Dissimilar Metal Joining

Abstract

Magnetic pulse welding (MPW) can offer unique advantages over other joining techniques when applied correctly. Especially for dissimilar metal welding it has several advantages due to its very low heat input and short process times. Due to the high demands of the process on the welding system properties, it is vital to understand the process as detailed as possible to reduce system-related challenges and costs. The paper discusses similarities and dissimilarities to other high velocity joining processes like explosion welding. Specific aspects of MPW, like its special transient nature are presented and their impact on welding parameters are explained. Using results of example welds on similar and dissimilar metal joints, microscopic and macroscopic effects of part geometry, metallurgical behaviour and pulse parameters are shown. Concerning microscopic effects, the question is discussed whether interfaces of dissimilar metals can fully be free of intermetallics. This is a relevant question in relation to achievable joint strength, joint ductility and even electric conductivity. Here evidence of recent SEM and TEM analysis is presented. Conclusions are drawn with respect to optimal process conditions and practical geometric relations on the macroscopic scale.