Service life of long stopper(LS) and submerged entry nozzle(SEN) in continuous caster influences the quality and productivity of steel. Life of those refractories is much shorter when they are used in high oxygen steel like free machinable steel than in regular carbon steel. It is because carbon in refractories is lost by attack of free oxygen solved in the molten steel. The refractory grade aluminium nitride(AlN) powder developed for ourselves was added to the conventional Al_2O_3-C refractory material to develop AlN-Al_2O_3-C material. The developed material was applied to the nose of LS and the collar of SEN, which were used in a caster of Bi-resulferized free machinable steel with high oxygen content. The developed material showed less erosion than the conventional MgO-C material so that the life of refractories could be prolonged. Dense oxide layer formed at hot face by reaction of AlN and oxygen in steel melt was confirmed through analysis of the material after use. The layer was believed to play a role of prevention of carbon loss from refractories. Quality and productivity of steel were expected to be better when AlN included refractory would be used.
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