Prediction and inline compensation of springback in roll forming of high and ultra-high strength steels

With the rising interest in lightweight construction, the usage of high and ultra-high strength steels has increased remarkably during the last years. Unfortunately, these steel grades show more springback than mild steels do, which leads in consequence to lower dimensional accuracy. To improve the bended part’s geometry considerable trial-and-error work is necessary since the influence of different bending-parameters (e.g. the bending radius, sheet thickness, yield strength, Young’s modulus, the material’s strain hardening coefficient, …) on the amount of springback is still unknown. The aim of the paper at hand is therefore the investigation of springback for different parameter combinations. Furthermore, an online calibration system for occurring springback during roll forming is presented to compensate springback independent of material or process parameters.