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1618 views
12:51 Dec-20-2009
samit
pipe surface crack
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Please check the attach pic 47 and 53, as asked for pic. Please give your comments. Note that this is a seam less pipe of 9.5mm thick.Although these cracks are visible visually, they are only in surface(no depth, allmost less than 1mm).
In pic. 45, the two lines are crack? Look like a seam in a seam less pipe?

Please provide your experience and knowladge about these.

 
15:45 Dec-20-2009

aldo

Engineering
Italy,
Joined Jan 2009
39
Re: pipe surface crack In Reply to samit at 12:51 Dec-20-2009 (Opening).

can be a stupid question that i make to you: which NDT methods has been used for this tube?

 
16:21 Dec-20-2009

Andreas

NDT Inspector, Specially in the oilfield
Tuboscope Vetco(Deutschland)Gmbh,
Germany,
Joined Oct 1999
126
Re: pipe surface crack In Reply to samit at 12:51 Dec-20-2009 (Opening).

Only the middle picture is clear ,thr other to picture looks out off focus.
The 2 line are most properly a false indication ,looks like mechanical scraches from the mill.
In a seamless pipe when new you will find most of the longitudial orientated defects like seams and three dimensional like overlaps and roll ins.

Regards

Andreas

 
10:23 Dec-22-2009

Phil

NDT Inspector, Radiation Safety
BINDT, MIAQP,
United Kingdom,
Joined Mar 2009
151
Re: pipe surface crack In Reply to aldo at 15:45 Dec-20-2009 .

Hi Samit,

The middle picture looks like you have carried out MT on the pipe is that correct.

As the first picture is a little blurred, but looks like it could be mill marks but not being able to see them properly can not comment further.

Regards,

 
13:05 Dec-24-2009

John O'Brien

Consultant, -
Chevron ETC ,
USA,
Joined Jan 2000
278
Re: pipe surface crack In Reply to Phil at 10:23 Dec-22-2009 .

The indications seem too regular to be anything other than mechanical.
Have you done any PMI across the area to look at chemical changes, also polish and etch for microstructure. Its possible depending upon where and when the pipe was bought its not really seamless and was long seam welded and ground (has occurred in past). Possible that there was a QC problem and the area has been mechanically worked leaving longitudnal roll marks.
You need to go back to the original pipe specs including the actual addition to see if these were detected at the mill and called mechanical marks rather than cracks if they would have been acceptable.

 


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