热轧带钢板凸度纵向分布三重调控研究与应用

Research and application on threefold regulation of crown distribution in rolling direction of hot-rolled strip

由于带钢头尾存在温差,并且薄规格带钢轧制时间较长,承德钒钛1780 mm热轧生产线薄规格带钢板凸度产生明显纵向衰减现象,影响带钢质量。针对这一现象,对现场包括CVC原始辊型、工作辊横移量设置以及各机架弯辊力设置进行了分析,发现在不改变现有冷却设备、轧制节奏的前提下,现有工艺参数已达到板凸度控制极限。基于此分析,提出了CVC原始辊型优化+工作辊横移控制+弯辊力动态调整的三重组合调控方法,为改善现场带钢板凸度衰减提供了理论指导和依据。基于金属三维变形模型和辊系弹性变形模型,考虑现场工况和工艺特点,构建了适用于该钢厂热轧薄规格带钢的板凸度控制模型。提出了分别以F1、F1和F2、F1~F3和F1~F4为目标的4种辊型优化方案,并将4种辊型优化方案结合工作辊横移、弯辊力动态调整后对板凸度纵向分布的影响及其分布规律进行了分析研究。结果表明,以(45±15)μm为目标板凸度时,4种优化方案可使带钢分别获得34~45、37~45、40~47、41.2~49.4μm的板凸度纵向分布,对应的凸度衰减量分别为11、8、7、8.2μm,同时可将F1、F2、F3、F4机架弯辊力调控窗口分别提高500、550、740、680 kN。除此之外,将该方法应用于板凸度衰减最为明显的1.5 mm×1250 mm规格带钢现场生产,板凸度衰减量可减小至8~10μm。

Due to the temperature difference between the two ends of the strips and the longer rolling time of the thin strips,a significant attenuation of thin strips in rolling direction occurred on the 1780 mm hot-rolling production line of Chengde Vanadium and Titanium New Material Co.,Ltd.,affecting the quality of strips.In response to this phenomenon,an analysis was conducted on the site,including the original roller shape of CVC,the lateral displacement setting of work rolls,and the bending force setting of each stand.It was found that the existing process parameters had reached the limit of plate crown control without changing the existing cooling equipment and rolling rhythm.Based on that,the threefold regulation combining original roller shape optimization of CVC,axial shifting control of work roll and dynamic adjustment of bending force is put forward,which provides theoretical guidance and basis for improving the crown attenuation of strips.Based on the three-dimensional metal deformation model and the elastic deformation model of the roll system,a crown control model suitable for the hot-rolled thin strips was constructed in light of the on-site working conditions and process characteristics.Four roller shape optimization schemes were proposed with the goals of F1,F1-F2,F1-F3,and F1-F4,respectively,which then were combined with the lateral displacement of work rolls and the dynamic adjustment of bending force.The effects on longitudinal distribution of crown and the rules of it were analyzed.The results show that with a target crown of(45±15)μm,the crown distribution of strip steel in rolling direction can be 34-45,37-45,40-47 and 41.2-49.4μm respectively using the optimization schemes above.The corresponding attenuations are 11,8,7,and 8.2μm respectively.The bending forces of F1 to F4 are increased by 500,550,740,and 680 kN respectively.In addition,the crown attenuation can be reduced from 8μm to 10μm after this method is applied to the production line of 1.5 mm×1250 mm strips.