Zr-4合金管材皮尔格轧制过程数值模拟分析：宏观模型的建立、验证及塑性变形分析

皮尔格轧制变形对于锆合金管材的性能有着重要影响,受到学者们的高度重视。长期以来,由于皮尔格轧制是一个高度非线性的三维变形过程,开展实验研究不但成本高昂而且周期较长。本研究以ABAQUS/standard平台,根据多行程皮尔格轧制的运动特点,建立了Zr-4合金管材皮尔格轧制有限元模型,并开展一整个道次的轧制过程模拟。模拟结果表明:预测的管材几何尺寸与实验结果吻合良好,而模拟的轧制力与经典的舍瓦金公式计算结果也比较相符,验证了所建立模型的准确性,可用于进一步仿真分析。模拟结果还表明开口处的管坯应力状态与轧槽底部管坯的应力状态有显著的差别。此外,轧制过程中还存在有明显的剪切变形,而且还有较大幅度的周期性波动,这主要与孔型开口以及管坯回转送进有关。

On the Pilger Rolling of Zr-4 Alloy: Finite Element Modeling and Plastic Deformation Behaviors

Pilger rolling process has a specific influence on the mechanical properties and texture of zirconium alloy cladding tube. Due to its complexity, experimental research on the Pilger rolling process would be very costly. Therefore, a 3D finite element model was built to simulate Pilger rolling with ABAQUS/standard package. Simulation of a full pass of Pilger rolling of Zr-4 alloy tube, including a series of forward strokes and backward strokes, was carried out. The predicted tube sizes agree well with the experimental results. Additionally, the simulated rolling force also matches well with the force calculated by classic empirical formula, which validates the accuracy of the proposed model. The simulation results show that the stress and strain states in groove-side are different from that in groove-bottom. Moreover, large shear deformation happen in the rolled tube. The simulated shear strain displays substantial fluctuations during rolling, which are attributed to the cyclic position change of element (material point) with respect to the groove-side.