×
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

Determining Wall Thinning When Bending Pipe
2

Determining Wall Thinning When Bending Pipe

Determining Wall Thinning When Bending Pipe

(OP)
I would like to determine what the minimum bend radius would be required when bending pipe.

The B31.3 code does not specify a minimum radius but does give formulas to calculate the minimum required thickness of the intrados and extrados after bending.  Once can back calculate the minimum radius if the intrados and extados thicknesses were known.

Does anybody know how (if possible) to calculate the change in thicknesses would be prior to bending the pipe?  

If it helps, I am dealing with both 1/2" and 3/4" Sch 80 stainless steel pipe.

Thanks in advance.

RE: Determining Wall Thinning When Bending Pipe

You may find that the best way is to make some tests since thinning can depend of the equipment used and the bending process, ie either hot or cold bending
athomas236

RE: Determining Wall Thinning When Bending Pipe

2
cbrock,

Here are some "worst-case" thinning percentages that I have received from local pipe bending shops in the last couple of years.  May vary for material and diameter of pipe.  I'd think that these numbers are coming from a acomparison of the straight length of pipe to the bent length, and would assume that the bent metal would have the same density as the sraight metal, but I've never really looked at that too hard.

3D  -  18%
5D  -  12.5%
10D  -  8%

Personally, I spec out what pressure rating I want for the bend, what wall thickness the buttweld ends should have, and let them figure out what wall thickness of pipe to start with.

Hope that helps some

RE: Determining Wall Thinning When Bending Pipe

In bending pipe it has been my experience for calculations that if you allow for a 15% thinning of the thickness you are covered.

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