Inclusion agglomeration - a key issue contributing to ‘Inclusion Engineering’ in advanced steels

Abstract

Better understanding of the agglomeration behavior of non-metallic inclusions in the steelmaking process is of vital importance to control the cleanliness of the steel product. Less inclusions in the steel ingot are always desired by the steelmakers to reduce the risk of engineering problem, e.g. nozzle clogging and improve the final product’s mechanical properties. On the other hand, non-agglomerated inclusions with fine size can be utilized in different processes to optimize the microstructure and improve the final property. Both aspects correspond to the concept of ‘Inclusion Engineering’. In this work, the inclusion motion and agglomeration behaviors at the interfaces between steel/gas and steel/slag are overviewed, and former results in the open literature including the in-situ characterization as well as theoretical development are summarized. The authors’ work is also mentioned. Furthermore, previous results of the behaviors of the inclusion agglomeration at the bulk of the steels are also mentioned in comparison to the agglomeration behaviors of inclusions at the interfaces. Mechanisms of the attraction force between inclusions at these two cases are critically discussed. This work aims to provide an overview of the agglomeration behaviors of inclusions at different stages and provide a way forward to the future research of this important phenomenon contributing to ‘Inclusion Engineering’ in steels.