Morphology, Soundness and Segregation Improvement of Bloom Castings by Using Swirling Flow Nozzle

摘要

The as-cast structure improvement of bloom castings for special steels has been studied based on the adoption of a kind of newly-designed swirling flow nozzle (SFN). As compared with the conventional straight nozzle, the morphology, soundness and centerline segregation of the castings have been improved remarkably. The over-sized shrinkage porosity at the centre area has been eliminated together with the popular radial centre crack, and the index of the centerline segregation has been alleviated accordingly. Based on the coupled thermal and flow dynamic modeling, the positive results obtained are attributed to the remarkable superheat dissipation under the new feeding mode.