Pipe WPS - "ID Mismatch" Question

By Blaster (***)

Date 06-14-2012 22:27

I am looking at AWS B2.1-1-207-96. It is a WPS for TIG welding steel pipe.

In the allowable joint designs it repeatably states "I.D. MISMATCH = X/XX in. MAX."

Lets say for a given joint it states "I.D. MISMATCH = 1/16 in. MAX."

Can the pipe be fit with up to a 1/16" inside mismatch all the way around the pipe? Which would mean the two pipe IDs could be up to 1/8" different.

Or must the measured IDs of the two pipes be within 1/16"?

Thanks

By Shane Feder (****)

Date 06-15-2012 00:54

Blaster,
It is 1/16" max in any location.
Mismatch (sometmes referred to as Hi/Lo) can be caused by different IDs of two pipes or a pipe may be out of round in which case the mismatch may be in only one location.
Repair of mismatch to bring it within acceptable tolerances would be up to the Engineer,
Regards,
Shane

By MBSims

Date 06-15-2012 01:52 Edited 06-15-2012 02:38

If it says "I.D. Mismatch" then the wording means the difference between the two diameters. If it said "Internal Mismatch", then it would refer to internal surfaces. A 1/16" I.D. mismatch would be 1/32" internal mismatch all around. A 1/16" internal mismatch would be measured at any point on the inside surface and could be all around.

By Blaster (***)

Date 06-16-2012 00:24

Thank You.