Reducing vehicle weight by tailoring the properties of hot stamped structures

乘用车的结构部件可以由冲压硬化超高强度钢(UHSS)制成，从而减轻其重量。然而，这要求这些结构具有量身定做的特性，以便在发生碰撞时，经过工程设计的“软”区域能够吸收撞击能量。通过控制零件不同区域的冷却速度，可以在烫印汽车结构中实现量身定制的性能。新等级的UHSS，如Usibor®2000，为使用这项技术减轻车辆重量提供了更大的潜力。然而，这种高强度零件的生产需要对其烫印后的力学性能和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Usibor®2000和Usibor®2000/Ductibor®1000拼焊板制造的直槽型材最终机械性能的影响。其次，先进的材料模型将被开发并应用到模拟代码中，以准确地预测具有定制特性的槽形截面在各种载荷条件下的变形行为。这项研究的主要成果之一将是一套数值工具，它将使我们的加拿大工业合作伙伴福特、马伍德和安赛乐米塔尔Dofasco能够准确地预测具有定制特性的Usibor®2000结构的耐撞性。这些数值工具将使他们能够在汽车结构中设计性能的最佳分布，从而充分利用超高速钢的轻量化潜力。这项研究预计将加强我们加拿大工业合作伙伴的竞争优势，并使他们能够保留加拿大的制造设施和就业机会。四到五名学生将接受热冲压结构性能剪裁科学和高级数值模型开发方面的培训。最终，该技术的工业化实施将有助于进一步降低车辆重量和能耗。

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.