Evolution mechanism of thermal profile of CVC work roll and its effect on plate shape
CVC technology is an advanced flatness control technique that emerged in the 1980s.This technique achieves the desired strip shape control by laterally shifting the working rolls'axes in the rolling mill.The lateral movement helps in obtaining the required convexity of the roll gap,thereby controlling the shape of the outgoing steel strip.During the hot rolling process,changes in the thermal roll profile of CVC working rolls significantly impact the convexity of the roll gap.Accurately predicting the thermal roll profile of the working rolls is crucial for enhancing the precision of strip shape control and reducing roll wear.Taking the 1 780 mm hot continuous rolling production line of a factory as the research object,large-scale finite element analysis software ANSYS/LS-DYNA is used to establish the three-dimensional thermal crown finite element simulation model and the three-dimensional finite element rolling simulation model of the work roll at the fourth stand.The influence of different rolling param-eters such as rolling time,rolling speed,and rolling gap time on the thermal crown of the work roll is analyzed.The thermal crown obtained under different rolling parameters is substituted into the rolling simulation model to analyze the influence of different rolling parameters on the strip shape.At the early stage of rolling,the thermal crown of the work roll changes significantly,and the thermal crown of the work roll increases,while the crown of the strip decreases.After 4 000 s,the thermal crown of the work roll reaches a stable state,and the crown of the strip no lon-ger changes.The rolling speed has a smaller impact on the thermal crown,and its impact on the strip shape is also smaller after the thermal crown becomes stable.As the rolling intermittent time increases,the cooling time increases and the thermal expansion decreases,leading to an increase in the crown of the strip.With the increase in strip width,the heat absorption at the edges of the work roll increases,and the thermal crown at the edges of the work roll changes significantly,leading to an increase in the crown of the strip.The simulation results show that rolling time,rolling interval time,and strip width have a greater impact on strip shape,while rolling speed has a smaller impact.The research results can provide references for on-site roll original crown curve design and strip shape control.
thermal profileCVC work rollflatnessfinite element analysistemperature field
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