Effect of Scale on Runout Table Heat Transfer

钢铁新产品开发继续成为经济社会的重要贡献者。钢铁发展步伐的加快主要是由汽车行业的需求推动的。在这里，先进的高强度钢在减轻车辆重量从而提高燃油经济性方面发挥着至关重要的作用，成为减少温室气体排放的关键因素。这些钢具有极具吸引力的性能，包括优异的强度-成形性平衡和耐撞性，这些性能是通过增加合金化加入量(如锰、硅)和严格的工艺控制获得的。热轧轧辊上的冷却路径起着至关重要的作用，因为它可以用来定制从面心立方(FCC)晶体结构的奥氏体到体心立方(BCC)晶体结构的铁素体的相变。具体地说，根据钢的化学成分和工艺，可以设计出由不同转变产物组成的复杂多相组织，这为性能设计提供了新的范例。特别是，在热轧含硅较高的钢材时，可能会形成持久的氧化皮，影响轧制台的冷却效率，导致不可接受的性能变化。因此，开发优化的Runout表处理策略以减轻规模的作用是很重要的。拟议的项目旨在增进关于结垢对热传递影响的基础知识。将进行专门的中试运行台测试，以量化取热率，并将采用先进的表征技术来确定结垢结构和化学成分。拟议中的项目是与加拿大领先的汽车钢板生产商安赛乐米塔尔Dofasco密切合作进行的，旨在为设计优化的冷却策略提供新的见解。该项目为博士生提供了培训机会，他们将通过将传热学研究与微观结构表征相结合来发展独特的技能水平。

The development of new steel products continues to be an important contributor in the economy and society. The increased pace of steel development is primarily driven by the demands of the automotive industry. Here, advanced high strength steels take a crucial role to reduce vehicle weight and thereby improving fuel economy as a critical aspect to decrease greenhouse gas emissions. These steels have attractive properties including superior strength-formability balance and crash worthiness that are obtained by increased alloying additions (e.g. Mn, Si) and stringent process control. The cooling path on the runout table in a hot mill takes a critical role as it can be used to tailor the phase transformation from austenite with a face-centred cubic (FCC) crystal structure to ferrite with a body-centred cubic (BCC) crystal structure. In detail, depending on steel chemistry and processing, complex multi-phase microstructures can be engineered consisting of different transformation products which offer new paradigms for the design of properties. In particular during hot rolling of steels with higher Si contents a persistent oxide scale may form that affects cooling efficiencies on the runout table leading to unacceptable property variations. Thus, it is important to develop optimized runout table processing strategies to mitigate the role of scale. The proposed project is designed to advance fundamental knowledge on the effect of scale on heat transfer. Dedicated pilot-scale runout table tests will be conducted to quantify heat extraction rates and advanced characterization techniques will be employed to determine scale structure and chemistry. The proposed project is conducted in close collaboration with ArcelorMittal Dofasco - Canada's leading producer of automotive steel sheets - and aims to provide new insight in designing optimized cooling strategies. The project offers training opportunities for a PhD student who will develop a unique skill level by combining heat transfer studies with microstructure characterization.