棒材三辊孔型自由宽展流动模型

Flow model of free spread in three-roll passes of rod

棒材三辊成形具有在短时间内实现控温连轧、在交变应力作用下发生累积大变形的特征,尤其适合于变形温度区间窄、变形抗力高的金属连续成形。金属塑性形变规律的研究对于连续轧制稳定性、产品精确成形和优异综合性能具有重要影响。通过数值模拟研究TC4钛合金棒材在三辊连轧过程中金属塑性应变和辊缝区域金属流动的规律,结合孔型宽展计算公式,进一步完善构建不同孔型系统辊缝区域金属质点的自由宽展流动模型,从而能够精确表征变形体的几何轮廓和出口横断面积。并在三辊轧机上进行TC4钛合金棒材连轧试验,获取的试验样品尺寸精度检测结果与模拟结果吻合较好。因此,建立的自由宽展流动模型有效地提高了棒材连轧成形的稳定性和成材率,为高性能材料制备提供理论依据。

The three-roll forming of rod has the characteristics of achieving temperature-controlled continuous rolling in a short time and accumulating large deformation under the action of alternative stress, and it is especially suitable for continuous forming of metal with narrow deformation temperature range and high deformation resistance. Therefore, the study on the law of metal plastic deformation has an important influence on the stability of continuous rolling, accurate forming of product and excellent comprehensive performance. Then, during the three-roll continuous rolling process, the plastic strain and the flow law in the roll gap area of TC4 titanium alloy rod were studied by the numerical simulation method, and combined with the calculation formula of pass spread, the free spread flow model of metal particles in the roll gap area of different pass systems was further reconstructed, which could accurately characterize the geometric contours of deformable body and the cross-sectional area of outlet. Furthermore, the continuous rolling tests of TC4 titanium alloy rod were carried out on the three-roll mill, and the dimensional accuracy of sample from the experimental results was in good agreement with the simulation results. Thus, the established free spread flow model could effectively improve the forming stability and yield of rod continuous rolling to provide the theoretical basis for the preparation of high-performance materials.