Electrode having a nickel core wire, for welding on grey cast iron with and without preheating. Suitable for welding joints as well as for surfacing of worn cast iron parts. Suitable to use in repair of machine frames, machine housings, machine parts and bearing blocks. The electrode has a very soft, regular fusion, and a quiet and steady arc. It is well suited for positional welding. Very little dilution with the parent metal takes place, resulting in good machinability of the transition area. Weld short beads, about 30 to 50 mm long. In order to reduce weld residual stresses, hammer-peen welds slightly before cooling. Preferably is used with DCEN but possible to use with also AC.