Thermanit 625 is a submerged arc (SAW) wire for welding nickel alloys. It is used on chemical process equipment, high temperature installations and mixed joints between nickel alloys and steels.
The wire joins grades such as NiCr22Mo9Nb, NiCr21Mo, NiCr15Fe, 1.4583, 1.4876, 1.4529 and NiCr21Mo6Cu, along with related materials. Its deposit keeps its impact toughness down to cryogenic temperatures, so it reaches tanks and lines for liquefied gases.
- Classification EN ISO: S Ni 6625 (NiCr22Mo9Nb)
- AWS classification: ERNiCrMo-3
- Shielding: flux matched to the wire, no shielding gas
- Diameters: 1.6 / 2.0 / 2.4 mm
Degrease the joint before welding, because sulphur and lead residues left after machining cause hot cracking in nickel. 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.
