70号钢连铸过程的凝固传热模型与组织研究

Research on continuous casting solidification heat transfer model and structure of No.70 steel

连铸过程的冷却制度直接影响连铸坯质量和凝固组织,因此本文建立了二维凝固传热数学模型,对连铸过程进行了模拟,得到铸坯的温度场分布及坯壳厚度的变化。首先,通过模拟结果与实际生产的连铸坯组织结合,研究了铸坯组织疏松问题。然后,模拟过程中采用控制变量法,通过改变连铸工艺参数,进一步研究了过热度、结晶器水量、拉速及比水量等对铸坯温度及坯壳厚度的影响,得出连铸一系列规律,为指导现场二冷水的分配提供了重要依据。

The cooling system of the continuous casting process directly affects the billet quality and the solidified struc- ture. Therefore, the two-dimensional solidification heat transfer mathematical model was established and the continuous casting process was simulated. The change of the temperature field and the thickness of the billet were obtained. Firstly, the slab looseness problem was studied through combining the simulation results with the solidification structure of the continuous casting billets. The results showed that the most serious area of loosening was generated in the residual liquid phase after the slab entered the straightener. After that, in the process of simulation, the influence of the superheat, the amount of water in the mold, the casting speed and the specific water amount on the temperature and thickness of the bil- let was studied by controlling variable of the continuous casting process. A series of laws of continuous casting have been obtained, which provide an important basis for secondary cooling water distribution of actual production.