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


CDU Overhead Piping - Materials of Construction Best Practices

CDU Overhead Piping - Materials of Construction Best Practices

CDU Overhead Piping - Materials of Construction Best Practices

We have planned all the necessary corrections for diameter, injection, etc.
At the moment we view Hastelloy C276 as 'industry best practice'. Can anyone validate that with refinery experience?
Is Inconel 625 an acceptable alternative, given that it is easier to work with roll-bonded I-625?
I would also like to get opinions on roll-bonded vs. solid vs. weld clad.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

RE: CDU Overhead Piping - Materials of Construction Best Practices


I think the best alloy strongly depends on the corrosivity in your system.
We have 625 in one CDU and alloy 59 in another one. Both perform quite good in there respective conditions. T
he alloy 59 was used in a system where strong salt formation and relatively sour media are present.
In my experience there is no difference in performence btw. roll-bonded and weld clad alloys in CDUs.
Since the hydrogen partial pressure is no issue here disbonding won't be a problem.
Of course you have to be carefull with the dillution of the base metal and need sufficient passes when you weld in order to reach the specification limits of your alloy (especially Fe-Content). Solid CRA we only use for small bore piping or small nozzles.

Daniel Breyer
Inspection Engineer


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!


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