INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!

*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.

Jobs

Crack in P1 Material from Outer side

Crack in P1 Material from Outer side

(OP)
Hello,
I am facing an issue in our Hydrogen line. There is crack on base metal from the outer side. Inside the fluid is Hydrogen and there is no crack. Pipe thickness is 42mm, Process Temp and pressure is 180 oC and 290barg respectively. Plant commissioning date is 1992. In April 2015, I noted down these crack and it is many on the line. Also the line is fully insulated. I would appreciate if some one help me on this to what should be the reason?

Thanks

Regards
Muhammad

RE: Crack in P1 Material from Outer side

Muhammad;
First, do you have a picture or map of the location of the cracks on the OD of the pipe?

This is important because the orientation of the cracks relative to the pipe and location can aid in determining if the cracks were related to fabrication or in-service damage from thermal/mechanical bending stresses.

RE: Crack in P1 Material from Outer side

Also, how often is this line cycled?

RE: Crack in P1 Material from Outer side

(OP)
Thanks very much for your concern. Cracks are not manufacturing or fabrication but it is in-service damage.Crack orientation is in all position like longitudinal or cross section etc.

RE: Crack in P1 Material from Outer side

Are cracks in pipe or at welds or both?

RE: Crack in P1 Material from Outer side

Are they in a straight section of pipe or a bend?
How much indication is there of corrosion under the insulation?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Crack in P1 Material from Outer side

(OP)
Cracks are on the Pipe (Base Metal) only. Not in weld area. They can be found on straight section, but some bend area too. There is no indication for Corrosion under the insulation.

RE: Crack in P1 Material from Outer side

Really all directions, like spiderwebs?
And no leaks right?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Crack in P1 Material from Outer side

290 barg of H2, 180 deg C and nobody has investigated "the cracks" to demonstrate fitness for service? You need somebody on site performing a proper evaluation, not an internet forum.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

RE: Crack in P1 Material from Outer side

(OP)
Yes in all direction with no leak

RE: Crack in P1 Material from Outer side

(OP)
Steve, yes we are working on it and perhaps we change the materials to P11 as it has good experience in tha US and Europe.

RE: Crack in P1 Material from Outer side

Yes Steve, it is one thing if they are only a few thou deep (then probably related to original manufacture) versus them being half way through the wall (just waiting to go boom).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Crack in P1 Material from Outer side

You need to remove a section containing the cracks and perform a metallurgical investigation. You may be able to do an in situ surface replica to determine presence of martensite. This is a pretty heavy wall and you haven't indicated seamless manufacture or heat treatment.

Obviously as both Steve and Ed indicated, UT examination to determine crack depth is imperative.

RE: Crack in P1 Material from Outer side

Out of curiosity what is the pipe dia?

RE: Crack in P1 Material from Outer side

Interesting topic that needs high thnking. In my experience it could be insulation contamination, find the composition of the insulation and see if it has any Chlorides In it, at high temperature this will create the Web type hairlines. The cure, you may have to coat the pipe to avoid contamination.

RE: Crack in P1 Material from Outer side

(OP)
GenB, many thanks. This is what we missed. We shall do it and will check it there is possibility to control the crack....

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!


Resources


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