Effects of Retained Austenite on Hydrogen Embrittlement in TRIP-aided Bainitic Ferrite Steel Sheet

In order to suppress global warming, it is necessary reduce the weight of autobodies, whereas improvement collision safety automobiles required which results in a increase. Research and development high-strength steel sheets for autobodies are being carried out achieve both two objectives. Among various sheets, low alloy steels utilizing transformation-induced plasticity retained austenite (TRIP-aided steels) have attracted attention as body frame automotive parts materials because their high strength ductility. However, there concern about hydrogen embrittlement TRIP-aided with tensile exceeding 1000 MPa, conventional steels. this study, reveal role on bainitic ferrite (TBF steel), (i) several TBF different volume fraction carbon concentration were prepared by austempering original sheet durations, (ii) slow strain rate technique tests hydrogen-charged uncharged test pieces together microstructure observations X-ray diffractions. It was revealed that became suppressed increasing time, attributable increase surface area lath and/or filmy metastable acting trapping site hydrogen.