TA18高强钛管数控弯曲回弹工艺参数影响的显著性分析

Significance Analysis of Processing Parameters Effect on Springback in High Strength TA18 Tube NC Bending

高强钛管数控弯曲卸载后会产生显著回弹现象,这严重影响着管件的几何和形状精度。基于ABAQUS平台建立了TA18高强钛管数控弯曲、抽芯及回弹三维弹塑性有限元模型,并进行可靠性评估。通过虚拟正交试验,研究工艺参数对TA18高强钛管数控弯曲回弹的影响显著性及规律。结果表明,影响回弹的显著工艺参数依次为:芯棒伸出量、弯曲模-管子摩擦系数、压块-管子间隙、压块相对助推速度和芯棒-管子间隙;其影响规律为回弹角随芯棒伸出量的增大而减小,随弯曲模-管子摩擦系数、压块-管子间隙和芯棒-管子间隙的增大而增大,当压块相对助推速度小于1时,回弹角明显增大。并采用多元逐步线性回归方法建立了回弹角与显著工艺参数之间的预测模型,经对比验证,对于规格为φ12mm×t1mm×R36mm的TA18高强钛管,此模型预测结果与虚拟试验结果之间误差不超过5%。

The significant springback occurring after unloading in numerically controlled （NC） bending of high strength （HS） titanium alloy tube will affect the geometric and shape accuracy severely. A 3D elastic-plastic FEM containing NC bending, mandrel retracting and springback process of HS TA18 tube was established based on ABAQUS platform, and reliability assessment has been carried out. The influence significance and rules of processing parameters on springback of HS TAt8 tube have been investigated by means of virtual orthogonal tests. It is shown that mandrel protrusion length, friction coefficient between bending die and tube, clearance between pressure die and tube, relative boosting velocity and clearance between mandrel and tube have a significant influence on springback. The mandrel protrusion length has the negative effect on the springback angle. The friction coefficient between bending die and tube, clearance between pressure die and tube, as well as clearance between mandrel and tube have the positive effects. The springback angle increases obviously when relative boosting velocity is lower than 1. Moreover, the prediction model between springback angle and significant processing parameters was established by multi-linear stepwise regression. Compared with virtual tests results, the relative error is less than 5% for φ12 mm×t1 mm×R36 mm HSTA18 tube.