Formation mechanism and clustering of TiN-Al2O3 inclusions precipitated during solidification of austenitic stainless steel is analyzed in this paper. Steel sample are taken from a continuously cast bloom. Clustering of inclusions was examined with a hypothesis that inclusions gather inside the pores. Precipitation of the inclusions occurs through segregation in the residual melt in the interdendritic area. Size and mean distance of the inclusion particles are calculated with mass balance. Impact fracture test in cryogenic temperature reveals clusters of inclusions inside pores on the fracture surface. Size and distribution of the inclusions are examined using light optical microscopy and scanning electron microscopy. Inclusion's composition is investigated with energy dispersive X-ray spectroscopy analysis. Differential thermal analysis and differential scanning calorimetry Tests determined the transformation temperatures. Results of the experiments are in good agreement with theoretical analysis.

There is a relationship between pores and inclusions. Inclusions and pores are both formed during solidification inside the interdendritic melt. As hypothesis goes, porosity moves to absorb inclusions and form clusters. Focus of this paper is how solidified dendritic structure affects pore precipitation in austenitic stainless steel. Steel sample is a continuously cast bloom. Temperature profile and width of the mushy zone of the strand is modeled according to a constant temperature at the strands surface. Thermal analysis has been performed with differential thermal analysis (DTA) and differential scanning calorimeter (DSC). Primary dendrite arm spacing (PDAS) is measured with light optical microscopy (LOM) and scanning electron microscopy (SEM). PDAS is represented as the weight average of the distance between parallel sets of primary dendrite stems. Pressure field is calculated based on Darcy's law. Pore formation is described through segregation of the gas components and pressure field in the liquid.

The possibility of cluster formation during solidication of steel is explored to explain structures that are seen on the fracture surface of the steel. A hypothesis is built that postulates porosities provide favourable locations for inclusions to agglomerate and form clusters.  A thermodynamic model is constructed to describe precipitation of porosity and inclusions. Formation of inclusions follow a nucleation and growth mechanism. Porosities on the other hand are the product of pressure balance in the liquid.  Motion of pores and inclusions is analysed based on the drag force and  surface  stresses. Gradient of surface tension is also identied as a driving force which acts on the pore surface and would cause motion. It is shown that relative motion of pores and inclusions coupled with  the inclusion tendency to get attached on pore surface makes or a viable mechanism explaining agglomeration of inclusion particles to clusters

Recent work highlighting an anomaly in the modelling of rotary electromagnetic stirring (EMS) in the continuous casting of round steel billets is extended to the case of longitudinal stirring for rectangular blooms. An earlier, still often-cited, model forms the basis of the current analysis, which uses asymptotic methods on the three-dimensional (3D) Maxwell equations and demonstrates how the earlier result for the components of the Lorentz force is but a particular case of a more general form. Time-dependent 3D computations using finite-element methods are also performed to verify the validity of the asymptotic analysis, and the relevance of the results to modulated EMS is noted.