(西北工业大学 凝固技术国家重点实验室 材料学院，西安 710072)
摘 要: 为了控制矩形管绕弯成形的回弹和截面变形，建立考虑压块力、速度加载条件的回弹和截面变形有限元预测模型，并对其可靠性进行实验验证。基于所建模型研究压块的摩擦因数、夹持压力和助推速度对H96矩形管回弹与截面变形的影响规律。结果表明：摩擦因数和夹持压力越大，回弹角和横截面高度变形越小。但压块对横、纵截面畸变的作用完全相反；芯头支撑区域内助推速度的变化能够影响回弹量，且不会加剧截面变形。提出变助推速度的压块边界条件组合方案，实现了弯曲角度小于90°和大于等于90°弯管的回弹量分别降低55.31%和36.45%，60°弯管的高度变形量平均降低1.79%，90°和120°弯管的高度变形量最大分别降低5.98%和6.35%。
关键字: 绕弯成形；H96矩形管；回弹；截面变形；工艺参数；有限元模拟
（State Key Laboratory of Solidification Processing, School of Materials Science and Engineering,
Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:In order to control springback and section deformation of rotary-draw bending of rectangular tube, the finite element model for springback and sectional deformation prediction, which considers the loading and velocity conditions of pressure die, was established and verified by experiment. Based on the model, the impact of friction coefficient, pressure and boosting velocity of pressure die on springback and section deformation of H96 rectangular tube was investigated. The results show that the larger the friction coefficient and the clamping pressure are, the smaller the springback angle and the cross-section height deformation are. However, the impacts of pressure die on deformations of cross-section and longitudinal-section are completely opposite. The change of boosting velocity within core-filled area can influence the springback amount, while not exacerbate section deformation at the same time. Then, the combinations of pressure die boundary conditions of variable boosting speed were proposed. And by which, it is realized that springback angles are decreased by 55.31% and 36.45%, respectively, for bent tubes smaller than 90° or no less than 90°. The cross-section height deformations are reduced by 1.79% for 60° tube on average, and 5.98% and 6.35%, respectively, for 90° tube and 120° tube at most.
Key words: rotary-draw bending; rectangular H96 tube; springback; section deformation; process parameters; finite element simulation
