×
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

PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

(OP)
I am looking for testimonials from test labs (or literature) on the frequency that Clause 19.3.4 acceptance criteria is involked for small diameter A312 TP304L pipe.  This will help form a risk argument for the probability of cracks forming during an emergency crimp on a 3/4"nps sch40 pipe.

Here is the quote from A530 Clause 19.3.4:

"When low D-to-t ratio tubular products are tested, because the strain imposed due to geometry is unreasonably high on the inside surface at the six and twelve o'clock locations, cracks at these locations shall not be cause for rejection if the D to t ratio is less than 10."

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

If you calculate the engineering strains at OD and ID, both at 6 or 12 o'clock positions, you can see the ID strain begins to jump aggressively when D/t is less than 10. And the onset strain at ID surface when D/t = 10 is 12.5%. You can compare this value to your cold-worked 304L's elongation at fracture and get a feel how severe is the deformation from flatenning test. Of course the best way is to do several tests.

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

(OP)
salmon2, I have received testimonials from the SANDVIK testing labs in Scranton PA and Arnprior Ont. that cracking is extremely rare.

Would you care to provide a reference for the strain calculation metholology?

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

yamoffathoo, I didn't use any book, but just consider a long half tube being completely flattenned. The neutral plane is the half radius. Original length for OD, half radius and ID are 0.5*pi*OD, 0.5*pi*(OD-t), and 0.5*pi*(OD-t), respectively. Therefore, the engineering ratio at ID is: 1/(D/t-2). Similarly you can set up formula for OD strain. Plot them with varying D/t and you can see what I was talking about.

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

Sorry, Repost with Correction:

yamoffathoo, I didn't use any book, but just consider a long half tube being completely flattenned. The neutral plane is the half radius. Original lengths for OD, half radius and ID are 0.5*pi*OD, 0.5*pi*(OD-t), and 0.5*pi*(OD-2*t), respectively. Therefore, the engineering strain at ID surface is: 1/(D/t-2), which yields 12.5% when D/t=10. Similarly you can set up formula for OD strain. Plot them with varying D/t and you can see what I was talking about.

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

(OP)
Salmon2,

Thanks, fyi ASME B31.12 Appendix D contains strain calculations for dents in pipes.
 

RE: PIPE FLATTENING TEST ACCEPTANCE PER ASME A530

Thank you and I will check it out.

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