Abstract
The effect of nonsinusoidal oscillation at different modification ratios (α) on slag lubrication was investigated during mold oscillation. A validated and reliable multiphase model was employed, which involved flow and solidification of the molten steel and mold slag. The main results revealed that a large amount of liquid slag at the entrance of the mold–strand channel reflowed into the slag pool at the middle of the negative strip period. The phenomenon was more distinct, with an increase in the modification ratio. The modification ratio had no obvious effect on the average thickness of the liquid film at different depths below the meniscus. A modification ratio of 0.5 caused less fluctuation of the transient liquid film. Quantitative prediction of slag consumption indicated that as the modification ratio increased from 0.2 to 0.5 to 0.8, the average values were 0.278, 0.286, and 0.279 kg/m2, respectively. Shell solidification and growth near the meniscus mainly occurred when the mold was descending, which not only depended on the heat flux, but also on the liquid slag flow, the pressure driven by slag rim, and the mold oscillation. Optimization of the modification ratio of nonsinusoidal oscillation could be an alternative to delay growth of the initial shell towards the molten steel. A modification ratio of 0.5 had the least robust shell tip at the meniscus, thereby reducing entrapment of inclusions and bubbles by the shell tip.
Highlights
Mold oscillation technology was pioneered by Junghans [1,2] in the early 1930s and successfully applied to the continuous casting of nonferrous metal, which initiated large scale industrial application.In 1949, Junghans and Rossi [1,2] first implemented an oscillating mold for the continuous casting of steel, with the aim of smooth demolding and friction reduction on the strand surface
The flow-back tendency circumstances of liquid slag predicted in the model was consistent with the reported by Jonayat and increased with the increase of α
The phenomenon is caused drive of the copper plate, which imposes an oppressive function on the liquid slag and plays the role by the solid rim descending under the drive of the copper plate, which imposes an oppressive of a piston occupying the space of the liquid flux [22]
Summary
Mold oscillation technology was pioneered by Junghans [1,2] in the early 1930s and successfully applied to the continuous casting of nonferrous metal, which initiated large scale industrial application.In 1949, Junghans and Rossi [1,2] first implemented an oscillating mold for the continuous casting of steel, with the aim of smooth demolding and friction reduction on the strand surface. The copper plates are always periodically moved downward a certain distance at a velocity equal to the casting speed, and rapidly returned to the initial position [1]. Both the absence of gradual varied velocity difference between the mold (V m ) and strand (V c ) and the abrupt change in direction of mold movement could cause negative effects on oscillating devices and increase the incidence of breakout. This technique performed well in healing tiny cracks on the strand surface during the negative strip period (NSP; tn , the portion of the oscillation cycle where the mold descend faster than the shell) [3,4,5] and in the demolding process during the positive strip period
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
