Abstract: The submerged entry nozzle is one of the key factors determining the molten steel flow field in the mold and plays an irreplaceable role in suppressing excessive meniscus fluctuations, preventing poor melting of the meniscus protective slag and regulating the molten steel flow field in the mold. Using high-temperature quantitative velocity measurement method and numerical simulation methods, the effects of 38 mm and  48 mm inner diameter convex-bottom SEN, and 48 mm inner diameter wavy-bottom SEN on the flow field, argon bubble distribution, meniscus fluctuations, solidification, and inclusion capture in the 840 mm×180 mm continuous casting mold under different casting speeds were studied. High-temperature velocimetry measurements of mold surface velocity were conducted for 38 mm inner diameter convex-bottom SEN at casting speeds of 0.8, 1.0, and 1.2 m/min. The good agreements between measurement and numerical simulation results validated the reliability of the mathematical model. The simulation results showed that when the casting speed was 1.2 m/min, the mold with 48 mm inner diameter wavy-bottom SEN showed smaller surface velocity, more uniform bubble distribution, reasonable overall meniscus fluctuations, uniform solidifying shell growth, and fewer captured inclusions (≤150 μm), demonstrating the best overall performance.

Key words: continuous casting mold, submerged entry nozzle, flow field, casting speed, inclusions