中文摘要：

为实现21-6-9高强不锈钢管数控弯曲精确成形,提高其成形质量与成形极限,需要对弯曲过程中壁厚减薄进行有效控制。基于ABAQUS/Explicit有限元软件平台,建立了21-6-9高强不锈钢管数控弯曲三维弹塑性有限元模型,并对其可靠性进行了验证。通过有限元模拟和正交试验,研究了工艺参数对21-6-9高强不锈钢管数控弯曲壁厚减薄影响的显著性及规律。结果表明,影响壁厚减薄的显著性工艺参数依次为芯棒伸出量、管材与芯棒间隙、管材与防皱块摩擦因数、管材与芯棒摩擦因数、管材与压块摩擦因数和弯曲速度,其影响规律为：壁厚减薄率随着芯棒伸出量、管材与防皱块摩擦因数、管材与芯棒摩擦因数、管材与压块摩擦因数、弯曲速度的增大或管材与芯棒间隙的减小而增大。采用多元线性回归方法建立了最大壁厚减薄率与显著性工艺参数之间的回归预测模型,经对比验证,回归预测模型结果与正交试验结果之间的相对误差不超过5%。

英文摘要：

To realize the precise NC bending and improve the forming quality and forming limit of 21-6-9 HSSST,which needed to control wall thinning effectively.A 3D elastic-plastic finite element model of NC bending process of the 21-6-9 HSSST was established based on the platform of ABAQUS/Explicit,and its reliability was validated.The influence significances and laws of process parameters on wall thinning of the 21-6-9 HSSST NC bending were studied by finite element simulation and orthogonal tests.The results show that the significant factors from high to low are the mandrel protrusion length,the clearance between tube and mandrel,the friction between tube and wiper die,the friction between tube and mandrel,the friction between tube and pressure die and the bending speed.Wall thinning becomes large with increasing of the mandrel protrusion length,the friction be-tween tube and wiper die,the friction between tube and mandrel,the friction between tube and pres-sure die and the bending speed.While the wall thinning decreases with increasing of the clearance between tube and mandrel.Moreover,the prediction model between the maximum wall thinning degree and significant process parameters were established by multi-linear regression method.Compared with orthogonal test results,the relative error is less than 5%.