×
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

NACE MR0175 Duplex CRO question

NACE MR0175 Duplex CRO question

NACE MR0175 Duplex CRO question

(OP)
Good afternoon, everyone. I have a question regarding NACE MR0175 Part 3 A7.3

"A cross-section of the weld metal, HAZ and base metal shall be examined as part of the welding procedure qualification. The microstructure shall be suitably etched and examined at x400 magnification.... The ferrite content in the weld metal root and unreheated weld cap shall ve determined in accordance with ASTM E562 and shall be in the range of 30% to 70% volume fraction."

Does this apply to a 625 Ni alloy on a 2205 duplex base material? I am trying to get this passed through DNV and they are requesting me to include this in the testing. I don't see the purpose of looking for the ferrite in a 625 ni filler metal overlay.

What is your take?
Is there a code paragraph that I can give him to change his mind?

RE: NACE MR0175 Duplex CRO question

Your only way out is to get the end user to invoke the demonstration noted in paragraph 2 of Part 3, A.13.1.

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: NACE MR0175 Duplex CRO question

(OP)

Quote (SJones)

Your only way out is to get the end user to invoke the demonstration noted in paragraph 2 of Part 3, A.13.1.

Thank you for that. Have you ever had to do this? How would you go about that?

RE: NACE MR0175 Duplex CRO question

I am an end user, so I haven't had to do it. I wouldn't normally be considering putting 625 on duplex stainless steel either. What's it for, valve seal areas?

The first thing would be to check with DNV as to whether such an end user's statement would get them off your back. If yes, start the email with 'Dear Mr/Mrs End User Sir/Madam.....'

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: NACE MR0175 Duplex CRO question

(OP)
I was able to get DNV to concede. I'm actually unsure what this company wants it for.

This is what I told DNV

"Would you explain how anyone could get a ferrite content of a Nickel based overlay between 30%-70% volume fraction. The only possible way that I can see to do that is to have horrible dilution of the first layer of overlay which would be terrible for any application.

Is there anyone you can check with? I believe that A.7.3 is applicable only to using duplex as a filler metal in a groove type weld. Otherwise there is no root. First layer overlay is not considered a root. You mentioned it could be taken on the first layer, however nowhere that I can find would allow for that in NACE. How far above the fusion line?

Basically if you used a filler metal with 0% Fe and did this test on an overlay, no matter what it would not have the requirements 30%-70%. "

DNV now only wants me to do the 400x magnification.

RE: NACE MR0175 Duplex CRO question

That solves the A.7.3 (non)issue, but it doesn't solve the A.13.1 issue.

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: NACE MR0175 Duplex CRO question

MrGezus,
You have to allow for the possiblity that the specification writer was clueless and may just have cut-and-pasted stuff he/she found on the internet. I've experienced that on a duplex SS spec prepared by a major EPC. Ferrite in 625 just ain't gonna happen.

"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: NACE MR0175 Duplex CRO question

Indeed, but what about the duplex SS substrate?

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.

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