Formation of multi-type inclusions during the cooling and solidification of steel: A trend model

Abstract

This paper presents a trend model of the competitive formation of multi-type inclusions during the cooling and solidification of steel. The model is able to predict the evolution of various inclusions, including their type, composition and size distribution. In the calculations, the thermodynamic library, ChemApp, was applied to perform a thermodynamic equilibrium calculation. Homogeneous nucleation, diffusion-controlled growth and dissolution were employed to simulate the size distribution evolution. At the same time, the collision of inclusions of the same type were considered in a simplified way. The inclusion stabilities were validated by laboratory experiments, which offered a strong basis for the simulations. Using the proposed model, the influence of alloying temperature and oxygen content on the formation of multi-type inclusions was investigated. The results indicated that decreasing the alloying temperature resulted in a higher number density and finer size of different oxides. The oxygen content affected the formation of various oxides in different ways. The predictions, based on the mechanism of competitive nucleation and growth, are discussed and explained. It is believed that the calculations deepen the understanding of the competitive formation of multi-type inclusions. The predicted trends provide a valuable reference for inclusion control and experiment design.