Electromagnetic Compression as Preforming Operation for Tubular Hydroforming Parts

Abstract

With the aim to extent the forming limits of tube hydroforming a concept of using a previous electromagnetic compression operation will be introduced. One important limit for the possibilities of tube hydroforming is set by the initial circumference and the maximum tangential strain of the used material, whereby the initial circumference is typically determined by the smallest local circumference of the workpiece. The application of an appropriate contoured preform makes it possible to use tubes with a larger initial circumference. In the paper the investigation of the suitability of electromagnetic tube compression for the production of such a preform will be presented. The valuation is based on geometric criteria and material properties of the resulting preform which are strongly influenced by the process parameters. The discussed aspects are the roundness of the preform and the strain hardening of the material.