In submerged arc welding the properties of the joint are decided by the wire and flux pairing, not by the wire alone. The same Union S 2 wire with a basic agglomerated flux will give a different impact toughness than with a fused flux. That is why the manufacturer classifies the combination to EN ISO 14171, for example S 46 4 FB S2Si, rather than the wire alone.
Fluxes are chosen for the job. Basic fluxes give the best impact toughness at low temperatures and are used on pressure vessels. Rutile and fused fluxes lift more easily and give a smoother face in fast multi-run welding. Flux has to be dried as the instructions state, usually 300 to 350 degrees Celsius for 2 hours, because damp flux means porosity and hydrogen cracking.
You match the wire diameter to the current and the thickness. A 2.0 mm wire works at 250 to 450 A, 3.0 mm at 350 to 600 A, 4.0 mm at 450 to 800 A, 5.0 mm above 600 A. On a single pass in heavier material the heat input matters, because too much of it coarsens the grain in the heat affected zone.
Pay attention to the wire stickout from the contact tip. A longer stickout raises the deposition rate through resistive preheating, but it reduces penetration.
For wear-resistant and corrosion-resistant overlays, wires from the WEARcore line in the SAW version are used. When ordering, give us the material, the thickness and the acceptance requirements, and we will select the wire and flux together.