关键词: 大圆坯, 自旋式浸入水口, 碳偏析, 低倍, 夹杂物,

Abstract: The effect of six-hole swirling flow submerged entry nozzle on quality of LZ50 railway axle steel continuous casting bloom Φ 690 mm including macrostructure, inclusions, carbon segregation etc has been studied. Tthe results show that,compared with the traditional five-hole nozzle, the maximum central shrinkage cavity size in the center of continuous casting bloom with six-hole swirling flow submerged entry nozzle decreases from 22.7 mm to 12. 8 mm, the average shrinkage cavity size decreases from 7. 8 mm to 5. 5 mm,and the shrinkage cavity larger than 15 mm disappears,the rating of porosity is all quality 1 ,and the central equiaxed crystal region increases by 74. 1%. The inclusion floating effect is remarkable ,the number of inclusions is obviously reduced, and inclusions larger than 40μm are eliminated ； the segregation ratio is reduced from 0.92 ~ 1. 1 to 0.93 ~ 1.05.