×
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

Fasteners for Marine/Offshore and Sub sea application

Fasteners for Marine/Offshore and Sub sea application

Fasteners for Marine/Offshore and Sub sea application

(OP)
Our client is concerned about the rusting of Fasteners (Including SS B8M grades) hence has asked for coated fasteners (For all fastenersa) cut accross the applications.

I am concerned about the coated fasteners(Run in thousands of various sizes) because its inherent tolerancing problem. Especially in high pressure aplications since when the fasteners are produced/Manufactured (enmass).

It is very difficult to verify whether the manufacturer of fasteners are meeting the requirements (Of coating thickness and maintaining tolerances). We are at sole mercy of the fastener manufacturers.

Now corrosion is a real problem, is coating the only solution. Our client is insisting on coating even 453 Gr 660 fasteners 9Which is duplex grade) my understanding is that Duplex grades are highly suitable for marine application.

Are there better grades(Other than coated B7m, Coated 453 Gr 660 and B8 grades) of fasteners which are better suited for Offshore applications?

Are ther NACE publications which gives guidelines for Fasteners selection?

RE: Fasteners for Marine/Offshore and Sub sea application

Fasteners are available in both duplex grades (the 25% Cr grades are not really seawater resistant, but might work) and in NiCu alloys (Monel to use a tradename).  I have used a lot K-500 bolts over the years.
The other common sewater alloys: CuNi, 6%Mo stainless, and Ti, are far less common in fasteners.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: Fasteners for Marine/Offshore and Sub sea application

Ed,

I posted something in the Corrosion forum as well, and would appreciate your feedback.  My inclination is similar to that of Goahead or the options that you provided, rather than using galvanized steel fasteners.

RE: Fasteners for Marine/Offshore and Sub sea application

Moorthy's post appears to be referring to topside pressure equipment rather than immersed fasteners which allows several views to be taken dependent upon the operating and maintenance practices to be adopted.  If they are in a submerged application, why bother about them when the facility should be equipped with a properly designed CP system?

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/

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