TA2圆管辊弯成型边波缺陷及机理研究

目的 为消除TA2薄壁圆管在辊弯成型过程中产生的边波缺陷，研究分析不同成型方法中TA2薄壁圆管焊缝处纵向应力及应变大小的变化规律。方法 运用专业型钢软件COPRA RF和有限元MSC.MARC商业软件建立符合生产标准的三维薄壁圆管模型，展开多机架连续辊弯成型过程的有限元仿真，并进行辊弯成型试验验证。结果 试验结果表明，成型方式不合理是引起TA2薄壁圆管辊弯成型边波的重要原因。随着道次间成型结束后塑性应力与纵向应力的累积，TA2薄壁圆管焊缝处出现褶皱现象，即薄壁圆管产生边波缺陷。通过有限元分析及TA2纯钛薄壁圆管生产试验验证发现，基于普通成型法加工的薄壁圆管焊缝处失稳区辊弯纵向应变波动峰值由0.6%降低到基于上山法成型的0.3%。结论 使用上山法可以消除TA2纯钛薄壁圆管在辊弯加工工艺中产生的边波缺陷，提高了产品精度并为后续装配提供了保障，研究结果为消除工业纯钛圆管边波缺陷奠定了良好的理论基础。

Edge Wave Defects and Mechanism of TA2 Round Tube Roll Forming

The work aims to study and analyze the change rule of longitudinal stress and strain at the weld of TA2 thin-walled round tube under different forming methods, in order to eliminate the edge wave defects produced in the roll forming process. Professional section steel software COPRA RF and finite element business software MSC.MARC were used to build three-dimensional thin-walled round tube model in conformity with the production standards. Then, the FEM simulation of multi-frame continuous roll forming process was carried out and the roll forming test was conducted for verification. According to the test results, the unreasonable forming method was an important reason to produce the edge wave in the roll forming process of TA2 thin-walled round tube. With the accumulation of plastic stress and longitudinal stress after inter-pass forming, the wrinkles appeared at the weld of TA2 thin-walled round tube, that was, the edge wave defect of TA2 thin-walled round tube. Through FEM analysis and the verification of TA2 thin-walled round tube test, the peak value of longitudinal strain fluctuation of roll forming at the weld instability zone of thin-walled round tube processed by ordinary forming method decreased from 0.6% to 0.3% obtained based on uphill forming method. The uphill forming method can eliminate the edge wave defects of TA2 thin-walled round tube in roll forming process, which improves product accuracy and guarantees subsequent assembly. At last, the study results lay a good theoretical foundation for eliminating the edge wave defects of pure titanium thin-walled round tube.