Union S 2 Si is a submerged arc (SAW) wire for mild steel. It is used in steel construction, on tanks, pipework and series production.
The wire works as a set with a matched flux, which decides the mechanical properties of the weld. The copper coated surface improves current pick-up in the contact tip and smooth feeding.
- Classification EN ISO: 14171-A S2Si
- AWS classification: A5.17 / SFA-5.17 EM12K
- Shielding: flux matched to the wire, no shielding gas
- Diameters: 2.0 / 2.4 / 3.0 / 3.2 / 4.0 mm
On heavier sections and in a cold workshop plan the preheating, so that the risk of cold cracking stays down. 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. Match the flux to this wire and check how dry it is, drying the flux decides the hydrogen level in the weld.
