TRIP assisted press hardened steel by the anisothermal bainitic ferrite transformation

Abstract A new steel chemical composition is combined with a press hardening process, in which die-quenching interrupted by opening the forming tool to permit slow cooling of hot formed part through anisothermal bainitic ferrite transformation. This promotes carbon partitioning austenite before re-closed and resumed near-ambient temperature. The final microstructure predominantly dispersions martensite up 11 % retained austenite. Retained can undergo stress induced transformation an automobile crash event. exhibits 25 elongation 930 MPa tensile strength. In contrast traditional cold formable Transformation Induced Plasticity assisted steels, where consumed during work forming, here, desired achieved after meaning more uniformly distributed within part, enhances energy absorption. carefully designed provide optimal microstructural evolution constraints yet relatively lean manufacturer friendly. process efficient as secondary heating not required since retarded provided residual heat accumulation newly developed titanium alloy tool. Development technology demonstrated experiments, testing, analysis, transversal & axial crush testing parts numerical simulation including modelling technique that accurately simulates deformation versus parts. Results show 22 increase absorption under crushing compared steels owing greater capacity radii are shown be exposed highest stresses crushing.