芯模参数对高强度薄壁管数控弯曲成形质量的影响

Influence of mandrel parameters on NC bending forming quality for high strength thin-wall tube

薄壁管数控弯曲成形中的柔性芯模是影响薄壁管成形质量的关键因素。利用有限元分析软件Dynaform建立了高强度薄壁管数控弯曲过程的有限元模型,并对其可靠性进行实验验证。研究了芯棒与管材间隙、球芯棒个数、球芯棒与管材间隙、芯棒与管材摩擦条件等芯模参数对高强度薄壁管数控弯曲过程中壁厚变化和截面畸变的影响规律。结果表明:随着芯棒与管材间隙的增大,壁厚减薄率减小,截面畸变率增大不明显,芯棒与管材间隙主要影响管材弯曲结束位置;随着球芯棒个数的增加,壁厚减薄率增大,截面畸变程度减小;随着球芯棒与管材间隙的增大,壁厚减薄率减小,截面畸变率增大;芯棒与管材内壁的摩擦越小,越有利于降低壁厚减薄率。

Flexible mandrel is a key factor that influences the forming quality of thin-walled tube in NC bending process. A finite element model of NC bending process for high strength thin-walled tube was established by FE software Dynaform,and its reliability was verified by experiment. It was studied that the influential regularities of the mandrel parameters,such as mandrel and tube clearance,ball mandrel number,ball mandrels and tube clearance,and mandrel and tube friction condition,on the thickness change and the cross section distortion in NC bending process. Results show that with the increase of the mandrel and tube clearance,the wall thinning rate decreases,and the cross section distortion has little increase,and the mandrel and tube clearance mainly affects the bending end position. With the increase of ball mandrels number,the wall thinning rate has a tendency to increase,but the cross section distortion is reduced. With the increase of the ball mandrels and tube clearance,the wall thinning rate decreases,while the cross section distortion increases. The smaller the friction between mandrel and tube internal is,the more the wall thinning rate decreases.