morning we made taking of thickness on two pipes of diameter 42 " Thickness 12.7mm, these pipes were corroded and refused by the customer.

After discussion about sanding and taking of thickness, the procedure of the contractor mentions the tolerances on the thickness of 0.25mm, below this value the pipe will be refused. After taking of thickness on the pipe we chose only four (04) different places.

1) Is the ASME B31.3 codes mention the tolerances on reduces of thickness after sanding?

2) Four (04) places of thickness on the pipe are sufficient?


My regards


Redouane (engineer projects)
Algeria


(PS: SORRY I AM NOT GOOD IN ENGLISH)

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