高均质大钢锭喂钢带与吹氩协同控制新工艺应用基础研究

Considering the macrosegregation, shrinkage and porosity during the large steel ingot production, a new coordinated control process with steel band feeding and argon blowing for high homogenization large steel ingots will be investigated. Some important theoretical and key technical issues of this new technology will be studied to lay an important theoretical and applied foundation for the industrialization of it. With the theoretical and hot experimental study in laboratory, the mixing characteristics and powder entrapment mechanism will be revealed in ingot mould with gas blowing and the reasonable argon blowing process was presented. Both the melting kinetics and process models will be founded. Mathematical models will be established to describe the multi-phase flow, flow field and temperature field during the casting and solidification in the new process, and the shrinkage, porosity, dendrite growth and evolution and macrosegregation will aslo be described. The characteristics of flow and temperature fields will be clarified. And the regulation mechanism of shrinkage, porosity and solidification microstructure evolution in large steel ingots will be revealed. The formation mehcanism of macrosegregation will also be presented. By the field application test, the application feasibility of the new coordinated control process with steel band feeding and argon blowing for high homogenization large steel ingots will be presented. So the present study will have important theoretical and practical significance in the stable production of high homogenization large steel ingots and it will improve the internal quality of the casting process with bottom pouring. And it will also provide some theoretical guidance and reference for the high homogenization investigation during the casting production of other metals.

针对困扰大钢锭生产的宏观偏析、疏松及缩孔缺陷难题，进行高均质大钢锭喂钢带与吹氩协同控制新工艺研究，对涉及此新工艺的若干重要理论与关键技术问题开展深入研究，为该新工艺技术的工业化奠定重要的理论和应用基础。通过实验室的理论与热态实验研究，揭示钢锭模底吹氩下的钢液混匀特性及渣金卷混机理，并提出合理的吹氩工艺；建立新工艺下喂钢带熔化动力学及熔化过程模型；建立该工艺浇注、凝固过程的多相流、流场、温度场及疏松缩孔、枝晶生长与演变、宏观偏析行为的理论模型，阐明浇注过程流场及温度场行为特征，揭示大钢锭凝固过程疏松缩孔调控机制、凝固组织演变机制及宏观偏析形成机理；在此基础上，开展企业现场应用试验，提出高均质大钢锭喂钢带与吹氩协同控制新工艺应用可行性。本项目研究对高均质大钢锭的稳定生产具有重要的理论和现实指导意义，能改善下注法铸锭的内部质量，并为其它金属铸锭工艺的高均质化技术研究提供借鉴。

基于困扰大钢锭生产的宏观偏析、疏松及缩孔缺陷难题，开展了高均质大钢锭喂钢带与吹氩协同控制新工艺研究。利用物理和数学模拟方法探究了钢锭模底吹混匀特性及渣金卷混行为，通过研究发现，钢锭充型过程和充型结束后最佳的混匀气量分别为60 NL/min和120 NL/min，1/2R为最佳的混匀底吹位置；控制渣金卷混的合理钢锭浇注流量为0.8 m3/h；并提出了合理的吹氩工艺；建立了新工艺下喂钢带熔化动力学及熔化过程模型；建立了该新工艺过程的多相流、流场、温度场数学模型，并揭示了浇注过程流场及温度场行为规律；揭示了大钢锭凝固过程疏松缩孔调控机制及宏观偏析行为，通过研究发现，合理的喂钢带方案能有效改善疏松和缩孔缺陷，且能明显改善铸锭中心区域溶质元素的宏观偏析。通过热态实验，提出了高均质大钢锭喂钢带与吹氩协同控制新工艺的可行性。本项目研究对高均质大钢锭的稳定生产具有重要的理论和现实指导意义，能改善下注法铸锭的内部质量，实现高均质大钢锭的高效、经济生产，本研究还会对其它金属铸锭工艺（铝、铜、锌）的高均质化生产技术研究具有借鉴和理论指导意义。