Optimization of submerged entry nozzle parameters for ultra-high casting speed continuous casting mold of billet

Controlling the flow behavior in the mold in an appropriate way is the basis for realizing the billet ultra-high speed continuous casting. Based on the new proposed physical water modeling experiment considering the effects of solidified shell and hydrostatic pressure, the flow behavior in the mold with cross section of 160 mm × 160 mm during continuous casting of billet is regulated by optimizing the inner diameters and immersion depths of submerged entry nozzle at the ultra-high casting speeds of 5.0–6.5 m/min. The results show that under the premise of no slag entrainment, as well as uniform coverage and keeping good fluidity of liquid slag layer on the top free surface of the fluid in the mold, the appropriate parameters of submerged entry nozzle under the ultra-high casting speed of billet are 50 mm in inner diameter, 95 mm in outer diameter and 180 mm in immersion depth. And on the basis of the obtained parameters of submerged entry nozzle, it can be known that the reasonable ranges of level fluctuation and impacting depth of the stream in the mold are about 0.82–1.11 and 593–617 mm, respectively.