Wang Yong, Song Jingxin, Cheng Nailiang, Guo Zhenhe, Li Jingshe, Yang Shufeng, Zhao Mengjing, Wang Cun
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100080, China.
Baoteel Shanghai Meishan Iron and Steel Ltd., Nanjing 210039, China.
Materials (Basel). 2022 Apr 1;15(7):2590. doi: 10.3390/ma15072590.
In this study, the industrial, experimental effect of a plasma heating system in the form of graphite electrode in the tundish of double-strand slab caster was evaluated for the first time. The system uses three graphite electrodes, two of which are cathodes and one of which is an anode, to form a conductive loop through molten steel in the tundish. The system is built on an old two-strand slab caster and is installed on the premise that the original ladle tundish equipment remains unchanged. The normal working power of the system is up to 1500 kW, and the heating rate of molten steel in the tundish can reach 1.0 °C/min under conditions of 5 t/min total steel throughput and a tundish capacity of 50 t. After the system was put into operation, the purity of molten steel undergoing heating was investigated. The sample analysis of low carbon steel and ultra-low carbon steel before and after heating showed that the contents of N and O in the steel did not increase, while the size of the oxide inclusions near the heating point increased but showed little change in terms of the overall quantity. This process benefited from the addition of inert gas during the heating process to control the atmosphere in the heating area, which prevents reoxidation. The sample analysis also showed that there is no obvious carbon absorption phenomenon after heating, and the fluctuation in C content is within 0.0001%, which is consistent with the general production results. By using this system, the temperature of molten steel in the steelmaking process can be reduced by 10~15 °C, allowing continuous low superheat casting to be supported, which is helpful for reducing production costs and improving the solidified structure inside the slab. The results of the study show that the plasma heating technology can be applied to the continuous casting of low carbon-nitrogen steel slabs, which shows the benefits of reducing emissions and improving production efficiency.
在本研究中，首次评估了双流板坯连铸中间包中石墨电极形式的等离子体加热系统的工业实验效果。该系统使用三根石墨电极，其中两根为阴极，一根为阳极，通过中间包内的钢水形成导电回路。该系统基于一台旧的双流板坯连铸机构建，在原钢包中间包设备保持不变的前提下进行安装。该系统的正常工作功率高达1500千瓦，在总钢产量为5吨/分钟且中间包容量为50吨的条件下，中间包内钢水的加热速率可达1.0℃/分钟。该系统投运后，对加热过程中钢水的纯净度进行了研究。低碳钢和超低碳钢加热前后的样品分析表明，钢中N和O的含量没有增加，而加热点附近氧化物夹杂物的尺寸有所增大，但总量变化不大。这一过程得益于加热过程中添加惰性气体来控制加热区域的气氛，从而防止再氧化。样品分析还表明，加热后没有明显的增碳现象，C含量的波动在0.0001%以内，这与一般生产结果一致。通过使用该系统，炼钢过程中钢水的温度可降低10~15℃，从而支持连续低过热度浇铸，这有助于降低生产成本并改善板坯内部的凝固组织。研究结果表明，等离子体加热技术可应用于低碳氮钢坯的连铸，显示出减排和提高生产效率的优势。
