Dissimilar JointsIt is sometimes necessary to join copper to other metals or alloys. It may also be necessary to join dissimilar copper alloys together. Fusion welding of brass and leaded alloys is not really recommended due to the low melting point alloying additions either boiling off or migrating to give cracking. Welding other copper alloys to carbon steel, alloy steel, or stainless steel, can be achieved directly using aluminium bronze filler metals but the weld has a complex metallurgy and may not always be suitable. A procedure involving buttering of the steel, the copper alloy, or both, may also be used. Copper to cast iron is not a normal combination but if required buttering the cast iron with nickel before completing the weld with nickel alloy filler may be used. Welding different copper alloys together may be able to be carried out directly with suitable fillers but may require one side of the joint to be buttered first depending on the alloy combination. The procedure adopted to weld copper alloys to nickel alloys depends on the two alloys involved, nickel alloy filler is normally used and a buttering technique may be necessary to avoid migration of some elements. Welding copper alloys to aluminium alloys by fusion processes is not recommended but satisfactory welds can be achieved using friction or other non-fusion techniques.
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