Electrohydraulic Crimping of 316L Tube in a 316L Thick Ring

Abstract

During the electrohydraulic forming process a high current, up to one hundred of kilo amperes, is discharged between two electrodes immersed in a water tank. This creates plasma that generates a primary shock wave and secondary pressure waves. If these pressures are applied in a tube, it is then possible to deform dynamically this tube against a ring, leading to crimping. This process presents several advantages: it is possible to deform internally tubes of diameters ranging from a few millimetres to several centimetres, no lubrication is needed and because the process is dynamic, the spring back is limited and some materials can present an improved behaviour compared to quasi-static forming. In this paper, we present an original electrohydraulic crimping device. We successively present the operating principle of our system, the time evolution of the crimping pressure and the strain rate in the tube for two kinds of pulse shaper. Finally crimping tests are done to evaluate the efficiency of the process.