Flange wrinkling in incremental shape rolling

Abstract. Automotive structural components from Advanced High Strength Steels (AHSS) can be manufactured with Flexible Roll Forming (FRF). Flange wrinkling is a common shape defect in FRF, this restricts the application of FRF in the automotive industry. The new Incremental Shape Rolling process (ISR) showed that a high tensile transverse strain is developed in the flange and that assists the plastic deformation in the flange. Hence, wrinkle severity can be significantly reduced when weight-optimized components are formed. In this study, the ISR process is applied to a variable width profile from DP600. This investigated profile is a modified automotive component. The forming strains and wrinkling severity in ISR are compared with those obtained from the FRF case. The ISR and the FRF experimental trials are performed on a prototype FRF facility and then used to validate the numerical models which are applied to analyse the deformation behaviour in both processes. The ISR results show a significant reduction in wrinkling. This is due to the high tensile transverse strain that is developed in the ISR flange which facilitates the plastic deformation and hence the flange is stably compressed to the required shape.