Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Creep temperature without pressure

Creep temperature without pressure

Creep temperature without pressure

Hello all, i have a question for the members of this forum :
we have on site a fuel gas engine who's exhaust gas temperature is around 600 degrees Celsius . These gases pass at atmospheric pressure throw a carbon pipe ( SA-106 Gr.B ) before being cooled .As per ASME B31.3 creep range for this material starts at 375 degrees Celsius .
We have raised concerns to the manufacturer of the skid that the pipe will go into creep , however the manufacturer is arguing that because no pressure goes throw that pipe ASME B31.3 is not applicable and thus it will be no problem if the pipe goes into creep range.
I tried to search in B31.3 but i have found no definitive answer whether creep is dependent on pressure or not.
Please help clarify if the manufacturer is right or we are.( with a quote from any standard is better :) ).
Thank you.

RE: Creep temperature without pressure


These gases pass at atmospheric pressure throw a carbon pipe ( SA-106 Gr.B ) before being cooled
Is this the exhaust pipe and vent the gas to atmospheric?
Otherwise, it should have some pressure to push the gas through the pipe to the cooler(?). Is it correct?
Instead of A106-B, can it be replaced with a SS pipe?

RE: Creep temperature without pressure

Creep deformation requires stress over time at temperature. Although there is may be no pressure, there is still stress due to self-weight. Nevertheless, that may be within acceptable limits.

At that temperature, though, there are other metallurgical phenomenon taking place. Consult a metallurgist.

What are the consequences if this component suffered a catastrophic failure?

RE: Creep temperature without pressure

Self-weight (as pointed out above) adds to the constant vibration forces on that pipe.

Any exhaust pipe is supported at only one end - the outlet is "pointed out towards the sky" (almost be definition) so the pipe outlet forces always act against the middle of the pipe (which is never straight) and so is never firmly supported at both ends.

Only you can determine how far the pipe will droop until it is no longer usable, hits insulation or other engine parts, hits the hole in the sheetmetal around the engine and enclosure, rusts out the sheetmetal from heat and constant vibration, melts the insulation or rubber around the exhaust, or just looks sloppy in the customer's plant.

RE: Creep temperature without pressure

Thank you all for your answers .
A clarification is in order here : this is the path of the gases : fuel gas engine - flexible connection - housing of the flame arrestor - pipe ( this is the pipe in question ) between the housing of the flame arrestor and an heat exchanger that cools the gasses -cooler - catalyst - exhaust.
The pipe is connected to both ends : 1 to the housing of the flame arrestor , 2 to the cooler .

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper – Data Security and Know-How Protection
Our data is constantly exposed to the danger of being intercepted or stolen as it wends its way over global data networks. Data security measures and measures for protecting intellectual property should not, however, first be implemented when data is exchanged – companies must lay the foundation for these measures within their own organization. Download Now
White Paper – Collaboration in the PLM Context
The influence exerted by the Internet of Things (IoT) means that there is a steadily growing need for collaboration in industry. Partners from new industries and areas of application need to be integrated in cross-company business processes to ensure that the lifecycle of smart, connected products can be managed from end to end. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close