Dissimilar Joints with Carbon SteelIn industry today carbon steels are frequently welded to alloy steels, stainless steels, nickel alloys, and cast irons. Less frequently there is a need to weld carbon steel to copper alloys or aluminium alloys. Welding carbon steel to alloy steel, stainless steel, and nickel alloys can be carried out using most welding processes. The consumable used for fusion welding to alloy steel must be compatible with both steels. Preheat may be necessary depending on carbon equivalents. Welding to stainless steels usually requires the use of specially formulated Cr-Ni-Mo or nickel alloy consumables to maintain a suitable, crack-free weld metal microstructure. Preheat may also be necessary. Nickel alloy consumables are recommended to fusion weld steel to nickel alloys, the choice of which to use depending on the nickel alloy involved. When welding steel to cast iron a nickel alloy consumable is used but the main problem is the low ductility and poor weldability of the cast iron. Welding to copper and some alloys by friction welding or other non-fusion techniques such as brazing and soldering produces good results. Fusion welding is difficult and specialist techniques may be needed to produce joints with the required mechanical properties. Fusion techniques are not recommended to weld steel to aluminium alloys. Friction and other non-fusion techniques are preferred.
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