Modelling of ingot size effects on macrosegregation in steel castings
Modelling of ingot size effects on macrosegregation in steel castings
复制标题
钢锭尺寸对铸钢件宏观偏析影响的建模
DOI：
10.1016/j.jmatprotec.2017.09.004
复制
发表时间：
2018-02-01
影响因子：
6.3
通讯作者：
Li, Jianguo
中科院分区：
文献类型：
--
作者：
Ge, Honghao;Ren, Fengli;Li, Jianguo
采用混合柱状枝晶-等轴晶三相凝固模型，考虑了二次枝晶间距(SDAS)、等轴晶的形核和长大、等轴晶的沉积、柱状枝晶的生长和柱状晶向等轴晶的转变(CET)，研究了不同尺寸钢锭宏观偏析的形成过程。用一个已报道的实验案例(55,000公斤钢锭)验证了当前三相模型的合理性。预测的偏析形态与实验结果吻合较好。利用该凝固模型研究了不同尺寸钢锭(50 kg、400 kg、3300 kg、6000 kg、25000 kg、55000 kg和97000 kg)宏观偏析的形成过程。结果表明，随着钢锭重量的增加，宏观偏析的严重程度增加。枝晶等轴晶的热-溶浮力和沉降性在决定不同铸锭最终的偏析形态中起主导作用。当铸锭重量超过25000 kg时，最大负偏析增大，这是由于枝晶等轴晶的有限堆积造成的。
A mixed columnar dendritic-equiaxed three-phase solidification model that considers the secondary dendrite arm spacing (SDAS), nucleation and growth of equiaxed crystals, sedimentation of equiaxed crystals, growth of columnar dendritic trunks, and columnar-to-equiaxed transition (CET) was employed to study the formation of macrosegregation in steel ingots of different sizes. A reported experimental case (55,000 kg ingot) was used to verify the rationality of the current three-phase model. The predicted segregation patterns were in good agreement with the experimental results. The formation of macrosegregation in a series of steel ingots with different sizes (50 kg, 400 kg, 3300 kg, 6000 kg, 25,000 kg, 55,000 kg, and 97,000 kg) was studied using this solidification model. The results showed that the severity of macrosegregation increased with the increasing ingot weight. The thermal-solutal buoyancy and sedimentation of the dendritic equiaxed grains played dominated roles in determining the final segregation patterns in the different ingots. Additionally, the maximum negative segregation increased until the ingot weight exceeded 25,000 kg, which was caused by limited packing of the dendritic equiaxed grains.