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

Corrosion rate of steel in seawater.

Corrosion rate of steel in seawater.

(OP)
I have been searching through various standards with regards to determining a corrosion rate for steel in water. I basically have a component which is connected to the bottom of a turret on a FPSO made from ASTM A182 f22 (approx 30m below the surface at 30 deg C). The component has an epoxy paint system all over and is cathodically protected for the most part, except from a portion on the inside which has to be accounted for via an allowable corrosion allowance. I know this is dependant an numerous thing such as temperature, oxygen etc, but there must be some standard corrosion rates available for such an instance. Currently I have assumed an average rate of 0.15mm/yr. The only standard I have found of any use is a DNV position mooring chain standard but feel this is not particularly applicable due the material type. If anyone could offer any advice this would be much appreciated.

Thanks

RE: Corrosion rate of steel in seawater.

The problem is: there is no standard seawater. That aside, if CP is not reaching the surface under consideration, then it is possibly occluded from the bulk seawater environment which could have a strong influence on corrosion rates. Comparison with data from the NACE Corrosion Engineer's Reference Book would suggest that 0.15 mm/year could be considered as conservative for several ocean locations. A paper that may be of use is:

R E Melchers, Modeling of Marine Immersion Corrosion for Mild and Low-Alloy Steels—Part 1: Phenomenological Model, Corrosion, Vol 59, (4), 2003, pp 319 - 334

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: Corrosion rate of steel in seawater.

(OP)
Thanks for the reply I will take a look

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