High strength trip/twip steels for crash resistance of structural car body parts

摘要

Recent trends in the automotive industry towards improved safety standards and reduced weight car bodies as well as a more rational and cost effective manufacturing have led to great interest in high strength and "supper" tough steels. The newly developed light weight austenitic high manganese TRIP (transformation induced plasticity) / TWIP (twinning induced plasticity) - steels with certain amounts of aluminium and silicon exhibit high flow stress (600 to 1100MPa), extremely large elongations (60 to 95percent) and an extraordinary specific impact energy (0,4 to 0,5Jmm~(-3)) even at crash-like strain rates of about 10~2 to 10~3 s~(-1). High manganese steels with excellent formability, such as deep drawing and stretch forming operations at high strain rates exhibit an extraordinary shock resistance and impact strength for axial, side and off-set impact loading in car crash situations. The high strength properties of these low cost steels and the reduced specific weight lead to an overall weight reduction of the car bodies of about 15 to 25percent.