Morphology and structure characterization of hollow granule mold powder for continuous casting

Characteristic parameters of granule morphology (granule diameter and sphericity) and structure (pore size, cross-sectional structure, and porosity) of mold powders were qualitatively and quantitatively analyzed. The results indicated that the granules had a rough surface, good sphericity, and a hollow structure; the internal pores had different diameters, location distributions, and irregular shapes; and the raw material powder particles were interwoven to form a cross-linked network. Energy-dispersive X-ray spectroscopy of the surface and cross-section of the mold powder granules revealed the internal structure and elemental distribution pattern, migration mechanism of the binder, and formation mechanism of the solid crust. The sphericity s values of the mold powder granules were mostly of class B (0.90–0.75 mm), accounting for 72.39%. The s values of more than 90% of granules exceeded 0.8. The porosity values, such as H and ε , increased as the internal pore diameter increased, reaching 0.92 and 0.96, respectively. The H and ε values of more than 90% of the granules were mainly concentrated in the 0.4–0.8 range, and the relationship between H and ε values as well as the variation in granule diameter and pore diameter were mainly consistent.