×
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

Galvanic Corrosion Test

Galvanic Corrosion Test

Galvanic Corrosion Test

(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.


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.

RE: Galvanic Corrosion Test

(OP)
That is one of the problem. There is no Standard Test method. The method of testing is as per the written practice of the user


Using SCE electrode and Test Solution is Sea Water (With H2s Purge)

RE: Galvanic Corrosion Test

Probably standard synthetic seawater, there is an ASTM for making it.
A standard saturated calumel electrode, not a big deal.
Then you have figure out how to set it all up.
Often you take the samples and mask them with epoxy, except ofor a controled size (1 sq cm)spot in the area of interest.
There is an ASTM for taking galvanic measurements, but I cant recall what it is.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: Galvanic Corrosion Test

Why not just make a large weld,  cut out a sample, and connect it via a zero-resistance-ameter to the base metal in seawater, and see what direction current flows.  That should be all that's needed to determine which material is anodic and cathodic.

RE: Galvanic Corrosion Test

You could, but it is just as much work.  Cut smaples, bond lead wires, seal backs and edges, make sure that equal areas are exposed, then take measurements.

You can buy sample holders that use a gasket to expose a controled area.  Of course you need flat samples.

Has your customer ever done this test themselves?  Do they give resolution, precision limits?

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: Galvanic Corrosion Test

Another question, perhaps related to the welding engineers:  arn't most weld wires formulated so the resultant weld wire is slightly noble compared to the base metal?,  and could this information be obtained from either the electrode manufacturer or one of the welding professional societies (AWS, Edison, etc)?

RE: Galvanic Corrosion Test

What are the metals you're using?  There are tables to check anodic/cathodic relationships.

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