API 5L Grades for Pipes

The higher "X" numbers refer to higher yield strengths of steel. This in simplistic terms allows pipes to be furnished with either higher pressure ratings, or suitability for higher pressures with a particular given wall thickness. The effects can be observed with many design calculations and tools (e.g. see http://www.acipco.com/steel/linepipe.cfm ).

Good Basic answer and reference to ACIPCO's American Steel Pipe division is a good start. Looking to see all responses here on the forum.

qaqcpipeman

Here is some TRL X60 pipe being loaded for shipment to Canada.

salam allikum mr kareem

these types of pipe acc to. API 5L ARE MOSTLY similar in chemical compositions, but very differnet in the mechanical properties i.e x52 means yield strength is 52 ksi (358 mpa ), also, API X65 & API X 52 ARE SIMILAR IN CHEMICAL COMPOSITION BUT VERY DIFFERNET IN THE MECHANICAL PROPERTIES, BECAUSE X65 IS QUENCHED AND TEMPERED

I would add that the higher yield pipe usually tends to be less corrosion resistant. This can have significant impact if the fluid being transported is "sour" (H2S) or has chlorides in it.

At least in the US, (I can't speak to other countries) the strength level x wall thickness used to be dictated by the proximity to population centers. That said, I haven't worked in the pipeline field in years so the standards might have changed since I messed with this stuff. There are different safety factors that apply depending on how close the line is to population centers. Of course, the problem with that is these lines can be in service for decades and land that was way out in the middle of nowhere when the line was laid can find itself in the middle of a population center a few decades later.

I prefer if you get a copy of API 5L.

hi

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http://www.arab-eng.org/vb/t27056.html