The Effect of Bulk Nucleation Parameters on the Solidification Structure of Large Slabs During Electroslag Remelting and Optimization of Production Process Parameters

In this paper, the moving heat transfer boundary method is adopted to establish a three-dimensional solidification microstructure model based on the coupling technology of the cellular automata method (CA) and finite element method (FE), simulate the ingot growth process, and optimize the nucleation parameters. In addition, this study also explored the influence of process parameters such as melting rate, molten pool temperature, and cooling intensity on the solidification structure of ingots, providing a theoretical basis for process optimization. The results show that the maximum nucleation undercooling degree and the maximum nucleation density have significant effects on different crystal regions of the ingot solidification structure, while the maximum nucleation variance has no obvious effect on the changes in the solidification structure. When the maximum bulk nucleus undercooling degree ΔTv,max = 4 K, the bulk nucleus standard deviation ΔTv,σ = 5 K, and the maximum bulk nucleus density nv,max = 3 × 107, the simulation results of the solidification structure can be well consistent with the experimental results. With the increase in smelting speed, the number of grains in the ingot structure gradually increases, while the average area of grains gradually decreases. The melting temperature and the intensity of side wall cooling have no obvious influence on the solidification structure of the ingot.