×
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

Chloride Stress Corrosion - Pressure Safety Valves

Chloride Stress Corrosion - Pressure Safety Valves

Chloride Stress Corrosion - Pressure Safety Valves

(OP)
I have a philosophical discussion going concerning acceptable materials for pressure safety valves used in seawater.  Our specifications require ALL Monel materials for the valves.  These safety valves are low pressure units (ANSI Class 150, relief pressure 180 psig, 90 degF).  The reason the specifications call for all Monel construction is to prevent chloride stress corrosion.  I would like to utilize PSV's with carbon steel body and bonnet with all-monel wetted internals.  My thought is that under normal conditions, the Monel parts are the only components in contact with the seawater.  Only if the PSV blows due to overpressure will the carbon steel components contact seawater.  This situation would be very intermittent (maybe never) and when PSV's blow they require attention anyway.  The stress is low on the cast (ASTM A216 WSB) carbon steel, as far as I can judge.  I realize that this approach is a compromise but the cost and time to delivery could justify it.

Please let me know what the big world thinks about this.

RE: Chloride Stress Corrosion - Pressure Safety Valves

Hi
You may go to check out NACE RP-0475 which reffres to High Chlorides services with Cl > 90000ppm.

There you will find the answer.
If you will try to buy from NACE by phone is better.
You will get the pdf format fast maybe same day.

Pat

RE: Chloride Stress Corrosion - Pressure Safety Valves

RE: Chloride Stress Corrosion - Pressure Safety Valves

You are right, is the best for chlorides.
Monell construction is OK on this service, however check wih this stanadard NACE RP-0475 which is only for high chlorides services designed.
You have to stay awy far away from SS.  

RE: Chloride Stress Corrosion - Pressure Safety Valves

Valve....

Is it possible for you to use a rupture disc/Relief valve combinaton..?

The rupture disc can be made from a premium material 9titanium..?) and the relief valve can be made from less expensive materials.

The disc, of course, must be replaced after actuation and the valve would require cleaning.

-MJC

   

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