Abstract
Formable 980–1470 MPa grade ultra high-strength TRIP-aided sheet steels with bainitic ferrite matrix (TBF steels) have been developed for cold forming of automotive applications. Complex additions of 1.0%Al–0.05%Nb–0.2%Mo to 0.2%C–1.5%Si–1.5%Mn base steel increased both the volume fraction and carbon concentration of retained austenite films of the TBF steel, with refining of microstructure. Extremely much retained austenite was realized in the TBF steel austempered at 450–500°C, corresponding to hot-dip galvanization just after annealing. Good combinations of strength and elongation and strength and stretch-flangeability were achieved when the TBF steel was austempered at 450–500°C and 425–475°C, respectively. These good combinations were caused by fine lath structure and a large amount of metastable retained austenite film. It is noteworthy that the TBF steel exhibited an excellent combination of total elongation and stretch-flangeability when austempered at 325–350°C lower than MS.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
