AA5052 tube to SS304L tube sheet/end plug joining by magnetic pulse welding

The components/assemblies used in the reactor should have low thermal neutron absorption cross section. For this purpose, Zr and Al based material are preferable as their thermal neutron absorption cross-section is lower than other available structural material. These materials also have sufficient strength and low induced activity. The out of core components/assemblies and piping etc. are made up of steel material as it has lesser cost, easy availability and fabrication. The joining of AA-SS material is beneficial because it will allow to use aluminium material for in core components and steel material for out of core components. In APPD two different type of joints between AA5052 tube to SS304L end sheet/end plug have been developed by Magnetic Pulse Welding (MPW) technique that have high potential of application in research reactor. MPW is a well-established technology under the branch of solid-state joining processes. Joining dissimilar metals like AA and SS by fusion welding faces a lot of hardship due to its wide variation in physical properties. In MPW, there is no application of heat to melt the base metal and jet formed during the process clean the two mating surfaces. Special tool coils, fixtures have been designed for this application. Experiments were conducted on available MPW machine at APPD. These both type of joints are at various stages of destructive and NDT qualifications. (author)