A New Tundish Design to Produce a Swirling Flow in the SEN During Continuous Casting of Steel

Abstract

A new tundish is designed with the aim to produce a swirling flow in a tundish SEN by an economical way of using the steel flow potential as the required power. This design is easily obtained by adding a cylindrical part of the tundish onto a traditional tundish. The results show that a swirling flow in the SEN of the new tundish is successfully obtained, also, that the tangential velocity in the SEN can reach around 1.6 m s À1 . The installation of weirs in the cylindrical tundish can contribute to stabilize the steel flow at the top of the tundish. However, this reduces the swirling flow intensity in the SEN around 30%. In addition, the possibility of slag entrainment at the top of the tundish is analyzed. The calculated Weber Number is around 5.0 for no weir case and 2.8 for the weir case, which means that the risk of slag entrainment is small. A high value of shear stress is found on the SEN wall due to the swirling flow in SEN. A further investigation shows that a smooth transition of SEN inlet can reduce the maximum shear stress level in the SEN, without decreasing the swirling flow intensity.

A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design

“…Two methods to realize a swirling flow or rotational flow during the steel casting have been intensively studied, namely, the swirling flow SEN method [26][27][28][29][30][31][32][33][34] and the mold-electromagnetic stirring (MEMS) method. [35][36][37][38] When using a swirling flow SEN, the penetration depth of the SEN outlet flow in mold was found to decrease.…”

“…[36] Therefore, the use of a swirling flow or a rotational flow during metal castings is becoming an important way to produce high-quality steels. However, previous studies [26][27][28][29][30][31][32][33][34][35][36][37][38] of swirling flows during steel castings mainly focused only on the influence on the steel flow itself. Furthermore, previous studies focusing on the inclusion behavior in steel flows have mostly been carried out for conventional continuous casting processes, where no rotational steel flow phenomena exist in the horizontal cross sections of the SEN or the mold.…”

“…Previous studies on the behaviors of nonmetallic inclusions in swirling steel flows are limited. Yang et al [32,33] investigated the nonmetallic inclusion motion in a swirling flow, which was obtained by applying electromagnetic stirring outside the SEN. Ni et al [34] investigated the behaviors of Al 2 O 3 and Ce 2 O 3 inclusions in a swirling flow SEN obtained from a new tundish design. It was found that large size light nonmetallic inclusions move toward the swirling flow center, due to the centripetal separation effect.…”

“…It was found that large size light nonmetallic inclusions move toward the swirling flow center, due to the centripetal separation effect. [34] Hou et al [39] investigated the inclusion removal in a swirling flow chamber, which was installed at the tundish inlet region. It was found that this design is suitable to use for the removal of 20-lm inclusions but not large size inclusions, compared to a conventional tundish.…”

“…[39] However, these simulation studies were carried out using swirling flow fields, which were solved by using the k-e type turbulence model in combination with a standard wall function. [32][33][34]39] Thereafter, a Lagrangian particle tracking scheme was used to describe the inclusion motion in the solved flow fields. Therefore, the isotropic turbulent fluctuations were assumed and the turbulent boundary layer was not resolved.…”