×
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

Temperature rating of forged flanges

Temperature rating of forged flanges

Temperature rating of forged flanges

(OP)
I am designing a part, in accordance with ASME B31.1, for 900 psig & 900°F, in 316 stainless.  I wish to use a 3/4" forged flange (A 182).  Table 2-2.3 in ASME 16.5, for 316-L grade, only goes up to 850°F, even though Table A-3 in B31.1 appears to allow this material to be used at higher temperatures.  Table 2-2.2 would allow me to use 316 straight grade for temperatures in excess of 850°F, however all forged flanges these days are dual rated.
Can I use a dual rated flange and take advantage of the higher temperatures in table 2-2.2?  Should I make the flange out of A240 plate and go through the flange calculations?
     

RE: Temperature rating of forged flanges

You cannot use dual certified  and take advantage of higher allowable stress. Use the higher carbon version to ensure adequate
 creep strength.

RE: Temperature rating of forged flanges

Using the high carbon version of 316 may be a real problem if you are planning to weld the flange.  You then likely would have issues with sensitization.

Aaron Tanzer
www.lehightesting.com

RE: Temperature rating of forged flanges

I disagree. It is done for high temperature service applications. You need the higher carbon content for creep strength to avoid relaxation. Sensitization will occur regardless because of elevated temperature exposure in service.

RE: Temperature rating of forged flanges

Sensitization occurs in the range of approximately 1250 - 1650 deg. F.  316 is prone to chromium carbide precipitation in this range.  This is of concern during welding if the flange is to be welded. In that instance, the low carbon 316L grade would be required.  The 900 deg. F operating temperature will not sensitize this material during service though.

Aaron Tanzer
www.lehightesting.com

RE: Temperature rating of forged flanges

Understood. Maybe I should explain my position this way, sensitization is not an issue with continuous operational exposure at 900 deg F. If you are concerned with water-wetted exposure at much lower service temperatures, this would be a concern. 316 stainless steel flanges are supplied for elevated temperature service, of which this application certainly applies.

RE: Temperature rating of forged flanges

I agree with metengr about sensitization causing corrosion concerns at lower temperatures.  I have run into these issues with high temperature equipment being exposed to ambient environments during maintenance shutdowns. Don't know if that is an issue here though.  

Aaron Tanzer
www.lehightesting.com

RE: Temperature rating of forged flanges

By the way mrfailure having been in the Power Generation sector for a number of years, I have even seen what is called low temperature sensitization (LTS) where residual cold work from manufacturing a flange was around 10% with no post forming solution anneal, and continuous exposure at 950 deg F  for many thousands of hours resulted in sensitization.  

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