×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

ASME Section 2 part D Extrapolation

ASME Section 2 part D Extrapolation

ASME Section 2 part D Extrapolation

(OP)
I've done the design study for standard temperature. My part has a max psi of 3000 at standard temp. using a material with an allowable stress of 24ksi. Can i extrapolate the max pressure to 300 psi using the listed allowable stress of 21.2? so 21.2/24*3000 giving a max pressure of 2650 psi. I know there is a linear relationship but is this form of extrapolation allowed or am i required to run the study at the higher temperature.

RE: ASME Section 2 part D Extrapolation

Allowed by who?

Regards

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: ASME Section 2 part D Extrapolation

(OP)
ASME code 16.34 or section 8 div 2 and allowable stresses given by section 2 part D, which now that i'm re-reading my e-mail i didn't stipulate. I think i answered my own question, though as i was looking at the pressure temperature tables for the flanges in ASME 16.5 and it looks like a direct interpolation. going from standard temperature at (-20F to 100F) the 900 class flange in WCB material has a rating of 2220 psi and at a temp of 300 it has a rating of 1960 psi which coincides directly using the allowable stress of 24ksi at standard temp and 21.2 ksi at 300F.

Calculation: 21.2/24*2220 = 1960 which matches the 1965 in the spec. The same is for the class 1500 range as well 21.2/24*3705 = 3273 which matches the 3270 in the spec.

So if my valve has a maximum operating pressure of 3000 psi at standard temp then 21.2/24*3000 = 2650 psi maximum operating pressure at 300F, where 24ksi = allowable stress at standard temp and 21.2 = allowable stress at 300F

RE: ASME Section 2 part D Extrapolation

I'm not seeing a direct correlation between the rate that the allowable stress of a material drops off with increasing temperature in ASME Section II Part D and the rate at which the Pressure-Temperature Rating for the same material drops with temperature in ASME B16.5. In fact different flange rating categories (150#, 300#, etc.) in ASME B16.5 drop at different rates for the same material class.


-Christine

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! Already a Member? Login



News


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