Study On Mold Oscillation Control Based On Analysis Of Meniscus Interface Behavior

The surface quality defects of continuous casting slab are mostly originated from the mold.Mold oscillation is one of the important means to improve the slab quality.The solidification process of molten steel can be controlled by mold oscillation based on the vibration mechanism.Study effect of mold oscillation on the behavior of meniscus interface has important significance to enhance the quality of continuous casting slab.In this study,a new non-sinusoidal oscillation mode was developed for improving the slab quality based on the study of meniscus interface behavior.The study built a mechanical model based on the theory of material mechanics.In combination to the deformation of initial solidifying shell and mechanical analysis,the formation mechanisms of initial crack and the process of slag consumption were proposed.The main conclusions are obtained as follows:(1)A new non-sinusoidal oscillation mode was developed by using segmented functions.New control variable defined as equal-velocity stage factor was introduced to regulate the oscillation.The new oscillation mode reduced the friction and enhanced the slag consumption effectively.(2)This article regarded the initial solidified shell as cantilever beams with variable cross section,and calculated its behavior in mold oscillating period.The deformation quantity reached its maximum under meniscus 20.1 mm during positive strip time.The maximum deformation quantity during positive strip time and during negative strip time reaches to 0.21 mm and 0.17 mm,respectively.(3)The friction on the initial solidified shell is liquid friction during positive strip time and its minimum value is 45.4 Pa.The liquid friction on the part of initial solidified shell transform to solid friction if the deformation quantity is too large during negative strip time.Initial crack is most likely to occur at this stage.The maximum value of solid friction reaches to 3.12 kPa at meniscus 11.8 mm.(4)The liquid slag is infiltrated down from the middle-late stage of positive strip time to the early stage of the next positive strip time,including the entire negative strip time.The distance between mold surface and solidifying shell is a decisive factor in slag consumption during the half of negative strip time.