WPS for butter pad - test specimen question

[timsch]

I've created WPS's for butt joints where there is a buttering layer on one end of a base metal that gets PWHT and then welded to a 2nd base metal that needs no PWHT. ASME BPVC SEC IX, QW-283 seems to be written with this orientation in mind; at least when I read QW-283.2.

I now have a job where I need to build up a 4" x 6" x 3/16" alloy 625 butter pad on the OD of a P5 pipe to then weld temperature sensors to. What test specimen orientation should be used here? Treat it like a butt weld with a 3/16 butter layer and then the weld with the 2nd base metal?

Note: this is a repost from another forum

 

Seems like you are describing weld overlay, although I suppose it could be qualified as a groove weld (P-no.1 to P-no.1 with F43 filler metal), depending on what else you might want to do with this application.

A thermocouple can be attached by low energy capacitor discharge welding, which in B31.3 is described by 328.7 Attachment Welds. No subsequent PWHT is required.

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

 

[timsch]

The butter pad is an overlay on the OD of 4" pipe. What will be welded to the butter pad / overlay will be not just thermocouple wires, but a V-pad tubeskin thermocouple, which is attached with groove welds on each side of the V-pad. Nothing else will be done with this application other than provide the base for these tubeskins.

 

[weldstan]

I have qualified similar procedures in the past (over 15 years ago) just as you stated. Butter the P5 with nickel base alloy at least 1/4" thick after machine beveling followed by PWHT then weld the nickel base alloy to the buttered P5 alloy without PWHT and performed the tensile tests and bend tests assuring both the butter pass and the groove weld was fully incorporated therein. What the Code requires today, I cannot say.