Unique Failures in Explosion Bond Cryogenic Transition Joints

In cryogenic process plants that use aluminum alloy brazed core exchangers, a transition to austenitic stainless steel piping is often required. Presently, multi-layered explosion bonded piping joints provide that joint. These joints employ multiple layers of different alloys (e.g. 304L SS, Ni 200, Ti, Al, and Al-Mg), to provide the required leak-tight joint. Analysis of a few recent failures of these joints have shown interesting properties on a micro scale within the nickel layer, adjacent to the titanium-nickel interface. This paper will discuss the morphology of cracks, and discuss potential causes.