What's the ASME Minimum Tubing Thickness for Orbital Welding?

Are you butt welding two tubes together or welding a tube to a tubesheet.

In general Section IX doesn't cover joint design. That would be part of the design code (Sections I, III, VIII-1, B31.1/2/3, etc...)

Section IX gives a range for qualification. If you qualify a WPS on 0.035" material, it will generally be qualified from 0.5x to 2x of the qualified thickness (0.017~0.070"). Likewise there is also a range for the tubing diameter.

When we do tube-to-tubesheet WPS qualifications, we generally have to do one for every tube diameter - tube wall - material - joint configuration combination that we use.

Thanks for the response Lawrence,

Tube to Tube, When I coupon in, and cut open the weld after and inspect the inside, I measure the inside weld bead width. Ernie Benway said it must be minimum twice the wall thickness ie .035"Wall , .070" minimum to pass Section IX or it is a failure.

Cbraet

The 2 X rule is for the welding procedure qualifications, PQR, as well as the welders qualification, it means that if the procedure you were qualified under is for 1/4" .035 Wall tubing, you are only certified to and qualified to perform welds for up to 1/2" .070 Wall tubing, Nothing bigger.

vmg