Press-hardening of high carbon low-density steels – POSTER

Votava Filip - University of West Bohemia in Pilsen (Czech Republic)

Sheets of experimental high carbon low-density steels (LDS) with a thickness of 1.7 mm were processed in a combined tool designed for press-hardening. Press-hardening, also known as hot stamping or hot press forming, is a manufacturing process used to create car body parts with exceptional mechanical properties and safety standards. These components often require tailored properties, meaning different mechanical characteristics in various parts of the compo-nent. LDS have a lower specific density than conventional steels, so their use would be particu-larly suitable in automotive applications. Combined tools are employed to achieve distinct me-chanical properties within a single part through thermomechanical processing. This results in the final part shape and simultaneous heat treatment, leading to high strength in one area of the sheet metal and high plasticity (ductility) in another. The hardened part provides collision strength, while the more ductile part absorbs kinetic energy and converts it into deformation energy. Three different high carbon LDS with differences in chemical composition were subject-ed to this experiment and the hardness, microstructure and mechanical properties for the two areas of each sheet were evaluated. The aim is to determine their suitability for processing by press-hardening and to try to achieve tailored properties (i.e. differences in ductility and strength across one part) as in a typical representative of 22MnB5 boron steel, where a strength limit of 1500 MPa at 5% ductility is achieved in the cooled part and 600 MPa at 15% in the heated part. Tailored properties were also achieved in LDS but with only relatively small differences between the two tool areas. The omega profiles were produced by press-hardening without any defects and it was possible to process the steels in the mentioned process without any difficul-ties.