Tack Weld Qualification

[malachiko]

Hello,
I am working with a Chinese supplier (wholey owned factory of our American company). They are tack welding the pins that connect a stem and disc of a butterfly valve. The tack welds are only designed to be in place to hold the pins in and keep them from coming out during service. They are not pressurized or relied upon to bear any stress. However, the valve can be used in dead end service.
Would I be required to have an approved WPS for this weld? Thanks, your opinions are much appreciated.

 

[metengr]

No, technically you don't need a WPS because there is no code or standard that would be enforceable. HOWEVER, if I were you I would qualify a WPS for tack welds because it is the right thing to do and to ensure a controlled process.

 

[malachiko]

OK, thank you. I have to get an approved WPS for Stainless anyway, because we want to do casting defect repair on the body. I should be able to use the WPS to cross-qualify for both. I just wanted to make sure that my only initial concern for the tack welds is to have the process docuemented for ISO.