316L (including ER316LSi) filler metal should be used with 316L and 316 base metals. CF-8M and CF-3M are the cast equivalents of 316 and 316L, respectively.

Use 309L (including ER309LSi) when joining mild steel or low alloy steel to stainless steels, for joining dissimilar stainless steels such as 409 to itself or to 304L stainless, as well as for joining 309 base metal. CG-12 is the cast equivalent of 309. Some 308L applications may be substituted with 309L filler metal, but 316L or 316 applications generally require molybdenum and 309L contains no molybdenum.

Per D15.1 we use 309L FCAW to join A36 to Manganese. FCAW wire process is less crack resistance to bare 309L. Fixed a lot of issues.

309L Flux core .045 - 10.50 per/lb. 312L $$$ - 316L $$$$.

I need info for a Prequalified WPS or a work around so I don't have to spend a month qualifying welders. the PQR is just for records purposes. i can do the PQR just trying to save time. I know D1.6 clause 4.7.5 States:

"With the approval of the engineer
performance qualification test coupon may be with any of Group I or
II of AWS D1.1. Qualification with any one of those materials shall be
considered as qualification to weld any material permitted in this code."

So I am thinking I can get engineering to sign off on my FCAW D1.1 welders to join the materials without have to retest and qualify all my guys. We are using the E309LSI and E316LSI. The specified code is which ever is applicable. D1.1 for the carbon and D1.6 for the stainless.