基于高通量试验原理82B连铸坯组织形貌特征

 凝固组织形貌对铸坯宏观偏析的形成有非常重要的影响,并在一定程度上决定了铸坯后续的加工使用性能。基于高通量试验原理,引入分形维数和无量纲周长对82B帘线钢连铸坯凝固组织形貌特征展开分析。结果表明,对于连铸坯两侧中间区,窄宽度长区域取样方法得到的凝固组织面积率可近似等效为固相率;同时凝固组织整体形貌的分形维数随着固相率的增加而增加,但其无量纲周长呈现相反的趋势,故两者对凝固组织渗透率大小存在相反的影响作用;计算表明,实际铸坯组织的渗透率最小值对应的固相率为0.667。提出了一种基于实际铸坯分析凝固组织形貌特征变化规律的新方法,同时能为连铸末端电磁搅拌与轻压下等偏析控制技术的最佳作用固相率提供参考。

Morphology characteristics of macrostructure in 82B steel billet based on high throughput experimental principle

The morphology of the solidification structure has a very important influence on the formation of macrosegregation in billet and determines its subsequent processing performance to some extent. This paper introduces the fractal dimension and dimensionless perimeter to analyze the morphology characteristics of solidification structure in billet of 82B cord steel based on the principle of high throughput experiment. The results show that for the middle zone on both sides of the continuous casting billet,the area ratio of solidification structure obtained by the narrow-width and long-region sampling method can be approximately equivalent to the solid fraction. Meanwhile,the fractal dimension of the overall morphology of the solidification structure increases with the solid fraction,but its dimensionless perimeter shows the opposite trend,so the two have opposite effects on the permeability of the solidification structure. And the calculation shows that the solid fraction corresponding to the minimum permeability of the solidification structure in the actual billet is 0.667. A new method for analyzing the evolution law of solidification structure based on actual casting billet is proposed,which can also provide a reference for the best action area of segregation control technology such as final electromagnetic stirring and soft reduction in continuous casting.