Combination GMAW & FCAW

I was wondering if you could shed some light on this subject. We have two different processes being used, GMAW and FCAW. The GMAW is used for tacking stiffeners to panels up to 60 feet long the joint configuration is a T joint. The tacks are between 1/8" and 3/16" weld sizes and they vary from 3" to 4" in length about every 18" in between tacks.  The FCAW is then used from a welding gantry, welding over the previous tack welds from the GMAW with the FCAW process with a continuous weld.

D1.1 2010 in table 4.5 PQR Essential Variables. Comparing the processes there are substantial variables. Our thought is to run a PQR using the two processes together on a V groove weld to qualify both processes. GMAW and FCAW using 100% CO2 welding the root pass with GMAW and then the second pass with FCAW mixing the two processes until the groove joint is completed. Clause 4 in table 4.4 groove test figure 4.23 1 G test.

Will this suffice what we're trying to achieve? I appreciate your input on the matter.

Best Regards.
Gabriel M.

Gabriel,
There are a couple ways you could approach this.  First, are PQR's needed?  This should fall under prequalified unless I'm missing something.  If it is, all you'd need to do is write the prequalified WPS using both processes.

If it is not able to be considered prequalified you could do the required PQRs for each process (GMAW & FCAW).  Or, you could combine processes in your PQR's.  A GMAW root would be sufficient, then a FCAW fill and cover.  Don't switch back and forth between processes for the fill and cover, you are qualifying each to a depth (GMAW to about 3/16 and FCAW to the remainder).

Another option might be to qualify these fillet welds using a fillet welded T-Joint just like you do in production.

Keep in mind, all Welders shall be qualified.  If you are using both processes they will require qualification to both processes.

PWC