If your components are less than or equal to 3/16" then D1.3 could apply. If there are some that are over 3/16" then D1.1 could apply (it actually applies to materials 1/8" and over so there is an overlapping area).
Now, if you didn't catch Lawrence's drift, there is a difference between Welder Performance Qualification (that's for qualifying the person) and Welding Procedure Qualification (that's for the actual procedure to be followed by the qualified welder). The procedure qual and resulting wps tells the welders what process to use, what gas, gas pressure, electrode classification, and much more. They will use that to qualify to as well as work to though you can have separate ones for the two operations. The different tables he mentioned will guide you as to what you can and can't do.
There is also a difference between a standard and a code. D1.1 and D1.3 are codes.
Now, before I stray too far, being the kind of equipment you mentioned it is quite possible that one of the D14.X codes applies instead. They follow D1.1 pretty close but not exactly.
So, having just scratched the surface, this is why more information is usually needed to give complete and accurate answers.
He Is In Control, Have a Great Day, Brent
Hello Weldenthu, if I have this right, you folks are an OEM and you don't have to comply with any specific welding codes or standards. If that is the case, I believe that you will not have any issues with the change in wire diameter.
If your welding call-outs are based on general welding engineering practices you will only need to concern yourself with meeting weld size conditions. In addition, considering whether the finished welds are without excessive or undue undercut or overlap/cold lap. I've based the aforementioned comment on using weld parameters where you might be a bit out of range for the welding based upon how you apply the smaller diameter wire, ie. possibly you plan on running a single pass 1/2" fillet or something of that nature and so you are running extra voltage and wire speed to hopefully make this happen. I realize that this example is out there and may not represent any of the conditions of your actual manufacturing practices nor have any application to your specific question. I'll be interested to hear more though, so please include a bit more information if you can. Good luck and Best regards, Allan