We are using a 4330 V Modified, 17" diameter shaft that it is going to be welded (FCAW) with some A-514 steel ( low carbon ) pads on the surface, 5/8" thick with E81T1-Ni1M-JH4, 0.045 Diameter wire, 75/25 CO2, 3-4 passes typically required, (AWS A5.29-05)
C - 0.33
Mn - .47
Si - .19
Ni - 3.30...