Development of a bench-scale liquid metal wiping pilot system for understanding and optimizing the jet wiping process during hot dip galvanizing

开发小型液态金属擦拭试点系统，用于了解和优化热浸镀锌过程中的喷射擦拭过程

• 批准号: 565310-2021
• 负责人: Chattopadhyay, Kinnor
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=722200
• 关键词: Development; bench; scale; liquid; metal

In the case of hot-dip galvanizing, a continuously-moving steel strip is coated with a thin layer of zinc in orderto resist to oxidization. The protective metal is applied in its liquid state, by dipping the substrate into a bath ofcoating. However, at common strip speeds, the liquid layer dragged by the moving web is far too thick anduneven for the applications considered. The final coating thickness is therefore controlled by an air knife,which impinges a two-dimensional high-speed gas jet on the liquid layer. The forces imposed in the liquid bythe air knife jet results in the formation of a runback flow down to the bath, leaving a more uniform andconstant coating thickness dowsntream on the substrate. Nevertheless, operational constraints and processparameter variation can still result in significant coating non-uniformity and excess zinc consumption. Thisresearch program will focus on developing a bench scale galvanizing pilot where a low melting point liquidmetal will be used as an analogue to zinc and a rotating belt arrangement will be combined with an air knife tovisualize the jet wiping process in more detail. State of the art imaging techniques developed at the applicant'slaboratory will be used to visualize the wiping process, coating waviness and solution strategies will beproposed for optimizing the wiping system in terms of process parameters and air knife design. With manyexisting problems at the hot dip galvanizing lines it is difficult to meet the market demands. The results of thisproject are expected to help galvanized strip producers like AM Dofasco to determine, and control theoptimum coating properties that will allow them obtaining the highest productivity and simultaneously achievehigh quality strips with desired product quality. Proper understanding of the jet wiping process and itsinfluence on galvanized product quality has profound impacts on the commercial aspects of hot dipgalvanizing. Based on the current interests in this process optimization, and enhanced productivity (expressedby AM Dofasco hot dip galvanizing lines), an economic impact of $6 million /year is expected from the resultsof this research, which translates to $30 million within five years after completion of this project

在热浸镀锌的情况下，连续移动的钢带被涂上一层薄薄的锌层，以抵抗氧化。通过将基材浸入涂层浴中，保护性金属以其液态施加。然而，在普通的带材速度下，被移动的带材拖曳的液体层对于所考虑的应用来说太厚且不均匀。因此，最终涂层厚度由气刀控制，气刀将二维高速气体射流冲击在液体层上。气刀射流在液体中施加的力导致形成向下流到浴中的回流，从而在基材上留下更均匀和恒定的涂层厚度。然而，操作限制和工艺参数变化仍然会导致显著的涂层不均匀性和过量的锌消耗。本研究计划将侧重于开发一个实验室规模的镀锌试点，其中低熔点液态金属将被用作锌的模拟物，旋转带布置将与气刀相结合，以更详细地可视化喷射擦拭过程。在申请人的实验室开发的最先进的成像技术将用于可视化擦拭过程，涂层波纹和解决方案策略将被提出，用于在工艺参数和气刀设计方面优化擦拭系统。热镀锌生产线存在着诸多问题，难以满足市场需求.该项目的结果预计将帮助镀锌带钢生产商，如AM Dofasco，以确定和控制最佳的涂层性能，使他们能够获得最高的生产率，同时以所需的产品质量生产高质量的带钢。正确理解喷射擦拭工艺及其对镀锌产品质量的影响对热浸镀锌的商业方面有着深远的影响。基于目前对该工艺优化和提高生产率的兴趣（由AM Dofasco热浸镀锌线表示），本研究的结果预计每年可产生600万美元的经济影响，在本项目完成后的五年内可转化为3000万美元