WPS qualification - weld type question

[timsch]

I have a temperature sensing product that has a block at the end to be welded to typically the OD of pipe or tubing to measure the temperature of the fluid inside. The pipes are pressure containing and are ASME code vessels, but there is no pressure differential across the welds at the block/pipe interface. The block has a profile that has a V-shaped bottom where it contacts the pipe, and the welds fill in between the V-bottom and the pipe. This most closely resembles this butt-weld image.

Does the fact that there is no pressure across the weld relax any of the weld procedure requirements regarding limits to the range of thickness qualified, fillet vs groove weld, etc? We typically create our WPSs according to ASME Sec. IX; our process is GTAW.

In ASME Sec. IX, with a groove WPS, all sizes of fillet welds are allowed. Not the same for visa-versa. With the weld described above, could this be done with a fillet WPS? I know it's a stretch, but I'm hoping that there's a loophole somewhere. It seems to me that a non-pressure containing weld would have more leeway, but that is admittedly wishful thinking.

 

[david339933]

See UW-38 Sec. VIII Div. 1
Cannot be done with a fillet weld procedure.

 

[timsch]

UW-38 Sec. VIII Div. 1 is a short section on REPAIR OF WELD DEFECTS. Was this a typo?

 

[david339933]

Sorry, typo. UW-28

 

[timsch]

thanks

 

[Compositepro]

This seems to be a perfect application for an adhesive.

 

[EdStainless]

Or a mechanical clamp.

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P.E. Metallurgy, consulting work welcomed

 

[timsch]

These go into reactors, hydrocrackers, etc. in refineries. It is unlikely that any would accept anything other than the welding that we typically do. The welding itself is not a problem. I was just looking for options in a time-critical application to get a job done. I have access to a fillet weld WPS for our specific exotic base metals, but not a groove weld one.

Nothing ventured, nothing gained. Like I said, I figured it was a long shot, but there is flexibility in the ASME code, and I certainly don't know all there is to know about it. I greatly appreciate all of the combined expertise here.

 

Better define 'pressure across the weld', because it is not a thing I recognize.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[timsch]

Pressure differential across the weld, i.e. pressure containing weld