×
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!
  • 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

Jobs

Sour Service Guided Bend Test

Sour Service Guided Bend Test

Sour Service Guided Bend Test

(OP)
CSA Z245.1 specifies that ERW pipe must pass a root guided bend test in order to be qualified for sour service.

My question is: why is a root guided bend test necessary for sour service qualification?


Background: In the process of converting an existing Grade 359 Cat II pipeline for sour service, one of the cutouts met the microhardness requirements but snapped in half during the guided bend test...

RE: Sour Service Guided Bend Test

One might assume that it is because CSA require proof of weld zone integrity that could lower the likelihood of SSC initiation. However, is it valid to apply the requirements for brand new pipe to pipe that has been in service? Did anyone look at ISO 15156-2, B.3 as a means of qualifying the existing material for H2S service?

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: Sour Service Guided Bend Test

(OP)
Steve,

Thank you for you comments, I agree that ISO 15156-2 B.3 may be a valuable test, especially if we encounter more failed bend tests.

The pipeline in question was previously in miscible hydrocarbon service and had no signs of degradation so I am still unsure as to what factors would cause the ERW to fail the bend test?

RE: Sour Service Guided Bend Test

Was the pipe buried with cathodic protection?

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: Sour Service Guided Bend Test

(OP)
Steve,

Yes buried with extruded polyethylene coating and CP since about 1985.

Mike

RE: Sour Service Guided Bend Test

There is a possibility that hydrogen generated by the CP could be playing a role in embrittlement during the test, but that theory gets a little difficult to follow if by "root bend" it is meant that the inside surface of the pipe is placed in tension (use of "root" in an ERW seam?). Ultimately, you will need to examine these failed tests in more detail to identify the fracture initiation point, ascertain the failure mode, and ascribe a degradation mechanism. It would be advisable to do this before embarking on an ISO 15156-2 test programme.

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.

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