Lamination in pipeline material
Lamination in pipeline material
(OP)
As result of inline inspection, some of the anomalies are calsified as "possible lamination", and recomendation is to uncover pipeline and inspect anomaly. After that if it is really lamination which is not parallel to pipe surface, repair should be done.
Question is, HOW TO INSPECT LAMINATION ANOMALY?
We have hand-held US device for measuring wall thickness. Idea from one college is to use that, and device should show "shallow thickness" on lamination point (measure until first lamination surface, not complete through material until other side of pipe wall). If it is not parallel, then moving device should change readout value. Is this realistic and usable way to check anomaly?
Another point is what are possible repair options i lamination is not parallel to pipe surface? I believe that composite wraps are not option? Only cut-out and metal clam shells?
Question is, HOW TO INSPECT LAMINATION ANOMALY?
We have hand-held US device for measuring wall thickness. Idea from one college is to use that, and device should show "shallow thickness" on lamination point (measure until first lamination surface, not complete through material until other side of pipe wall). If it is not parallel, then moving device should change readout value. Is this realistic and usable way to check anomaly?
Another point is what are possible repair options i lamination is not parallel to pipe surface? I believe that composite wraps are not option? Only cut-out and metal clam shells?





RE: Lamination in pipeline material
I must admit i dotn know much about Lamination, however i did some checking and it seems US is the way to go to detect lamination.
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As for the repair, I know my preference is to just do a cutout and replace the section, it costs more and takes longer to do this, but then its done and you know its done right. if you use a clam shell your basically waiting for the pipe to fail and then the inevitable leaking of the clamshell starts, it can make a mess underground and in my opinion you are just introducing way mroe future fail points than you need to, gaskets bolting and the clam shell itself.
If course all that being said it comes down to schedule and economics, if its going to cost a fortune to shut down the line and do the cut out then that might not be practical.
RE: Lamination in pipeline material
Laminations are the result of melting practices used to produce plate. In my experience with pipe exposed in steam or lowe temperature aqueous service most laminations are benign in pipe because their orientation is such that they will not affect the pressure retaining capability of the pipe under the service conditions I mentioned.
Laminations are detected by ultrasonic examination. In some cases, laminations can be detrimental where service conditions require specific notch toughness of the pipe or in certain corrosion environments, laminations can promote cracking of pipe (stress corrosion cracking).
For repair, you are best to replace the section of pipe if laminations are detected by UT and you determine that they are harmful to the pipe under specific service conditions.
RE: Lamination in pipeline material
RE: Lamination in pipeline material
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Lamination in pipeline material
RE: Lamination in pipeline material
Just a little question here about material quality...
One of the biggest diferences between "structural" grade carbon steel and "piping grade" carbon steel is that the piping is supposed to be made by a "fully killed" process.
Some structural grade carbon steel plate is more prone to lamination defects than the equivalent "pressure vessel/piping grade" material
The steelmaking process to "fully kill" an ingot is more expensive...people have a tendency to cheat the purchaser.
Was this steel piping from China ?
Also see :
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-MJC
RE: Lamination in pipeline material
Repair options are detailed in the PRCI Pipeline Repair Manual R2269-01R
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Lamination in pipeline material
After reading Your answers and some other chapters from various books and standards, I think we will uncover pipeline, see if anomaly is in area of some weld or deformation, if there is any visible cracks, and we will try to measure thickness by hand US device to determine if it is parallel or not with surface. If all above seams ok, then repair is not necessary?
However, when pipeline is already uncovered, we will probably reinforce the spots with composite repairs (TDW RES-Q which we have available), and schedule cut-out repair for first pipeline stop of operation.