Run-out table bottom jet cooling

在过去的几十年中，先进钢有了巨大的发展，为包括汽车、能源和建筑在内的广泛应用提供了具有改进性能的钢产品。钢铁制造商的这些进步主要得益于创新工艺路线的设计和更好的过程控制。在这方面，过程模型的发展产生了重大影响。对于热轧钢，在输出台上喷水冷却是一种关键的冶金工具，可以定制钢的性能。在冷却期间，发生从具有面心立方（FCC）晶体结构的奥氏体到具有体心立方（BCC）晶体结构的铁素体的相变。具体而言，根据钢的化学成分和加工路径，可以获得不同的转变产物，以创建复杂的多相微观结构，为性能设计提供新的范例。为了实现这一潜力，关键是精确控制冷却路径，因为这决定了相变动力学和所得的微观结构。热运动钢板的水冷却是一个复杂的瞬态传热问题，包括核态沸腾、过渡态沸腾和膜态沸腾。目前的输出工作台冷却模型在很大程度上是经验性的。有必要开发更基本的模型。到目前为止，这一领域的研究一直强调顶部表面冷却，而底部射流冷却研究受到的关注要少得多。因此，拟议的项目旨在提供一个系统的底部射流冷却研究，以开发一个底部射流的冷却模型，严格占基本沸腾机制。该项目是与ArcelorMittal Dofasco合作进行的，ArcelorMittal Dofasco是加拿大汽车钢板生产的领导者。实验研究将在一个中试规模的跳动表设施进行，为模型开发提供指导。建议的传热相关性，然后将被纳入现有的热带钢轧机工艺模型的ArcelorMittalDofasco，使该模型可以验证与工业数据。该项目为三名研究生提供了培训机会。

There has been a tremendous development of advanced steels over the past few decades to provide steel products with improved properties for a wide range of applications including automotive, energy and construction. These advancements by steelmakers were critically enabled by design of innovative processing paths and better process control. Here, the development of process models has had a significant impact. For hot rolled steels cooling by water sprays on the run-out table is a key metallurgical tool to tailor the properties of the steel. During the cooling the phase transformation occurs 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 path, different transformation products can be obtained to create complex multi-phase microstructures which offer new paradigms for the design of properties. To realize this potential it is critical to control the cooling path precisely as this determines the phase transformation kinetics and the resulting microstructures. Cooling of hot moving steel sheets by water is a complex transient heat transfer problem including nucleate, transition and film boiling regimes. Current run-out table cooling models are to a large degree empirical in nature. There is a need to develop more fundamentally based models. Research in this area has so far emphasized top surface cooling whereas bottom jet cooling studies have received far less attention. Thus, the proposed project is designed to provide a systematic bottom jet cooling study to develop a cooling model for bottom jets that rigorously accounts for the underlying boiling mechanisms. The project is conducted in collaboration with ArcelorMittal Dofasco - Canada's leader in the production of automotive steel sheets. Experimental studies will be carried on a pilot scale run-out table facility to provide guidance for the model development. The proposed heat transfer correlations will then be incorporated into an existing hot strip mill process model of ArcelorMittal Dofasco such that the model can be validated with industrial data. The project offers training opportunities for three graduate students.