Get experience sub-contractor to do the job

Joey makes a good point. Given the question you are asking it would be my assessment as well that you are not prepared to properly handle such a material. You are dealing with what is called a super duplex and there are parameters that are absolutely critical and quite narrow in order to be successful. And it takes experience and full knowledge of their implications.

rolled alloys has some decent information if you can find it.  I know that GTAW is prob the best manual process for welding it becuase of the lower heat input.  Purging is a must, welds quite nice.  I dont some FCAW-G on it.  We found that for the Purge we used 98% argon 2% Nitrogen, and same for the shielding with GTAW.  With FCAW-G I dont remember what gas we used, but the wire we got from ESAB.