Hot Stamping and Blank Designing for a Vehicle Bumper Using Ultra High Strength Steel (UHSS)

Full-scaled hot stamping dies were designed for a vehicle bumper, based on evaluation of cooling system by FE simulation and the temperature variation assessment by analytical model. The blank shape was gained using inverse algorithm and well-designed according to production practice. Experiments were conducted to verify the reliability of both the die and blank design, as well as tests for microstructure and mechanical properties of the hot-stamped part. Results show that, CAE analysis provides a robust support for hot stamping die and blank design; Position stability of hot blank is greatly improved during robotic transport process after shape designing; Metallographic analysis demonstrates the hot-stamped bumper obtained a fully martensitic microstructure, its tensile strength is about 1550 MPa, microhardness is 47.5 HRC, and the elongation is up to 6%.