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

目前正在大力研究开发先进的高强度钢（AHSS），以减轻车辆重量（提高燃油经济性/降低排放）和耐碰撞性（提高被动安全性）。这导致了许多第三代（3G）钢的开发。 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会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。为了降低这一风险，麦克马斯特大学和CanmetMATERIALS将研究适合在位于安大略省汉密尔顿的ArcelorMittal Dofasco工厂现有连续镀锌线（CGL）上加工的特定类别贝氏体钢的加工和性能。目标性能是抗拉强度超过1150 MPa，总伸长率接近20%，其显著超过了目前由加拿大钢铁厂制造的AHSS商业产品（例如780和980 MPa等级）的性能。此外，冲压复杂的车身结构部件需要用于改善成形响应（例如拉伸凸缘）的延展性。所提出的CFB板的损伤性能尚未得到充分研究，这类AHSS的微观结构-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方面：（a）调整合金成分和工艺参数的无碳化物贝氏体AHSS板的能力和现有的设施在ArcelorMittal的汉密尔顿，ON，工厂的限制，并了解控制的强度和损伤性能的无碳化物贝氏体板的微观结构因素。(b)培养博士学生有一个独特的机会来解决整个产品开发的跨度，从合金设计到工艺优化和产品评估，同时接触到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.