Influence of the forming process on springback

Abstract

Abstract The use of advanced high-strength steels (AHSS) is associated with increased springback and represents a great challenge for today’s press shops with regard to the dimensional accuracy of cold-formed sheet metal parts. Springback, its appearance and characteristics are mainly dependent on the stress state introduced by the forming process and part geometry before opening the tools. With the aim of determining the influence of the forming process on springback, sheet metal forming simulation is used in this contribution to analyze a hat profile from a high-strength dual-phase steel (DH1000) by three different forming processes: crash forming, bending and drawing. For this purpose, the stresses generated by these processes and resulting springback are examined considering the respective forming history. The results show the strong influence of the material flow controlled by the process and tool geometry on the stress state before springback, which leads to significant differences in the springback of the hat profile among the forming processes: springback increases from crash forming to bending and drawing.