Dissimilar JointsIt is sometimes necessary to join cast iron to other metals or alloys. The main problem encountered whatever material is being joined to the cast iron is the very limited weldability of the cast iron. Welding cast iron to carbon steel or alloy steel may be carried out using nickel-rich filler metal. This will be compatible with both sides of the joint. Most arc welding processes are suitable for this combination of materials. Preheat is recommended for the cast iron and for the steel if it has a high carbon equivalent. To weld cast iron to stainless steel requires that the cast iron is first buttered with nickel-rich filler, the weld being completed using a suitable stainless steel filler. Welding cast iron to nickel alloys can be straightforward or difficult depending on the nickel alloy involved. Nickel alloy fillers are used, sometimes employing a buttering technique as for stainless steel before completing the weld with suitable nickel alloy fillers. Joining cast iron to copper alloys and aluminium alloys is rarely required and can be difficult.
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