Reducing vehicle weight by tailoring the properties of hot stamped structures

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The weight of passenger vehicles can be reduced by making their structural parts from press-hardened ultra high strength steel (UHSS). This requires, however, that these structures be produced with tailored properties so that engineered "soft" zones can absorb the impact energy in the event of a collision. Tailored properties can be achieved in hot stamped automotive structures by controlling the cooling rate in different regions of the part. New grades of UHSS, such as Usibor®2000, offer even greater potential to reduce vehicle weight using this technology. However, the production of such high strength parts requires a comprehensive study of their mechanical and microstructural properties after hot stamping. The first objective of this research is to determine the effect of the local in-die cooling on final mechanical properties of straight channel sections made from Usibor®2000, and from Usibor®2000/Ductibor®1000 tailor-welded blanks. Secondly, advanced material models will be developed and implemented into simulation codes to accurately predict the behavior of channel sections with tailored properties as they are deformed under various loading conditions.One of the main outcomes of this research will be a set of numerical tools that will enable our Canadian industrial partners, Ford, Marwood and ArcelorMittal Dofasco to accurately predict the crashworthiness of Usibor®2000 structures with tailored properties. These numerical tools will enable them to design the optimum distribution of properties in automotive structures so as to take full advantage of the weight saving potential of UHSS. This research is expected to strengthen the competitive advantage of our Canadian industrial partners, and enable them to retain manufacturing facilities and jobs in Canada. Four or five students will be trained in the science of tailoring the properties of hot-stamped structures and in the development of advanced numerical models. Ultimately, the industrial implementation of this technology will help to further reduce vehicle weight and energy consumption.