Andreas NDT Inspector, Specially in the oilfield Tuboscope Vetco(Deutschland)Gmbh, Germany, Joined Oct 1999, 126
Andreas NDT Inspector, Specially in the oilfield Tuboscope Vetco(Deutschland)Gmbh, Germany, Joined Oct 1999 126
16:21 Dec-20-2009 Re: pipe surface crackIn 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.
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.