Pipeline material selection issue
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Dear Haihao friends, I have a question. Pipe DN750, made of carbon steel; operating temperature: -15 to -120°C; operating pressure: 5.8 MPa; medium: methane. Previously, seamless steel pipes were used for small-diameter pipes; this time the diameter is a bit larger. If welded steel pipes are to be used, which standard should be adopted? Domestically and abroad.
In my opinion, it is possible to use Q245R or Q345R steel plates to roll into cylinders
This post was last edited by AtlantisH on 2018-8-30 at 15:12. I just checked the standards – GBT 9711-2017, Petroleum and Natural Gas Industry – Steel Tubes for Pipeline Systems, does not permit the use of such tubes in GC1 pipelines.
What standard does this material meet?
TSG D0001? That was 9711.1; I think the new version of 9711 available now can be used
GB/T 20801.2-2006 states that GB/T 9711.1 cannot be used for GC1 pipes, but it does not specify whether GB/T 9711.2 can be used; it only says that welded steel pipes can refer to two American standards. I’m not sure why. I hope this standard will be updated soon.
In your reply, you mentioned that for welded steel pipes, 2 American standards can be referred to. But I couldn’t find any mention of this anywhere. How is that?
Isn’t it just a matter of choosing pipes that comply with GB/T9711, or API 5L? Of course, 9711 is essentially based on API 5L. It’s based on calculations; you can just choose either the L360M or the L415M. Choose either straight-seam steel pipes or spiral-welded steel pipes; straight-seam steel pipes are recommended.
Let me explain: GB/T9711.1 or 9711.2 are the old versions, while the new version is uniformly denoted as GB/T9711-year.
Where did it mention GC1 pipes? How are they classified? But I know that the pipes specified for 9711 can be used for natural gas without any problem; **that’s the case for the West-East Gas Pipeline as well – it’s just that a higher grade of pipe is used there. Moreover, in urban natural gas networks and pipeline systems, pipes of grades L245 and L360, which are part of the 9711 series, are widely used.
Thank you very much. Could you explain why L245Q or L415Q aren’t used?