Control over Mechanical Properties and Microstructure of BR1500HS Hot-stamped Parts

Abstract

The hot-stamping processing parameters are of critical importance in transforming ultra-high-strength steel (UHSS) into high-quality parts, which were studied by mechanical properties tests, metallographic observations and calculation analysis method based on hot stamping experiments and numerical simulation technology, the mechanical properties, thickness, dimensional accuracy, and microstructure of the hot-formed parts are analyzed to determine the influence of different processing parameters for UHSS parts formed from BRI500HS. The results indicate that the quenching time had the most significant impact on the mechanical properties of the parts, and longer quenching time resulted in better mechanical properties. In addition, the pressing speed had a significant influence on the thickness of the formed parts, and the part-opening temperature had the most significant effect on the dimensional accuracy of the parts. And to get hot-stamped parts with excellent quality, the optimum process conditions should be set as heating temperature of 930 °C, soaking time of 4 min, stamping force of 7 MPa, pressing speed of 75 mm/s, quenching time of 15 s, and water-flow rate of 1.1 m/s.