Ultra High-Strength Low-Alloy TRIP-Aided Sheet Steels with Bainitic Ferrite Matrix

摘要

The transformation-induced plasticity (TRIP) of retained austenite is very useful to enhance formability of high-strength sheet steels. Thus, three kinds of low alloy TRIP-aided steels with different matrix structure and different retained austenite morphology have been developed for weight reduction and impact safety performance of vehicles up to now. The conventional TRIP-aided steels composing of polygonal ferrite matrix and blocky retained austenite islands (hereafter called PF steel) possessed and an excellent stretch-formability and deep drawability. However, the PF steel has been applied to only some impact members due to a lack of stretch-flange formability and bendability.