CHARACTERISTICS OF AGGLOMERATION OF VARIOUS INCLUSION PARTICLES ON MOLTEN STEEL SURFACE

The behavior of various inclusion particles at inert gas/molten steel interface was ''in-situ'' studied with a confocal scanning laser micro scope. Solid CaO-Al2O3 and solid CaO-Al2O3-SiO2 inclusion particles we re subjected to quick agglomeration to form clusters which densified a nd deformed later. Capillary attraction was found responsible for the agglomeration and densification. The capillary effect also operated be tween solid CaO-Al2O3 inclusion particle and liquid CaO-Al2O3 inclusio n particle pairs, making the densification and deformation of the soli d inclusion particles much easier. The attraction force was found to b e in the range of 10-(16)-10(-13) N for different particles and extend ed to a distance of up to 100 mu m. However, such capillary attraction was not at all found between liquid CaO-Al2O3-SiO2 inclusion particle s. Even when the two liquid particles came in touch, merger took place only after contacting for-a while. The merger of liquid CaO-Al2O3 par ticles was even more difficult for small particles of less than 7 mu m , but easier for particles larger than 24 mu m. These phenomena are di scussed in terms of inert gas/oxide inclusions/liquid steel three-phas e interfacial interaction.