×
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

Cathodic Protection-Galvanic Corrosion Test of Sub Sea Pipe Line

Cathodic Protection-Galvanic Corrosion Test of Sub Sea Pipe Line

Cathodic Protection-Galvanic Corrosion Test of Sub Sea Pipe Line

(OP)
Hello All

Background:

The specification states that the Weld shall not be Anodic with respect to Base material, This statement appears as the acceptance criteria under Galvanic Corrosion Test of the Pipe Procurement specification.

The Specification does not refer to the standard test method and the specification does not mention the test duration or the test solution and the tesing arrangement.

Now the queries:

1) What are the numbers of the  ASTM or DNV or EN or ISO or NACE standard for testing Pipe Line Weldments to determine whether the Weld is Anodic with respect to pipe basematerial

2) Suppose the potential measured of the pipe base material is "- 0.5" and the potential of the weld is "-0.4" (I persume it is the potential that will be determined as the measure of Anodicity or Cathodicity), is the Weld Anodic with respect to Pipe.

3) Whereas the whole sub sea pipe line is protected by providing bracelet anodes, then what could be the rationale  for asking such requirements in the weldment?

4) Does the international sub sea pipe line standard or codes asks for such requiremtrns when the wleds in a carbon steel sub sea pipe line are going to be welded with carbonsteel electrodes?

5) It is my opinion that the difference between the potential of the weld and the parent material is expected to be very minimal, in the order of the difference in potential between one heat of parent steel and the other heat of steel. What is the difference in potential that is considered significant from the point of view of Galvanic corrosion, that what difference in potential between 2 items will warrent CP protection of a system?

RE: Cathodic Protection-Galvanic Corrosion Test of Sub Sea Pipe Line

Galvanic issues are internal not external. Anodes don't protect.  If you think of an anode as a light bulb, it will only protect what it illuminates.  Please see NACE 1996 conference paper 79.  Hope this helps.

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