Union S 2 Ni 3,5 is a low-alloy, cryogenic submerged arc (SAW) wire for low-temperature nickel steels. It is used on liquefied gas tanks, cryogenic installations and refrigeration equipment.
The wire is used on mechanised stations, on butt welds in plate and circumferential welds on tanks, and its copper coated surface improves current pick-up in the contact tip. The deposit keeps its impact toughness in the cryogenic range.
- Classification EN ISO: 14171-A S2Ni3
- AWS classification: A5.23 / SFA-5.23 ENi3
- Shielding: flux matched to the wire, no shielding gas
- Diameters: 2.4 / 3.0 / 3.2 / 4.0 mm
Keep the heat input and the interpass temperature down, low temperature toughness drops as soon as the joint overheats. Keep an even flux layer over the arc, too thin a layer exposes the arc and too thick a one spoils the bead shape. Watch the wire stick-out and the position of the head against the weld centre line, under a flux you cannot see the pool and a mistake shows only after the slag is chipped off.
