Bimetal

This product, composed of a nickel and iron base with a bimetal core, is designed for welding and repairing cast iron. It is ideal when high-quality deposits and excellent mechanical characteristics are required, combined with a superior aesthetic. The high nickel content gives the deposit remarkable toughness. It is also suitable for joining cast iron to steel in various applications. Main applications include repairing and maintaining machine tool bases, engine blocks, restoring defects in castings, pumps, cylinders, and pistons. To avoid cracks, it is advisable to make small beads and peen the deposit, which has excellent crack resistance while remaining easily machinable. Even during restoration operations, follow similar procedures to optimize weld quality.

Electrode with basic-graphite coating with bimetallic core in Fe-Ni.

The structure depends on the chemical composition and the speed of solidification and subsequent cooling down.

Particularly suitable for cold welding of all types of cast iron, in particular spheroidal, white and black cast iron and malleable cast iron, and for joining cast iron with steel.

To prepare the welding area, remove the fusion crust using techniques such as machining, grinding, or chiseling. During the repair of casting defects, ensure all traces of defective metal are removed from the base metal. It is essential to eliminate grease, oil, dirt, or other contaminants using suitable solvents. If the casting is impregnated with oily substances, heat the affected area to facilitate volatilization; generally, 400 °C is sufficient. In case of heavy contamination, heat quickly and briefly to about 540 °C to evaporate the grease. Although preheating is not always necessary, it is commonly applied. Preheat to a temperature between 200 °C and 350 °C and ensure gradual post-weld cooling. Maintaining an interpass temperature between 350 °C and 450 °C is crucial to prevent cracking. For large castings, intermittent welds can improve heat distribution, keeping the casting warm to the touch but preventing excessive overheating.