热轧金属横向流动规律及其对板形的影响

Transverse flow law of metals and its effect on the shape of a steel strip

采用有限元软件ABAQUS建立热轧金属弹塑性变形模型研究金属横向流动,为了降低模型计算成本,在模型中引入平稳轧制过程中轧件几何模型端面纵向位移沿横向均布的假设.利用此模型仿真研究轧制过程中多个因素对于金属横向流动的影响规律以及相应金属横向流动对轧件板形造成的影响.研究结果表明,接触界面摩擦状态的改变对金属横向流动的影响可以忽略;宽带钢热连轧生产中,在比例凸度不变的情况下,宽度的变化和平均前、后张应力介于实际生产范围内的波动不会引起金属横向流动的变化以及进一步的轧件板形变化;金属横向流动随压下率变化,且使得压下率增加时轧件对称板形向中浪趋势发展;金属横向流动随对称及非对称板廓相似度变化,且金属横向流动的变化显著削弱板廓相似度的改变对轧件板形的影响.为了满足生产现场的在线控制,根据多组有限元模型计算结果建立快速金属横向流动非线性回归模型,为轧件板形的准确调控奠定基础.

The transverse flow law of metals is very important for calculating the shape of steel strips during hot rolling. A metal elastic-plastic deformation model was developed using a general finite element software,ABAQUS. The calculation cost can be significantly reduced by imposing the transverse uniformity of the longitudinal displacement of the strip at the end face during steady rolling.The effect of factors on the transverse flow of metals and the effect of the transverse flow of metals on the shape of steel strips were analyzed using the developed model. Simulation results show that the effect of the friction condition of the contact interface on transverse flow is negligible. Moreover,during hot tandem rolling of wide steel strips,under the condition of constant unit crown,the variation of the width of the steel strip and fluctuation range of the mean front and back tension stresses do not affect the transverse flow and shape of metals. Further,the transverse flow of metals varies with the reduction ratio,which results in a trend toward the middle wave of the strip shape with the increase in the reduction ratio. It also varies with the similarity of the symmetric and asymmetric profiles and significantly reduces the effect of the change of profile similarity on the shape of the steel strip. A metal transverse flow prediction model is developed via the multivariate nonlinear regression method for online control,which lays the necessary foundation for strip shape regulation during hot rolling.