Electrode having a pure nickel core wire for welding cast iron without or with low preheating (max. +300˚C). For repair welding of cracked cast iron parts or joining components made of steel, copper or nickel materials to castings. Electrode suited to welding cast iron with lamellar graphite, white and black heart malleable and nodular cast iron. Easy arc striking and restriking, stable arc, smooth bead surface. Weld short beads, about 30 to 50 mm long. In order to reduce weld residual stresses, hammer-peen welds slightly before cooling. Weld metal is machinable. Preferably used with DCEP but possible to use also with AC.