Reducing vehicle weight by tailoring the properties of hot stamped structures

用高压硬化超高强度钢（UHSS）制造乘用车的结构部件，可以减轻乘用车的重量。然而，这要求这些结构具有定制的性能，以便设计的“软”区域能够在碰撞事件中吸收冲击能量。通过控制零件不同区域的冷却速度，可以在热冲压汽车结构中实现定制的性能。新等级的UHSS，如Usibor®2000，使用该技术提供了更大的潜力来减轻车辆重量。然而，这种高强度零件的生产需要对其热冲压后的力学和显微组织性能进行全面的研究。本研究的第一个目标是确定局部模内冷却对由Usibor®2000和Usibor®2000/Ductibor®1000定制焊接板制成的直道截面的最终机械性能的影响。其次，将开发先进的材料模型并将其实现到仿真代码中，以准确预测具有定制属性的沟道截面在各种加载条件下的变形行为。

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.