Fillet vs Butt, Base Metal Thickness

[Snow-Anders]

Studying the ASME BPVC Section IX to figure out if our WPS and PQR are written properly.
Two Production Scenarios:
A) Insert a 5/8" OD Tube .049 Wall SS304 into a hole in a 5" SCH40 Pipe. Then weld on the outside of the pipe and tube.
B) Welding 5/8" OD Tube .049 Wall SS304 to another 5/8" OD Tube .049 Wall SS304, then weld on outside of the tubing.

Two Existing WPS:
331)P8 - P8, no grade specified, base metal thickness .0625-.436, V Groove
330)P8 - P8, SA-249, base metal thickness .035- .070, Fillet

Scenario A) When I look at the weld drawing my opinion is this is a fillet weld since the two parts are at a 90 Degree.
Scenario B) This looks like a Square Butt Weld since the tubes are so small there is no groove and they are on the same plane.
My understanding correct?

Assuming the above is correct;

Scenario A: According to QW-452.6, WPS 331 should work, since we already have PQR for groove weld test? Does the base metal refer to the pipe, the tube is .049" but pipe is within the range? If not how would I change the WPS or make another WPS?

Scenario B: WPS 330 looks like the one? But not sure since the WPS was written for a "fillet" weld but weld is square butt? The test coupon and PQR shows the tubing joining with no groove but labeled fillet. Not sure if I'm being too much of a stickler??

THANKS!

 

[david339933]

Looks like WPS 330 was mislabeled as a fillet weld WPS. By info given looks like a .035" tube was welded with a square groove giving .035" - .070" qualified thickness. If the PQR shows this is the case, you should revise the WPS. This WPS can then be used to join tube to tube for production scenario #2.

As long as there is no groove in the 5" pipe that the 5/8" tube is inserted into, then WPS 331 will satisfy the required fillet weld, as groove weld qualification qualifies all fillet weld sizes, diameters, basemetal thicknesses. If there is a groove in the 5" pipe then you have to be qualified for both basemetal thicknesses per QW-202.4.

You could combine PQR from WPS 331 with PQR from WPS 330 and make a new WPS to cover .035" - .436".

Above assumes no impacts and all other essential variables are the same.