INFLUENCE OF LOAD PATHS AND BAKE HARDENING CONDITIONS ON THE MECHANICAL PROPERTIES OF DUAL PHASE STEEL

摘要

In recent years high strength hot rolled dual phase (DP) steels became available. This multiphase steel type shows a strong Bake Hardening (BH) potential being of importance for shaping of body structures. Normally the BH effect is assessed using the uniaxial tension test In reality shaped parts show a variety of stress paths, starting from deep drawing over uniaxial, plane strain to biaxial conditions. This is the special aspect of the analysis in combination with BH conditions on the evolution of strength parameters DP steels samples were pre-strained under uniaxial, biaxial and plane strain conditions with different degrees of pre-strain. Subsequently, samples were undertaken a baking treatment at different temperatures. The mechanical properties were analysed particularly with regard to temperature and pre-strain. Pre-straining the samples with defined degrees of deformation and a subsequent aging treatment leads to enhanced material's strengthening.