×
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

Mismatch bores/ Wall thickness - Welding (EN and ASME)

Mismatch bores/ Wall thickness - Welding (EN and ASME)

Mismatch bores/ Wall thickness - Welding (EN and ASME)

(OP)
On a project, for economic reasons, we have pipe which has a thinner wall thickness than standard off the shelf fittings.

Before anyone says to match the wall thicknesses (in an ideal world) you may want to consider the vast range of pipe wall thicknesses available in the EN standards.

Could anyone tell me where I could find the maximum permissable difference in wall thicknesses allowable for welding, I'm aware we may need to grind away some of the material of the fittings.

I have access to most EN standards but only a few ASME standards.

Regards
Paul Hearn

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

assuming the IDs are the same -
while adhering to the applicable Code press/temp calcs for the thinner wall pipe, a tapered weld prep on the thicker fitting should get you there.



 

Steven C
Senior Member
ThirdPartyInspections.com

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

Since ODs are usually the same, its not likely that the ID are.

3/16 inch is a typical limit of mismatch wall thicknesses. No standard I know of covers this, but I don't know all of them yet.  

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

ok, for economic reasons - fit in a piece of pipe that adheres to biginch's reccommendation for both ends - pipe and fitting.

Steven C
Senior Member
ThirdPartyInspections.com

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

(OP)
BigInch
3/16 is approximately 4.7 mm - can you recall where you got that figure from?
I can find an EN standard that indicates the mismatch of a circumference and alignment but doesn't mention anything about mismatch of wall thicknesses.

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

pch1.
Take a look at ASME B31.8, Appendix I  

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

(OP)
Thanks very much Vzeos.

RE: Mismatch bores/ Wall thickness - Welding (EN and ASME)

Having only recently read this I thought back to this thread:
ASME B16.9 requires taper boring for any misalignment between fitting and pipe greater than 1.5mm. Although it seems that this is limited to fitting proof testing rigs.

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