Magnetic Pulse Welding of Dissimilar Materials: Weldability Window for AA6082-T6 / HC420LA Stacks

Magnetic Pulse Welding (MPW) is a promising solid-state joining process that utilizes electromagnetic forces to create high-speed, impact-like collisions between two metal components. This welding technique is widely known for its ability to join dissimilar metals, including aluminium, steel, and copper, without the need for additional filler materials or fluxes. MPW offers several advantages, such as minimal heat input, no distortion or warping, and excellent joint strength and integrity. The process is highly efficient, with welding times typically ranging from microseconds to milliseconds, making it suitable for high-volume production applications, in sectors including automotive, aerospace, electronics, and various other industries where strong and reliable joints are required. It provides a cost-effective solution for joining lightweight materials, reducing weight and improving fuel efficiency in transportation systems. This contribution concerns an application for the automotive sector (Body In White) and in particular the welding of aluminium alloy and cold-rolled micro alloyed steels. One of the main aspect for MWP optimization is the determination of the process window that does not depend on the equipment used but rather on the parameters associated with the physical mechanisms of the process. It is demonstrated that process windows based on contact angle versus output voltage diagrams can be of interest for production use for a given component. The process windows based on the impact pressures versus the impact velocity for different impact angles, in addition to not depending on the equipment, allows to highlight other factors such as the pressure welding threshold for different temperatures in the impact zone, critical transition speeds for a straight or wavy interface, or for the jetting / no jetting effect. To determine these three impact parameters, relationships based on Buckingham's π theorem are a viable solution closed to reality. In addition, shear tests to determine the cohesion of the welded part were carried out. This allowed to add the mechanical resistance isovalues to the process window.