Process compatibility and damage performance of carbide-free bainite advanced high strength steel (AHSS) sheets**

为了减轻车辆重量（提高燃油经济性/降低排放）和抗碰撞（提高被动安全性），人们正在大力研究开发先进的高强度钢（AHSS）。这导致了一些第三代（3G）钢的发展。虽然一些最新的3G钢已经在实验室规模上证明了所需的性能，但商业生产这些等级的最佳热机械加工要求超出了目前加拿大工厂的能力。此外，升级生产设施的高资本成本可能促使全球钢铁制造商将这些关键的高附加值产品的生产集中在加拿大以外的地方。为了降低这种风险，麦克马斯特大学和CanmetMATERIALS将研究一种特定类别的贝氏体钢的加工和性能，这种钢适用于安赛乐米塔尔位于安大略省汉密尔顿的工厂现有的连续镀锌线（CGL）。目标性能是抗拉强度超过1150MPa，总伸长率接近20%，这大大超过了目前加拿大钢厂生产的AHSS商业产品的性能（例如780和980MPa等级）。此外，冲压复杂的车身结构件需要延展性以改善成形响应（例如拉伸法兰性）。所提出的循环流化床薄板的损伤性能尚未得到充分的研究，这类AHSS的微结构-损伤性能之间的相互作用仍有待确定（知识缺口）。**本研究的主要目标有两个：(a)根据ArcelorMittal Dofasco ON Hamilton工厂现有设备的能力和局限性，定制无碳化物贝氏体AHSS板的合金成分和加工参数，并了解控制无碳化物贝氏体板强度和损伤性能的微观组织因素。(b)培养一名博士生，使其有独特的机会处理从合金设计到工艺优化和产品评估的整个产品开发过程，同时接触CanmetMATERIALS的中试规模设施和麦克马斯特大学的学术研究环境

Intense research efforts are being expended on developing advanced high strength steels (AHSS) for vehicle weight reduction (improved fuel economy/lower emissions) and crash resistance (improved passive safety). This has resulted in the development of a number of Third Generation (3G) steels. Although some of the newest 3G steels have demonstrated the required properties at the lab scale, the optimum thermomechanical processing requirements to commercially produce these grades are beyond current Canadian plant capabilities. Further, the high capital costs of upgrading production facilities may induce global steel manufacturers to concentrate production of these critical high value-added products in locations outside Canada. In order to mitigate this risk, McMaster University and CanmetMATERIALS will investigate the processing and performance of a specific class of bainitic steels that are suitable for processing on existing continuous galvanizing lines (CGL) at ArcelorMittal Dofasco's facilities in Hamilton, ON. The target performance is tensile strength of more than 1150MPa with total elongation approaching 20%, which significantly surpasses the properties of current AHSS commercial products made by steel plants in Canada (e.g. 780 and 980MPa grades). Further, ductility for improved forming response (e.g. stretch flangeability) is required to stamp complex autobody structural parts. The damage performance of the proposed CFB sheets has not been studied adequately and the interplay between microstructure-damage properties of this class of AHSS remains to be determined (knowledge gap). **The main objectives of this research are twofold: (a) Tailor alloy composition and processing parameters of carbide-free bainitic AHSS sheets to the capabilities and limitations of existing facilities at ArcelorMittal Dofasco's Hamilton, ON, plant, and understand the microstructural factors controlling the strength and damage performance of carbide-free bainitic sheets. (b) Train a Ph.D. student with a unique opportunity to tackle the entire span of product development, ranging from alloy design to process optimization and product assessments while exposed to both pilot-scale facilities of CanmetMATERIALS and academic research environment of McMaster University.**