Dissimilar Joints

It is sometimes necessary to join nickel alloys to other metals or alloys. It may also be required to join different nickel alloys together. Cleanliness is of prime importance when welding nickel alloys.

Welds between many nickel alloys and steel can be made with common welding processes using pure nickel or nickel-rich consumables. In some cases care needs to be taken to avoid excessive iron pick-up.

Welding nickel alloys to stainless steels may be achieved using suitable nickel alloy fillers and most common welding processes. Again excessive dilution from iron (and chromium) may need to be avoided.

Buttering cast iron with nickel prior to completing the joint with a nickel alloy filler is a technique that will work with most nickel alloys if they need to be welded to cast iron. The main problem is the inherent poor weldability of cast iron.

Welding nickel alloys to copper alloys may give problems due to copper pick-up by the nickel alloy but use of a technique whereby the copper is buttered first can overcome this problem.

Welding different nickel alloys together is usually not too difficult and appropriate nickel alloy fillers are used. Some nickel alloys, particularly Nimonic alloys, can be difficult to weld, and so dissimilar joints may well prove very difficult to make.

Welding nickel alloys to aluminium alloys by fusion techniques is not recommended. Complex procedures involving buttering and inserts may prove successful but non-fusion processes are more effective.