Flash~R Bainite: Cold Stampable 1500-MPa Sheet Metal for B-Pillars

摘要

Flash~R Bainite Processing employs rapid thermal cycling (<10s) to strengthen commercial off the shelf (COTS) steel sheet, plate, and tubing into AHSS. In a continuous process, induction technology heats a narrow segment of the cross section in just seconds to atypically high temperatures (1000-1300°C ). Quenching substantially immediately follows. Flash? Processing optimizes the inherent heterogeneity of steelmaking to create a multi-chemistry, complex mixture of 20% bainite and 80% martensite. Carbon migration and carbide dissolution are controlled by limiting time in the austenitic range. Unlike conventional quench and temper processes, chemical homogeneity is intentionally avoided. The leanest prior ferritic regions transform to bainite while prior pearlite forms martensite upon Flashing. Such a 20/80 mixture is known to have 7-10% higher yield/tensile strength than fully martensite with the beneficial ductility of the bainite constituent. Dozens of COTS steels have been Flashed and evaluated. Flashing steel such as AISI1010 (1100MPa UTS) and AISI1020 (1500MPa UTS) has shown unprecedented room temperature stamp-ability. Flash~R 1100 has fully folded to a 0T bend radius upon itself with no springback. Flash~R 1500 has been stamped at room temp to form many difficult shapes to include B-pillars and complex seating components. Compared to leading boron steels, Flash? tubing has ~15% higher resisting force and -20% more energy absorption during NCAP crash/impact simulation. The 1500MPa form-ability desired of 3G-AHSS is now achievable. OEMs/Tierls predict simultaneous weight and cost savings. Flash~R Bainite Processing is the proven method to achieve elemental heterogeneity, the New Frontier in Steel.