Welding Cast Iron

Cast iron is an alloy of iron with a carbon content of 2-5%, silicon content of 1-3% and upto 1 % manganese. The major types of cast iron are

Grey cast iron
Nodular cast iron
Malleable cast iron
White cast iron

Cast iron has very low ductility, low strength and is very brittle. It is generally alloyed or heat-treated for improving these properties.
 
The high carbon content adversely affects the weldability of cast iron. Out of the grades mentioned above, white cast iron is considered unweldable for all practical purposes. The other types can be welded successfully with the consumables available.