Further processing of ultrafine-grain materials

Linear flow splitting enables the production of bifurcated profiles out of sheet metal. Included in the Collaborative Research Centre (SFB) 666 the new roll forming procedure uses obtuse angled splitting rolls and supporting rolls to increase the surface of the band edge. High hydrostatic stresses in the deformed zone lead to an elevated formability of the high strength steel ZStE 500. As a result of the process, the flanges consist partially of an UltraFine-Grain microstructure (UFG). Produced parts are characterized by increased stiffness and high surface hardness. The new structure influences the formability in an extensive way. The investigations presented in this paper discuss the further processing of the flanges from linear flow split profiles. Therefore three point bending tests and roll forming experiments are carried out. A finite element analysis to characterize the damage is set up as well.