DCSP or AC
Filler metal ER CuNiAl
Argon, Helium,or a mixture
Preheat not to exceed 300DegF
Electrode would be dependent upon current/polarity.
AC with Argon provides best cleaning. Better penetration and higer travel speeds with DCSP.
Source Welding Handbook, Volume three, Eighth edition, Page 192/193.
Have a nice day and good holiday
Gerald Austin
http://www.weldinginspectionsvcs.com
Iuka,Miss