Effect of Bending Variables on the Characteristics of EN-AW5018 Tubes for Subsequent Hydroforming

Understanding the effects of forming history on the subsequent hydroformability of aluminum alloy tubes is critical for widespread acceptance of aluminum as a light-weight alternative in automotive components. The aim of this research is to investigate the influence of pre-bending on the characteristics of aluminum alloy tubes for the hydroforming process. Tube bending experiments were performed on 2 and 3.5 mm wall thicknesses with 76.2 mm outer diameter EN-AW5018 tube. In the tube bending experiments, key process parameters such as boost were varied and the effect on the resultant thinning, strains and springback of the as-bent tubes was assessed. Bending boost is shown to reduce thinning and strains in the as-bent tubes which has been found to be favourable for any subsequent hydroforming operation.