Normally welding consumables manufacturers suggest the range of electrical parameters to be used during welding.
In the "specifications" page of the link you have provided you can see that it is suggested a certain voltage and a range of current.
Optimal welding parameters (not only electrical...
The main difference between these alloys is the allowable stress values, per ASME Section II, Part D;
Grade P22 has generally, at high temperature, an higher allowable stress compare with P12. In general you cannot simply substitute a pipe in grade P22 with an identical one in grade P12.
It's...
