Joining of Sheets with Tubes by Electrohydraulic Forming

Electrohydraulic forming is a high-speed process, which is based on a force transmission by a working media. In this process, shock waves transmit the punching force in a very short period of time. These shock waves are applied to accelerate the workpiece towards a passive die. Besides forming and embossing of sheets and tubes, joining of sheets with tubes is enabled as a novel application presented in this contribution. Thereby, the tube is embedded temporarily in the die as a functional part. By accelerating the sheet towards the tube end, the joint is formed. This study deals with the question of how this joint is formed in sense of process kinematics and material flow. Therefore, the loading energy, the distance of sheet and tube as well as the sheet thickness was varied and the influence of these parameters and geometric conditions of the tube on the process and resulting joints was observed. Joining of EN AW-1050 aluminum alloy sheets to EN AW-6060 aluminum alloy tubes was performed. These joints were analyzed by microsections and head tension tests. The investigations introduce the new joining process regarding its process behavior and show first joining results.