Dear All,

I am working for flowlines per ASME B31.8 Ch.VIII. While checking material database for API 5L X60, I have noticed that thermal expansion coefficient data for low temperature are not available for temperature lower than 32 deg F. As codes are not restricting the use of the material at the lower temperature range, I think CAESAR II database shall be updated.

Currently I am assuming the expansion coefficient from 32 deg F to -100 deg F as same value as 70 deg F. It would be more conservative.

Please let me know whether it is intended or omitted by COADE.

Check Table 832.2. This is why the CAESAR II material data base stops at 32 degF.

Dear Richard,

Thank you for your response. As specified in the code, I think properties for lower temperature than 32 deg F are to be selected by the stress engineer. As my project allows the use of API 5L X60 only if the impact test results are conforming the specified limit, in my opinion, it should be justified to use same properties as 32 deg F for lower temperatures.

If there is anything I misunderstood, please let me know.

Some years ago, I had occasion to do a lot of work with cryogenic piping sstems. Cryogenic properties are available at good university libraries and in other places. Since you re in Houston, I suggest you spend a few hours at the Rice University library.

Without digging through a lot of old files, I cannot give a definitive answer, and I have no intention of doing your research for you. But my recollection strongly suggests that you do NOT take the course of action you appear to be contemplating without the extracurricular work. You could wind up with a whole lot of egg on your face.

The Code does allow the stress engineer to select properties for conditions outside the range of data that it mandates. But it DOES NOT suggest that you may select them out of a hat. It presumes that you will approach the determination of such properties in a professional fashion. In this case, the implicit assumption is that you will do a little research rather than simply guessing.

X60 is High Tensile CARBON STEEL pipe. You would be out of your mind to use Carbon Steel Pipe at -100F without taking notch toughness issues into account.


Before you make a huge ASSumption you should study up on the basics... "As codes are not restricting the use of the material at the lower temperature range, I think CAESAR II database shall be updated.

Currently I am assuming the expansion coefficient from 32 deg F to -100 deg F as same value as 70 deg F. It would be more conservative"

-100 F is -73 C. X60 is not designed for such temperatures. I would never use it. If you plan to use such pipe what about flanges, bolts...

If you do impact testing in which direction, in which end of the pipe, each pipe, each elbow, is the pipe long welded? Absolutely too risky for me.

"If you do impact testing in which direction, in which end of the pipe, each pipe, each elbow, is the pipe long welded? Absolutely too risky for me."

Me too.... thats why I put my two cents in as I did. I would be amazed to find any high tensile carbon steel that would meet the impact test requirements of B31.3-2004 Chpt III

Mr. Lee has looked at this problem soley from the standpoint of needing a thermal expansion coefficient without thinking of the notch toughness brittle fracture consequences.

Dear Sirs,

I am grateful to get knowlege of the material and the code.

In my case the minimum design temperature of the system is only 20 deg F. My assumption was made considering only for the particular case. But as you pointed out, I should have considered more than I had done.

Thank you for your advices.